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+This is grub.info, produced by makeinfo version 6.3 from grub.texi.
+
+This manual is for GNU GRUB (version 2.06, 10 May 2021).
+
+ Copyright (C)
+1999,2000,2001,2002,2004,2006,2008,2009,2010,2011,2012,2013 Free
+Software Foundation, Inc.
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU Free Documentation License,
+ Version 1.2 or any later version published by the Free Software
+ Foundation; with no Invariant Sections.
+INFO-DIR-SECTION Kernel
+START-INFO-DIR-ENTRY
+* GRUB: (grub). The GRand Unified Bootloader
+* grub-install: (grub)Invoking grub-install. Install GRUB on your drive
+* grub-mkconfig: (grub)Invoking grub-mkconfig. Generate GRUB configuration
+* grub-mkpasswd-pbkdf2: (grub)Invoking grub-mkpasswd-pbkdf2.
+* grub-mkrelpath: (grub)Invoking grub-mkrelpath.
+* grub-mkrescue: (grub)Invoking grub-mkrescue. Make a GRUB rescue image
+* grub-mount: (grub)Invoking grub-mount. Mount a file system using GRUB
+* grub-probe: (grub)Invoking grub-probe. Probe device information
+* grub-script-check: (grub)Invoking grub-script-check.
+END-INFO-DIR-ENTRY
+
+
+Indirect:
+grub.info-1: 1152
+grub.info-2: 311540
+
+Tag Table:
+(Indirect)
+Node: Top1152
+Node: Introduction4200
+Node: Overview4644
+Node: Overview-Footnotes6634
+Ref: Overview-Footnote-16695
+Node: History6857
+Node: Changes from GRUB Legacy8947
+Node: Features11423
+Node: Features-Footnotes17850
+Ref: Features-Footnote-117911
+Ref: Features-Footnote-218007
+Ref: Features-Footnote-318154
+Node: Role of a boot loader18299
+Node: Role of a boot loader-Footnotes19638
+Ref: Role of a boot loader-Footnote-119725
+Node: Naming convention19804
+Node: OS-specific notes about grub tools22715
+Node: Installation23751
+Node: Installing GRUB using grub-install24873
+Node: Making a GRUB bootable CD-ROM27188
+Node: Making a GRUB bootable CD-ROM-Footnotes29047
+Ref: Making a GRUB bootable CD-ROM-Footnote-129150
+Node: Device map29225
+Node: BIOS installation31192
+Node: Booting35643
+Node: General boot methods36178
+Node: Loading an operating system directly36921
+Node: Chain-loading37652
+Node: Loopback booting38623
+Node: LVM cache booting40297
+Node: OS-specific notes41563
+Node: GNU/Hurd41853
+Node: GNU/Linux42976
+Node: NetBSD44294
+Node: DOS/Windows45768
+Node: Configuration47546
+Node: Simple configuration48258
+Node: Root Identifcation Heuristics64564
+Node: Shell-like scripting67578
+Node: Shell-like scripting-Footnotes75641
+Ref: Shell-like scripting-Footnote-175726
+Node: Multi-boot manual config75853
+Node: Embedded configuration79462
+Node: Theme file format82298
+Ref: Pixmap-styled progress bar83757
+Ref: Plain progress bar, drawn with solid color.83769
+Ref: An example of the slices (in red) used for a terminal window. This drawing was created and sliced in Inkscape_, as the next section explains.87261
+Node: Network107673
+Node: Serial terminal111987
+Node: Vendor power-on keys114224
+Node: Images116159
+Node: Core image size limitation121134
+Node: Filesystem123698
+Node: Device syntax124407
+Node: File name syntax127108
+Node: Block list syntax128154
+Node: Interface128888
+Node: Command-line interface129712
+Node: Command-line interface-Footnotes131656
+Ref: Command-line interface-Footnote-1131745
+Node: Menu interface131840
+Node: Menu entry editor132852
+Node: Environment133590
+Node: Special environment variables134293
+Node: biosnum135347
+Node: check_signatures135871
+Node: chosen136158
+Node: cmdpath136601
+Node: color_highlight137028
+Node: color_normal137440
+Node: config_directory139103
+Node: config_file139397
+Node: debug139790
+Node: default140229
+Node: fallback141657
+Node: gfxmode141990
+Node: gfxpayload142788
+Node: gfxterm_font143942
+Node: grub_cpu144242
+Node: grub_platform144530
+Node: icondir144822
+Node: lang145139
+Node: locale_dir145608
+Node: menu_color_highlight146117
+Node: menu_color_normal146613
+Node: net_<INTERFACE>_boot_file147114
+Node: net_<INTERFACE>_dhcp_server_name147357
+Node: net_<INTERFACE>_domain147619
+Node: net_<INTERFACE>_extensionspath147866
+Node: net_<INTERFACE>_hostname148121
+Node: net_<INTERFACE>_ip148360
+Node: net_<INTERFACE>_mac148576
+Node: net_<INTERFACE>_next_server148797
+Node: net_<INTERFACE>_rootpath149040
+Node: net_default_interface149279
+Node: net_default_ip149499
+Node: net_default_mac149696
+Node: net_default_server149892
+Node: pager150085
+Node: prefix150341
+Node: pxe_blksize150790
+Node: pxe_default_gateway150967
+Node: pxe_default_server151172
+Node: root151368
+Node: superusers151909
+Node: theme152157
+Node: timeout152478
+Node: timeout_style153115
+Node: Environment block153500
+Node: Commands154932
+Node: Menu-specific commands155802
+Node: menuentry156530
+Node: submenu158081
+Node: General commands158630
+Node: serial159126
+Node: terminal_input160177
+Node: terminal_output160843
+Node: terminfo161510
+Node: Command-line and menu entry commands162741
+Node: [168063
+Node: acpi168249
+Node: authenticate169562
+Node: background_color169989
+Node: background_image170662
+Node: badram171212
+Node: blocklist172597
+Node: boot172831
+Node: cat173153
+Node: chainloader173789
+Node: clear174417
+Node: cmosclean174603
+Node: cmosdump174907
+Node: cmostest175202
+Node: cmp175560
+Node: configfile176111
+Node: cpuid176536
+Node: crc177107
+Node: cryptomount177381
+Node: cutmem178375
+Node: date179254
+Node: devicetree179798
+Node: distrust180340
+Node: drivemap181121
+Node: echo181928
+Node: eval182871
+Node: export183154
+Node: false183465
+Node: gettext183761
+Node: gptsync184208
+Node: halt185153
+Node: hashsum185484
+Node: help186710
+Node: initrd187177
+Node: initrd16187612
+Node: insmod188146
+Node: keystatus188368
+Node: linux189007
+Node: linux16189910
+Node: list_env190624
+Node: list_trusted190990
+Node: load_env191573
+Node: loadfont193246
+Node: loopback193617
+Node: ls194065
+Node: lsfonts194607
+Node: lsmod194789
+Node: md5sum194979
+Node: module195258
+Node: multiboot195570
+Node: nativedisk196679
+Node: normal197078
+Node: normal_exit197845
+Node: parttool198167
+Node: password199673
+Node: password_pbkdf2199955
+Node: play200363
+Node: probe201111
+Node: rdmsr201613
+Node: read202396
+Node: reboot202740
+Node: regexp202923
+Node: rmmod203460
+Node: save_env203653
+Node: search204675
+Node: sendkey205453
+Node: set211879
+Node: sha1sum212181
+Node: sha256sum212466
+Node: sha512sum212765
+Node: sleep213062
+Node: smbios213586
+Node: source216629
+Node: test217182
+Node: true219951
+Node: trust220237
+Node: unset221029
+Node: verify_detached221243
+Node: videoinfo222288
+Node: wrmsr222566
+Node: xen_hypervisor223380
+Node: xen_module223841
+Node: Networking commands224365
+Node: net_add_addr225387
+Node: net_add_dns225907
+Node: net_add_route226183
+Node: net_bootp226713
+Node: net_del_addr227078
+Node: net_del_dns227318
+Node: net_del_route227565
+Node: net_dhcp227799
+Node: net_get_dhcp_option229778
+Node: net_ipv6_autoconf230259
+Node: net_ls_addr230680
+Node: net_ls_cards230928
+Node: net_ls_dns231164
+Node: net_ls_routes231395
+Node: net_nslookup231602
+Node: Internationalisation231886
+Node: Security238718
+Node: Authentication and authorisation239294
+Node: Using digital signatures242410
+Node: UEFI secure boot and shim245680
+Node: Secure Boot Advanced Targeting246827
+Node: Measured Boot247858
+Node: Lockdown249823
+Node: Platform limitations250316
+Node: Platform-specific operations258325
+Node: Supported kernels259390
+Node: Troubleshooting267027
+Node: GRUB only offers a rescue shell267297
+Node: Firmware stalls instead of booting GRUB270306
+Node: Invoking grub-install270937
+Node: Invoking grub-mkconfig273107
+Node: Invoking grub-mkpasswd-pbkdf2273744
+Node: Invoking grub-mkrelpath274403
+Node: Invoking grub-mkrescue275176
+Node: Invoking grub-mount276925
+Node: Invoking grub-probe279974
+Node: Invoking grub-script-check282568
+Node: Obtaining and Building GRUB283312
+Node: Reporting bugs284555
+Node: Future287371
+Node: Copying This Manual287771
+Node: GNU Free Documentation License287999
+Node: Index311540
+
+End Tag Table
diff --git a/docs/grub.info-1 b/docs/grub.info-1
new file mode 100644
index 0000000..8a857f5
--- /dev/null
+++ b/docs/grub.info-1
@@ -0,0 +1,7554 @@
+This is grub.info, produced by makeinfo version 6.3 from grub.texi.
+
+This manual is for GNU GRUB (version 2.06, 10 May 2021).
+
+ Copyright (C)
+1999,2000,2001,2002,2004,2006,2008,2009,2010,2011,2012,2013 Free
+Software Foundation, Inc.
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU Free Documentation License,
+ Version 1.2 or any later version published by the Free Software
+ Foundation; with no Invariant Sections.
+INFO-DIR-SECTION Kernel
+START-INFO-DIR-ENTRY
+* GRUB: (grub). The GRand Unified Bootloader
+* grub-install: (grub)Invoking grub-install. Install GRUB on your drive
+* grub-mkconfig: (grub)Invoking grub-mkconfig. Generate GRUB configuration
+* grub-mkpasswd-pbkdf2: (grub)Invoking grub-mkpasswd-pbkdf2.
+* grub-mkrelpath: (grub)Invoking grub-mkrelpath.
+* grub-mkrescue: (grub)Invoking grub-mkrescue. Make a GRUB rescue image
+* grub-mount: (grub)Invoking grub-mount. Mount a file system using GRUB
+* grub-probe: (grub)Invoking grub-probe. Probe device information
+* grub-script-check: (grub)Invoking grub-script-check.
+END-INFO-DIR-ENTRY
+
+
+File: grub.info, Node: Top, Next: Introduction, Up: (dir)
+
+GNU GRUB manual
+***************
+
+This is the documentation of GNU GRUB, the GRand Unified Bootloader, a
+flexible and powerful boot loader program for a wide range of
+architectures.
+
+ This edition documents version 2.06.
+
+ This manual is for GNU GRUB (version 2.06, 10 May 2021).
+
+ Copyright (C)
+1999,2000,2001,2002,2004,2006,2008,2009,2010,2011,2012,2013 Free
+Software Foundation, Inc.
+
+ Permission is granted to copy, distribute and/or modify this
+ document under the terms of the GNU Free Documentation License,
+ Version 1.2 or any later version published by the Free Software
+ Foundation; with no Invariant Sections.
+
+* Menu:
+
+* Introduction:: Capturing the spirit of GRUB
+* Naming convention:: Names of your drives in GRUB
+* OS-specific notes about grub tools::
+ Some notes about OS-specific behaviour of GRUB
+ tools
+* Installation:: Installing GRUB on your drive
+* Booting:: How to boot different operating systems
+* Configuration:: Writing your own configuration file
+* Theme file format:: Format of GRUB theme files
+* Network:: Downloading OS images from a network
+* Serial terminal:: Using GRUB via a serial line
+* Vendor power-on keys:: Changing GRUB behaviour on vendor power-on keys
+* Images:: GRUB image files
+* Core image size limitation:: GRUB image files size limitations
+* Filesystem:: Filesystem syntax and semantics
+* Interface:: The menu and the command-line
+* Environment:: GRUB environment variables
+* Commands:: The list of available builtin commands
+* Internationalisation:: Topics relating to language support
+* Security:: Authentication, authorisation, and signatures
+* Platform limitations:: The list of platform-specific limitations
+* Platform-specific operations:: Platform-specific operations
+* Supported kernels:: The list of supported kernels
+* Troubleshooting:: Error messages produced by GRUB
+* Invoking grub-install:: How to use the GRUB installer
+* Invoking grub-mkconfig:: Generate a GRUB configuration file
+* Invoking grub-mkpasswd-pbkdf2::
+ Generate GRUB password hashes
+* Invoking grub-mkrelpath:: Make system path relative to its root
+* Invoking grub-mkrescue:: Make a GRUB rescue image
+* Invoking grub-mount:: Mount a file system using GRUB
+* Invoking grub-probe:: Probe device information for GRUB
+* Invoking grub-script-check:: Check GRUB script file for syntax errors
+* Obtaining and Building GRUB:: How to obtain and build GRUB
+* Reporting bugs:: Where you should send a bug report
+* Future:: Some future plans on GRUB
+* Copying This Manual:: Copying This Manual
+* Index::
+
+
+File: grub.info, Node: Introduction, Next: Naming convention, Prev: Top, Up: Top
+
+1 Introduction to GRUB
+**********************
+
+* Menu:
+
+* Overview:: What exactly GRUB is and how to use it
+* History:: From maggot to house fly
+* Changes from GRUB Legacy:: Differences from previous versions
+* Features:: GRUB features
+* Role of a boot loader:: The role of a boot loader
+
+
+File: grub.info, Node: Overview, Next: History, Up: Introduction
+
+1.1 Overview
+============
+
+Briefly, a "boot loader" is the first software program that runs when a
+computer starts. It is responsible for loading and transferring control
+to an operating system "kernel" software (such as Linux or GNU Mach).
+The kernel, in turn, initializes the rest of the operating system (e.g.
+a GNU system).
+
+ GNU GRUB is a very powerful boot loader, which can load a wide
+variety of free operating systems, as well as proprietary operating
+systems with chain-loading(1) (*note Overview-Footnote-1::). GRUB is
+designed to address the complexity of booting a personal computer; both
+the program and this manual are tightly bound to that computer platform,
+although porting to other platforms may be addressed in the future.
+
+ One of the important features in GRUB is flexibility; GRUB
+understands filesystems and kernel executable formats, so you can load
+an arbitrary operating system the way you like, without recording the
+physical position of your kernel on the disk. Thus you can load the
+kernel just by specifying its file name and the drive and partition
+where the kernel resides.
+
+ When booting with GRUB, you can use either a command-line interface
+(*note Command-line interface::), or a menu interface (*note Menu
+interface::). Using the command-line interface, you type the drive
+specification and file name of the kernel manually. In the menu
+interface, you just select an OS using the arrow keys. The menu is
+based on a configuration file which you prepare beforehand (*note
+Configuration::). While in the menu, you can switch to the command-line
+mode, and vice-versa. You can even edit menu entries before using them.
+
+ In the following chapters, you will learn how to specify a drive, a
+partition, and a file name (*note Naming convention::) to GRUB, how to
+install GRUB on your drive (*note Installation::), and how to boot your
+OSes (*note Booting::), step by step.
+
+
+File: grub.info, Node: Overview-Footnotes, Up: Overview
+
+ (1) "chain-load" is the mechanism for loading unsupported operating
+systems by loading another boot loader. It is typically used for
+loading DOS or Windows.
+
+
+File: grub.info, Node: History, Next: Changes from GRUB Legacy, Prev: Overview, Up: Introduction
+
+1.2 History of GRUB
+===================
+
+GRUB originated in 1995 when Erich Boleyn was trying to boot the GNU
+Hurd with the University of Utah's Mach 4 microkernel (now known as GNU
+Mach). Erich and Brian Ford designed the Multiboot Specification (*note
+Multiboot Specification: (multiboot)Top.), because they were determined
+not to add to the large number of mutually-incompatible PC boot methods.
+
+ Erich then began modifying the FreeBSD boot loader so that it would
+understand Multiboot. He soon realized that it would be a lot easier to
+write his own boot loader from scratch than to keep working on the
+FreeBSD boot loader, and so GRUB was born.
+
+ Erich added many features to GRUB, but other priorities prevented him
+from keeping up with the demands of its quickly-expanding user base. In
+1999, Gordon Matzigkeit and Yoshinori K. Okuji adopted GRUB as an
+official GNU package, and opened its development by making the latest
+sources available via anonymous CVS. *Note Obtaining and Building
+GRUB::, for more information.
+
+ Over the next few years, GRUB was extended to meet many needs, but it
+quickly became clear that its design was not keeping up with the
+extensions being made to it, and we reached the point where it was very
+difficult to make any further changes without breaking existing
+features. Around 2002, Yoshinori K. Okuji started work on PUPA
+(Preliminary Universal Programming Architecture for GNU GRUB), aiming to
+rewrite the core of GRUB to make it cleaner, safer, more robust, and
+more powerful. PUPA was eventually renamed to GRUB 2, and the original
+version of GRUB was renamed to GRUB Legacy. Small amounts of
+maintenance continued to be done on GRUB Legacy, but the last release
+(0.97) was made in 2005 and at the time of writing it seems unlikely
+that there will be another.
+
+ By around 2007, GNU/Linux distributions started to use GRUB 2 to
+limited extents, and by the end of 2009 multiple major distributions
+were installing it by default.
+
+
+File: grub.info, Node: Changes from GRUB Legacy, Next: Features, Prev: History, Up: Introduction
+
+1.3 Differences from previous versions
+======================================
+
+GRUB 2 is a rewrite of GRUB (*note History::), although it shares many
+characteristics with the previous version, now known as GRUB Legacy.
+Users of GRUB Legacy may need some guidance to find their way around
+this new version.
+
+ * The configuration file has a new name ('grub.cfg' rather than
+ 'menu.lst' or 'grub.conf'), new syntax (*note Configuration::) and
+ many new commands (*note Commands::). Configuration cannot be
+ copied over directly, although most GRUB Legacy users should not
+ find the syntax too surprising.
+
+ * 'grub.cfg' is typically automatically generated by 'grub-mkconfig'
+ (*note Simple configuration::). This makes it easier to handle
+ versioned kernel upgrades.
+
+ * Partition numbers in GRUB device names now start at 1, not 0 (*note
+ Naming convention::).
+
+ * The configuration file is now written in something closer to a full
+ scripting language: variables, conditionals, and loops are
+ available.
+
+ * A small amount of persistent storage is available across reboots,
+ using the 'save_env' and 'load_env' commands in GRUB and the
+ 'grub-editenv' utility. This is not available in all
+ configurations (*note Environment block::).
+
+ * GRUB 2 has more reliable ways to find its own files and those of
+ target kernels on multiple-disk systems, and has commands (*note
+ search::) to find devices using file system labels or Universally
+ Unique Identifiers (UUIDs).
+
+ * GRUB 2 is available for several other types of system in addition
+ to the PC BIOS systems supported by GRUB Legacy: PC EFI, PC
+ coreboot, PowerPC, SPARC, and MIPS Lemote Yeeloong are all
+ supported.
+
+ * Many more file systems are supported, including but not limited to
+ ext4, HFS+, and NTFS.
+
+ * GRUB 2 can read files directly from LVM and RAID devices.
+
+ * A graphical terminal and a graphical menu system are available.
+
+ * GRUB 2's interface can be translated, including menu entry names.
+
+ * The image files (*note Images::) that make up GRUB have been
+ reorganised; Stage 1, Stage 1.5, and Stage 2 are no more.
+
+ * GRUB 2 puts many facilities in dynamically loaded modules, allowing
+ the core image to be smaller, and allowing the core image to be
+ built in more flexible ways.
+
+
+File: grub.info, Node: Features, Next: Role of a boot loader, Prev: Changes from GRUB Legacy, Up: Introduction
+
+1.4 GRUB features
+=================
+
+The primary requirement for GRUB is that it be compliant with the
+"Multiboot Specification", which is described in *note Multiboot
+Specification: (multiboot)Top.
+
+ The other goals, listed in approximate order of importance, are:
+
+ * Basic functions must be straightforward for end-users.
+
+ * Rich functionality to support kernel experts and designers.
+
+ * Backward compatibility for booting FreeBSD, NetBSD, OpenBSD, and
+ Linux. Proprietary kernels (such as DOS, Windows NT, and OS/2) are
+ supported via a chain-loading function.
+
+ Except for specific compatibility modes (chain-loading and the Linux
+"piggyback" format), all kernels will be started in much the same state
+as in the Multiboot Specification. Only kernels loaded at 1 megabyte or
+above are presently supported. Any attempt to load below that boundary
+will simply result in immediate failure and an error message reporting
+the problem.
+
+ In addition to the requirements above, GRUB has the following
+features (note that the Multiboot Specification doesn't require all the
+features that GRUB supports):
+
+Recognize multiple executable formats
+ Support many of the "a.out" variants plus "ELF". Symbol tables are
+ also loaded.
+
+Support non-Multiboot kernels
+ Support many of the various free 32-bit kernels that lack Multiboot
+ compliance (primarily FreeBSD, NetBSD(1) (*note
+ Features-Footnote-1::), OpenBSD, and Linux). Chain-loading of
+ other boot loaders is also supported.
+
+Load multiples modules
+ Fully support the Multiboot feature of loading multiple modules.
+
+Load a configuration file
+ Support a human-readable text configuration file with preset boot
+ commands. You can also load another configuration file dynamically
+ and embed a preset configuration file in a GRUB image file. The
+ list of commands (*note Commands::) are a superset of those
+ supported on the command-line. An example configuration file is
+ provided in *note Configuration::.
+
+Provide a menu interface
+ A menu interface listing preset boot commands, with a programmable
+ timeout, is available. There is no fixed limit on the number of
+ boot entries, and the current implementation has space for several
+ hundred.
+
+Have a flexible command-line interface
+ A fairly flexible command-line interface, accessible from the menu,
+ is available to edit any preset commands, or write a new boot
+ command set from scratch. If no configuration file is present,
+ GRUB drops to the command-line.
+
+ The list of commands (*note Commands::) are a subset of those
+ supported for configuration files. Editing commands closely
+ resembles the Bash command-line (*note Bash: (features)Command Line
+ Editing.), with <TAB>-completion of commands, devices, partitions,
+ and files in a directory depending on context.
+
+Support multiple filesystem types
+ Support multiple filesystem types transparently, plus a useful
+ explicit blocklist notation. The currently supported filesystem
+ types are "Amiga Fast FileSystem (AFFS)", "AtheOS fs", "BeFS",
+ "BtrFS" (including raid0, raid1, raid10, gzip and lzo), "cpio"
+ (little- and big-endian bin, odc and newc variants), "Linux
+ ext2/ext3/ext4", "DOS FAT12/FAT16/FAT32", "exFAT", "F2FS", "HFS",
+ "HFS+", "ISO9660" (including Joliet, Rock-ridge and multi-chunk
+ files), "JFS", "Minix fs" (versions 1, 2 and 3), "nilfs2", "NTFS"
+ (including compression), "ReiserFS", "ROMFS", "Amiga Smart
+ FileSystem (SFS)", "Squash4", "tar", "UDF", "BSD UFS/UFS2", "XFS",
+ and "ZFS" (including lzjb, gzip, zle, mirror, stripe, raidz1/2/3
+ and encryption in AES-CCM and AES-GCM). *Note Filesystem::, for
+ more information.
+
+Support automatic decompression
+ Can decompress files which were compressed by 'gzip' or 'xz'(2)
+ (*note Features-Footnote-2::). This function is both automatic and
+ transparent to the user (i.e. all functions operate upon the
+ uncompressed contents of the specified files). This greatly
+ reduces a file size and loading time, a particularly great benefit
+ for floppies.(3) (*note Features-Footnote-3::)
+
+ It is conceivable that some kernel modules should be loaded in a
+ compressed state, so a different module-loading command can be
+ specified to avoid uncompressing the modules.
+
+Access data on any installed device
+ Support reading data from any or all floppies or hard disk(s)
+ recognized by the BIOS, independent of the setting of the root
+ device.
+
+Be independent of drive geometry translations
+ Unlike many other boot loaders, GRUB makes the particular drive
+ translation irrelevant. A drive installed and running with one
+ translation may be converted to another translation without any
+ adverse effects or changes in GRUB's configuration.
+
+Detect all installed RAM
+ GRUB can generally find all the installed RAM on a PC-compatible
+ machine. It uses an advanced BIOS query technique for finding all
+ memory regions. As described on the Multiboot Specification (*note
+ Multiboot Specification: (multiboot)Top.), not all kernels make use
+ of this information, but GRUB provides it for those who do.
+
+Support Logical Block Address mode
+ In traditional disk calls (called "CHS mode"), there is a geometry
+ translation problem, that is, the BIOS cannot access over 1024
+ cylinders, so the accessible space is limited to at least 508 MB
+ and to at most 8GB. GRUB can't universally solve this problem, as
+ there is no standard interface used in all machines. However,
+ several newer machines have the new interface, Logical Block
+ Address ("LBA") mode. GRUB automatically detects if LBA mode is
+ available and uses it if available. In LBA mode, GRUB can access
+ the entire disk.
+
+Support network booting
+ GRUB is basically a disk-based boot loader but also has network
+ support. You can load OS images from a network by using the "TFTP"
+ protocol.
+
+Support remote terminals
+ To support computers with no console, GRUB provides remote terminal
+ support, so that you can control GRUB from a remote host. Only
+ serial terminal support is implemented at the moment.
+
+
+File: grub.info, Node: Features-Footnotes, Up: Features
+
+ (1) The NetBSD/i386 kernel is Multiboot-compliant, but lacks support
+for Multiboot modules.
+
+ (2) Only CRC32 data integrity check is supported (xz default is CRC64
+so one should use -check=crc32 option). LZMA BCJ filters are supported.
+
+ (3) There are a few pathological cases where loading a very badly
+organized ELF kernel might take longer, but in practice this never
+happen.
+
+
+File: grub.info, Node: Role of a boot loader, Prev: Features, Up: Introduction
+
+1.5 The role of a boot loader
+=============================
+
+The following is a quotation from Gordon Matzigkeit, a GRUB fanatic:
+
+ Some people like to acknowledge both the operating system and
+ kernel when they talk about their computers, so they might say they
+ use "GNU/Linux" or "GNU/Hurd". Other people seem to think that the
+ kernel is the most important part of the system, so they like to
+ call their GNU operating systems "Linux systems."
+
+ I, personally, believe that this is a grave injustice, because the
+ _boot loader_ is the most important software of all. I used to
+ refer to the above systems as either "LILO"(1) (*note Role of a
+ boot loader-Footnote-1::) or "GRUB" systems.
+
+ Unfortunately, nobody ever understood what I was talking about; now
+ I just use the word "GNU" as a pseudonym for GRUB.
+
+ So, if you ever hear people talking about their alleged "GNU"
+ systems, remember that they are actually paying homage to the best
+ boot loader around... GRUB!
+
+ We, the GRUB maintainers, do not (usually) encourage Gordon's level
+of fanaticism, but it helps to remember that boot loaders deserve
+recognition. We hope that you enjoy using GNU GRUB as much as we did
+writing it.
+
+
+File: grub.info, Node: Role of a boot loader-Footnotes, Up: Role of a boot loader
+
+ (1) The LInux LOader, a boot loader that everybody uses, but nobody
+likes.
+
+
+File: grub.info, Node: Naming convention, Next: OS-specific notes about grub tools, Prev: Introduction, Up: Top
+
+2 Naming convention
+*******************
+
+The device syntax used in GRUB is a wee bit different from what you may
+have seen before in your operating system(s), and you need to know it so
+that you can specify a drive/partition.
+
+ Look at the following examples and explanations:
+
+ (fd0)
+
+ First of all, GRUB requires that the device name be enclosed with '('
+and ')'. The 'fd' part means that it is a floppy disk. The number '0'
+is the drive number, which is counted from _zero_. This expression
+means that GRUB will use the whole floppy disk.
+
+ (hd0,msdos2)
+
+ Here, 'hd' means it is a hard disk drive. The first integer '0'
+indicates the drive number, that is, the first hard disk, the string
+'msdos' indicates the partition scheme, while the second integer, '2',
+indicates the partition number (or the PC slice number in the BSD
+terminology). The partition numbers are counted from _one_, not from
+zero (as was the case in previous versions of GRUB). This expression
+means the second partition of the first hard disk drive. In this case,
+GRUB uses one partition of the disk, instead of the whole disk.
+
+ (hd0,msdos5)
+
+ This specifies the first "extended partition" of the first hard disk
+drive. Note that the partition numbers for extended partitions are
+counted from '5', regardless of the actual number of primary partitions
+on your hard disk.
+
+ (hd1,msdos1,bsd1)
+
+ This means the BSD 'a' partition on first PC slice number of the
+second hard disk.
+
+ Of course, to actually access the disks or partitions with GRUB, you
+need to use the device specification in a command, like 'set root=(fd0)'
+or 'parttool (hd0,msdos3) hidden-'. To help you find out which number
+specifies a partition you want, the GRUB command-line (*note
+Command-line interface::) options have argument completion. This means
+that, for example, you only need to type
+
+ set root=(
+
+ followed by a <TAB>, and GRUB will display the list of drives,
+partitions, or file names. So it should be quite easy to determine the
+name of your target partition, even with minimal knowledge of the
+syntax.
+
+ Note that GRUB does _not_ distinguish IDE from SCSI - it simply
+counts the drive numbers from zero, regardless of their type. Normally,
+any IDE drive number is less than any SCSI drive number, although that
+is not true if you change the boot sequence by swapping IDE and SCSI
+drives in your BIOS.
+
+ Now the question is, how to specify a file? Again, consider an
+example:
+
+ (hd0,msdos1)/vmlinuz
+
+ This specifies the file named 'vmlinuz', found on the first partition
+of the first hard disk drive. Note that the argument completion works
+with file names, too.
+
+ That was easy, admit it. Now read the next chapter, to find out how
+to actually install GRUB on your drive.
+
+
+File: grub.info, Node: OS-specific notes about grub tools, Next: Installation, Prev: Naming convention, Up: Top
+
+3 OS-specific notes about grub tools
+************************************
+
+On OS which have device nodes similar to Unix-like OS GRUB tools use the
+OS name. E.g. for GNU/Linux:
+
+ # grub-install /dev/sda
+
+ On AROS we use another syntax. For volumes:
+
+ //:<volume name>
+
+ E.g.
+
+ //:DH0
+
+ For disks we use syntax:
+ //:<driver name>/unit/flags
+
+ E.g.
+
+ # grub-install //:ata.device/0/0
+
+ On Windows we use UNC path. For volumes it's typically
+
+ \\?\Volume{<GUID>}
+ \\?\<drive letter>:
+
+ E.g.
+
+ \\?\Volume{17f34d50-cf64-4b02-800e-51d79c3aa2ff}
+ \\?\C:
+
+ For disks it's
+
+ \\?\PhysicalDrive<number>
+
+ E.g.
+
+ # grub-install \\?\PhysicalDrive0
+
+ Beware that you may need to further escape the backslashes depending
+on your shell.
+
+ When compiled with cygwin support then cygwin drive names are
+automatically when needed. E.g.
+
+ # grub-install /dev/sda
+
+
+File: grub.info, Node: Installation, Next: Booting, Prev: OS-specific notes about grub tools, Up: Top
+
+4 Installation
+**************
+
+In order to install GRUB as your boot loader, you need to first install
+the GRUB system and utilities under your UNIX-like operating system
+(*note Obtaining and Building GRUB::). You can do this either from the
+source tarball, or as a package for your OS.
+
+ After you have done that, you need to install the boot loader on a
+drive (floppy or hard disk) by using the utility 'grub-install' (*note
+Invoking grub-install::) on a UNIX-like OS.
+
+ GRUB comes with boot images, which are normally put in the directory
+'/usr/lib/grub/<cpu>-<platform>' (for BIOS-based machines
+'/usr/lib/grub/i386-pc'). Hereafter, the directory where GRUB images
+are initially placed (normally '/usr/lib/grub/<cpu>-<platform>') will be
+called the "image directory", and the directory where the boot loader
+needs to find them (usually '/boot') will be called the "boot
+directory".
+
+* Menu:
+
+* Installing GRUB using grub-install::
+* Making a GRUB bootable CD-ROM::
+* Device map::
+* BIOS installation::
+
+
+File: grub.info, Node: Installing GRUB using grub-install, Next: Making a GRUB bootable CD-ROM, Up: Installation
+
+4.1 Installing GRUB using grub-install
+======================================
+
+For information on where GRUB should be installed on PC BIOS platforms,
+*note BIOS installation::.
+
+ In order to install GRUB under a UNIX-like OS (such as GNU), invoke
+the program 'grub-install' (*note Invoking grub-install::) as the
+superuser ("root").
+
+ The usage is basically very simple. You only need to specify one
+argument to the program, namely, where to install the boot loader. The
+argument has to be either a device file (like '/dev/hda'). For example,
+under Linux the following will install GRUB into the MBR of the first
+IDE disk:
+
+ # grub-install /dev/sda
+
+ Likewise, under GNU/Hurd, this has the same effect:
+
+ # grub-install /dev/hd0
+
+ But all the above examples assume that GRUB should put images under
+the '/boot' directory. If you want GRUB to put images under a directory
+other than '/boot', you need to specify the option '--boot-directory'.
+The typical usage is that you create a GRUB boot floppy with a
+filesystem. Here is an example:
+
+ # mke2fs /dev/fd0
+ # mount -t ext2 /dev/fd0 /mnt
+ # mkdir /mnt/boot
+ # grub-install --boot-directory=/mnt/boot /dev/fd0
+ # umount /mnt
+
+ Some BIOSes have a bug of exposing the first partition of a USB drive
+as a floppy instead of exposing the USB drive as a hard disk (they call
+it "USB-FDD" boot). In such cases, you need to install like this:
+
+ # losetup /dev/loop0 /dev/sdb1
+ # mount /dev/loop0 /mnt/usb
+ # grub-install --boot-directory=/mnt/usb/bugbios --force --allow-floppy /dev/loop0
+
+ This install doesn't conflict with standard install as long as they
+are in separate directories.
+
+ On EFI systems for fixed disk install you have to mount EFI System
+Partition. If you mount it at '/boot/efi' then you don't need any
+special arguments:
+
+ # grub-install
+
+ Otherwise you need to specify where your EFI System partition is
+mounted:
+
+ # grub-install --efi-directory=/mnt/efi
+
+ For removable installs you have to use '--removable' and specify both
+'--boot-directory' and '--efi-directory':
+
+ # grub-install --efi-directory=/mnt/usb --boot-directory=/mnt/usb/boot --removable
+
+
+File: grub.info, Node: Making a GRUB bootable CD-ROM, Next: Device map, Prev: Installing GRUB using grub-install, Up: Installation
+
+4.2 Making a GRUB bootable CD-ROM
+=================================
+
+GRUB supports the "no emulation mode" in the El Torito specification(1)
+(*note Making a GRUB bootable CD-ROM-Footnote-1::). This means that you
+can use the whole CD-ROM from GRUB and you don't have to make a floppy
+or hard disk image file, which can cause compatibility problems.
+
+ For booting from a CD-ROM, GRUB uses a special image called
+'cdboot.img', which is concatenated with 'core.img'. The 'core.img'
+used for this should be built with at least the 'iso9660' and 'biosdisk'
+modules. Your bootable CD-ROM will usually also need to include a
+configuration file 'grub.cfg' and some other GRUB modules.
+
+ To make a simple generic GRUB rescue CD, you can use the
+'grub-mkrescue' program (*note Invoking grub-mkrescue::):
+
+ $ grub-mkrescue -o grub.iso
+
+ You will often need to include other files in your image. To do
+this, first make a top directory for the bootable image, say, 'iso':
+
+ $ mkdir iso
+
+ Make a directory for GRUB:
+
+ $ mkdir -p iso/boot/grub
+
+ If desired, make the config file 'grub.cfg' under 'iso/boot/grub'
+(*note Configuration::), and copy any files and directories for the disc
+to the directory 'iso/'.
+
+ Finally, make the image:
+
+ $ grub-mkrescue -o grub.iso iso
+
+ This produces a file named 'grub.iso', which then can be burned into
+a CD (or a DVD), or written to a USB mass storage device.
+
+ The root device will be set up appropriately on entering your
+'grub.cfg' configuration file, so you can refer to file names on the CD
+without needing to use an explicit device name. This makes it easier to
+produce rescue images that will work on both optical drives and USB mass
+storage devices.
+
+
+File: grub.info, Node: Making a GRUB bootable CD-ROM-Footnotes, Up: Making a GRUB bootable CD-ROM
+
+ (1) El Torito is a specification for bootable CD using BIOS
+functions.
+
+
+File: grub.info, Node: Device map, Next: BIOS installation, Prev: Making a GRUB bootable CD-ROM, Up: Installation
+
+4.3 The map between BIOS drives and OS devices
+==============================================
+
+If the device map file exists, the GRUB utilities ('grub-probe', etc.)
+read it to map BIOS drives to OS devices. This file consists of lines
+like this:
+
+ (DEVICE) FILE
+
+ DEVICE is a drive specified in the GRUB syntax (*note Device
+syntax::), and FILE is an OS file, which is normally a device file.
+
+ Historically, the device map file was used because GRUB device names
+had to be used in the configuration file, and they were derived from
+BIOS drive numbers. The map between BIOS drives and OS devices cannot
+always be guessed correctly: for example, GRUB will get the order wrong
+if you exchange the boot sequence between IDE and SCSI in your BIOS.
+
+ Unfortunately, even OS device names are not always stable. Modern
+versions of the Linux kernel may probe drives in a different order from
+boot to boot, and the prefix ('/dev/hd*' versus '/dev/sd*') may change
+depending on the driver subsystem in use. As a result, the device map
+file required frequent editing on some systems.
+
+ GRUB avoids this problem nowadays by using UUIDs or file system
+labels when generating 'grub.cfg', and we advise that you do the same
+for any custom menu entries you write. If the device map file does not
+exist, then the GRUB utilities will assume a temporary device map on the
+fly. This is often good enough, particularly in the common case of
+single-disk systems.
+
+ However, the device map file is not entirely obsolete yet, and it is
+used for overriding when current environment is different from the one
+on boot. Most common case is if you use a partition or logical volume
+as a disk for virtual machine. You can put any comments in the file if
+needed, as the GRUB utilities assume that a line is just a comment if
+the first character is '#'.
+
+
+File: grub.info, Node: BIOS installation, Prev: Device map, Up: Installation
+
+4.4 BIOS installation
+=====================
+
+MBR
+===
+
+The partition table format traditionally used on PC BIOS platforms is
+called the Master Boot Record (MBR) format; this is the format that
+allows up to four primary partitions and additional logical partitions.
+With this partition table format, there are two ways to install GRUB: it
+can be embedded in the area between the MBR and the first partition
+(called by various names, such as the "boot track", "MBR gap", or
+"embedding area", and which is usually at least 1000 KiB), or the core
+image can be installed in a file system and a list of the blocks that
+make it up can be stored in the first sector of that partition.
+
+ Modern tools usually leave MBR gap of at least 1023 KiB. This amount
+is sufficient to cover most configurations. Hence this value is
+recommended by the GRUB team.
+
+ Historically many tools left only 31 KiB of space. This is not
+enough to parse reliably difficult structures like Btrfs, ZFS, RAID or
+LVM, or to use difficult disk access methods like ahci. Hence GRUB will
+warn if attempted to install into small MBR gap except in a small number
+of configurations that were grandfathered. The grandfathered config
+must:
+
+ * use biosdisk as disk access module for '/boot' * not use any
+additional partition maps to access '/boot' * '/boot' must be on one of
+following filesystems: * AFFS, AFS, BFS, cpio, newc, odc, ext2/3/4, FAT,
+exFAT, F2FS, HFS, uncompressed HFS+, ISO9660, JFS, Minix, Minix2,
+Minix3, NILFS2, NTFS, ReiserFS, ROMFS, SFS, tar, UDF, UFS1, UFS2, XFS
+
+ MBR gap has few technical problems. There is no way to reserve space
+in the embedding area with complete safety, and some proprietary
+software is known to use it to make it difficult for users to work
+around licensing restrictions. GRUB works it around by detecting
+sectors by other software and avoiding them and protecting its own
+sectors using Reed-Solomon encoding.
+
+ GRUB team recommends having MBR gap of at least 1000 KiB
+
+ Should it be not possible GRUB has support for a fallback solution
+which is heavily recommended against. Installing to a filesystem means
+that GRUB is vulnerable to its blocks being moved around by filesystem
+features such as tail packing, or even by aggressive fsck
+implementations, so this approach is quite fragile; and this approach
+can only be used if the '/boot' filesystem is on the same disk that the
+BIOS boots from, so that GRUB does not have to rely on guessing BIOS
+drive numbers.
+
+ The GRUB development team generally recommends embedding GRUB before
+the first partition, unless you have special requirements. You must
+ensure that the first partition starts at least 1000 KiB (2000 sectors)
+from the start of the disk; on modern disks, it is often a performance
+advantage to align partitions on larger boundaries anyway, so the first
+partition might start 1 MiB from the start of the disk.
+
+GPT
+===
+
+Some newer systems use the GUID Partition Table (GPT) format. This was
+specified as part of the Extensible Firmware Interface (EFI), but it can
+also be used on BIOS platforms if system software supports it; for
+example, GRUB and GNU/Linux can be used in this configuration. With
+this format, it is possible to reserve a whole partition for GRUB,
+called the BIOS Boot Partition. GRUB can then be embedded into that
+partition without the risk of being overwritten by other software and
+without being contained in a filesystem which might move its blocks
+around.
+
+ When creating a BIOS Boot Partition on a GPT system, you should make
+sure that it is at least 31 KiB in size. (GPT-formatted disks are not
+usually particularly small, so we recommend that you make it larger than
+the bare minimum, such as 1 MiB, to allow plenty of room for growth.)
+You must also make sure that it has the proper partition type. Using
+GNU Parted, you can set this using a command such as the following:
+
+ # parted /dev/DISK set PARTITION-NUMBER bios_grub on
+
+ If you are using gdisk, set the partition type to '0xEF02'. With
+partitioning programs that require setting the GUID directly, it should
+be '21686148-6449-6e6f-744e656564454649'.
+
+ *Caution:* Be very careful which partition you select! When GRUB
+finds a BIOS Boot Partition during installation, it will automatically
+overwrite part of it. Make sure that the partition does not contain any
+other data.
+
+
+File: grub.info, Node: Booting, Next: Configuration, Prev: Installation, Up: Top
+
+5 Booting
+*********
+
+GRUB can load Multiboot-compliant kernels in a consistent way, but for
+some free operating systems you need to use some OS-specific magic.
+
+* Menu:
+
+* General boot methods:: How to boot OSes with GRUB generally
+* Loopback booting:: Notes on booting from loopbacks
+* LVM cache booting:: Notes on booting from LVM cache logical volume
+* OS-specific notes:: Notes on some operating systems
+
+
+File: grub.info, Node: General boot methods, Next: Loopback booting, Up: Booting
+
+5.1 How to boot operating systems
+=================================
+
+GRUB has two distinct boot methods. One of the two is to load an
+operating system directly, and the other is to chain-load another boot
+loader which then will load an operating system actually. Generally
+speaking, the former is more desirable, because you don't need to
+install or maintain other boot loaders and GRUB is flexible enough to
+load an operating system from an arbitrary disk/partition. However, the
+latter is sometimes required, since GRUB doesn't support all the
+existing operating systems natively.
+
+* Menu:
+
+* Loading an operating system directly::
+* Chain-loading::
+
+
+File: grub.info, Node: Loading an operating system directly, Next: Chain-loading, Up: General boot methods
+
+5.1.1 How to boot an OS directly with GRUB
+------------------------------------------
+
+Multiboot (*note Multiboot Specification: (multiboot)Top.) is the native
+format supported by GRUB. For the sake of convenience, there is also
+support for Linux, FreeBSD, NetBSD and OpenBSD. If you want to boot
+other operating systems, you will have to chain-load them (*note
+Chain-loading::).
+
+ FIXME: this section is incomplete.
+
+ 1. Run the command 'boot' (*note boot::).
+
+ However, DOS and Windows have some deficiencies, so you might have to
+use more complicated instructions. *Note DOS/Windows::, for more
+information.
+
+
+File: grub.info, Node: Chain-loading, Prev: Loading an operating system directly, Up: General boot methods
+
+5.1.2 Chain-loading an OS
+-------------------------
+
+Operating systems that do not support Multiboot and do not have specific
+support in GRUB (specific support is available for Linux, FreeBSD,
+NetBSD and OpenBSD) must be chain-loaded, which involves loading another
+boot loader and jumping to it in real mode.
+
+ The 'chainloader' command (*note chainloader::) is used to set this
+up. It is normally also necessary to load some GRUB modules and set the
+appropriate root device. Putting this together, we get something like
+this, for a Windows system on the first partition of the first hard
+disk:
+
+menuentry "Windows" {
+ insmod chain
+ insmod ntfs
+ set root=(hd0,1)
+ chainloader +1
+}
+
+ On systems with multiple hard disks, an additional workaround may be
+required. *Note DOS/Windows::.
+
+ Chain-loading is only supported on PC BIOS and EFI platforms.
+
+
+File: grub.info, Node: Loopback booting, Next: LVM cache booting, Prev: General boot methods, Up: Booting
+
+5.2 Loopback booting
+====================
+
+GRUB is able to read from an image (be it one of CD or HDD) stored on
+any of its accessible storages (refer to *note loopback:: command).
+However the OS itself should be able to find its root. This usually
+involves running a userspace program running before the real root is
+discovered. This is achieved by GRUB loading a specially made small
+image and passing it as ramdisk to the kernel. This is achieved by
+commands 'kfreebsd_module', 'knetbsd_module_elf', 'kopenbsd_ramdisk',
+'initrd' (*note initrd::), 'initrd16' (*note initrd::),
+'multiboot_module', 'multiboot2_module' or 'xnu_ramdisk' depending on
+the loader. Note that for knetbsd the image must be put inside
+miniroot.kmod and the whole miniroot.kmod has to be loaded. In kopenbsd
+payload this is disabled by default. Aditionally behaviour of initial
+ramdisk depends on command line options. Several distributors provide
+the image for this purpose or it's integrated in their standard ramdisk
+and activated by special option. Consult your kernel and distribution
+manual for more details. Other loaders like appleloader, chainloader
+(BIOS, EFI, coreboot), freedos, ntldr and plan9 provide no possibility
+of loading initial ramdisk and as far as author is aware the payloads in
+question don't support either initial ramdisk or discovering loopback
+boot in other way and as such not bootable this way. Please consider
+alternative boot methods like copying all files from the image to actual
+partition. Consult your OS documentation for more details
+
+
+File: grub.info, Node: LVM cache booting, Next: OS-specific notes, Prev: Loopback booting, Up: Booting
+
+5.3 Booting from LVM cache logical volume
+=========================================
+
+The LVM cache logical volume is the logical volume consisting of the
+original and the cache pool logical volume. The original is usually on
+a larger and slower storage device while the cache pool is on a smaller
+and faster one. The performance of the original volume can be improved
+by storing the frequently used data on the cache pool to utilize the
+greater performance of faster device.
+
+ GRUB boots from LVM cache logical volume merely by reading it's
+original logical volume so that dirty data in cache pool volume is
+disregarded. This is not a problem for "writethrough" cache mode as it
+ensures that any data written will be stored both on the cache and the
+origin LV. For the other cache mode "writeback", which delays writing
+from the cache pool back to the origin LV to boost performance, GRUB may
+fail to boot in the wake of accidental power outage due to it's
+inability to assemble the cache device for reading the required dirty
+data left behind. The situation will be improved after adding full
+support to the LVM cache logical volume in the future.
+
+
+File: grub.info, Node: OS-specific notes, Prev: LVM cache booting, Up: Booting
+
+5.4 Some caveats on OS-specific issues
+======================================
+
+Here, we describe some caveats on several operating systems.
+
+* Menu:
+
+* GNU/Hurd::
+* GNU/Linux::
+* NetBSD::
+* DOS/Windows::
+
+
+File: grub.info, Node: GNU/Hurd, Next: GNU/Linux, Up: OS-specific notes
+
+5.4.1 GNU/Hurd
+--------------
+
+Since GNU/Hurd is Multiboot-compliant, it is easy to boot it; there is
+nothing special about it. But do not forget that you have to specify a
+root partition to the kernel.
+
+ 1. Set GRUB's root device to the same drive as GNU/Hurd's. The
+ command 'search --set=root --file /boot/gnumach.gz' or similar may
+ help you (*note search::).
+
+ 2. Load the kernel and the modules, like this:
+
+ grub> multiboot /boot/gnumach.gz root=device:hd0s1
+ grub> module /hurd/ext2fs.static ext2fs --readonly \
+ --multiboot-command-line='${kernel-command-line}' \
+ --host-priv-port='${host-port}' \
+ --device-master-port='${device-port}' \
+ --exec-server-task='${exec-task}' -T typed '${root}' \
+ '$(task-create)' '$(task-resume)'
+ grub> module /lib/ld.so.1 exec /hurd/exec '$(exec-task=task-create)'
+
+ 3. Finally, run the command 'boot' (*note boot::).
+
+
+File: grub.info, Node: GNU/Linux, Next: NetBSD, Prev: GNU/Hurd, Up: OS-specific notes
+
+5.4.2 GNU/Linux
+---------------
+
+It is relatively easy to boot GNU/Linux from GRUB, because it somewhat
+resembles to boot a Multiboot-compliant OS.
+
+ 1. Set GRUB's root device to the same drive as GNU/Linux's. The
+ command 'search --set=root --file /vmlinuz' or similar may help you
+ (*note search::).
+
+ 2. Load the kernel using the command 'linux' (*note linux::):
+
+ grub> linux /vmlinuz root=/dev/sda1
+
+ If you need to specify some kernel parameters, just append them to
+ the command. For example, to set 'acpi' to 'off', do this:
+
+ grub> linux /vmlinuz root=/dev/sda1 acpi=off
+
+ See the documentation in the Linux source tree for complete
+ information on the available options.
+
+ With 'linux' GRUB uses 32-bit protocol. Some BIOS services like
+ APM or EDD aren't available with this protocol. In this case you
+ need to use 'linux16'
+
+ grub> linux16 /vmlinuz root=/dev/sda1 acpi=off
+
+ 3. If you use an initrd, execute the command 'initrd' (*note initrd::)
+ after 'linux':
+
+ grub> initrd /initrd
+
+ If you used 'linux16' you need to use 'initrd16':
+
+ grub> initrd16 /initrd
+
+ 4. Finally, run the command 'boot' (*note boot::).
+
+
+File: grub.info, Node: NetBSD, Next: DOS/Windows, Prev: GNU/Linux, Up: OS-specific notes
+
+5.4.3 NetBSD
+------------
+
+Booting a NetBSD kernel from GRUB is also relatively easy: first set
+GRUB's root device, then load the kernel and the modules, and finally
+run 'boot'.
+
+ 1. Set GRUB's root device to the partition holding the NetBSD root
+ file system. For a disk with a NetBSD disk label, this is usually
+ the first partition (a:). In that case, and assuming that the
+ partition is on the first hard disk, set GRUB's root device as
+ follows:
+
+ grub> insmod part_bsd
+ grub> set root=(hd0,netbsd1)
+
+ For a disk with a GUID Partition Table (GPT), and assuming that the
+ NetBSD root partition is the third GPT partition, do this:
+
+ grub> insmod part_gpt
+ grub> set root=(hd0,gpt3)
+
+ 2. Load the kernel using the command 'knetbsd':
+
+ grub> knetbsd /netbsd
+
+ Various options may be given to 'knetbsd'. These options are, for
+ the most part, the same as in the NetBSD boot loader. For
+ instance, to boot the system in single-user mode and with verbose
+ messages, do this:
+
+ grub> knetbsd /netbsd -s -v
+
+ 3. If needed, load kernel modules with the command
+ 'knetbsd_module_elf'. A typical example is the module for the root
+ file system:
+
+ grub> knetbsd_module_elf /stand/amd64/6.0/modules/ffs/ffs.kmod
+
+ 4. Finally, run the command 'boot' (*note boot::).
+
+
+File: grub.info, Node: DOS/Windows, Prev: NetBSD, Up: OS-specific notes
+
+5.4.4 DOS/Windows
+-----------------
+
+GRUB cannot boot DOS or Windows directly, so you must chain-load them
+(*note Chain-loading::). However, their boot loaders have some critical
+deficiencies, so it may not work to just chain-load them. To overcome
+the problems, GRUB provides you with two helper functions.
+
+ If you have installed DOS (or Windows) on a non-first hard disk, you
+have to use the disk swapping technique, because that OS cannot boot
+from any disks but the first one. The workaround used in GRUB is the
+command 'drivemap' (*note drivemap::), like this:
+
+ drivemap -s (hd0) (hd1)
+
+ This performs a "virtual" swap between your first and second hard
+drive.
+
+ *Caution:* This is effective only if DOS (or Windows) uses BIOS to
+access the swapped disks. If that OS uses a special driver for the
+disks, this probably won't work.
+
+ Another problem arises if you installed more than one set of
+DOS/Windows onto one disk, because they could be confused if there are
+more than one primary partitions for DOS/Windows. Certainly you should
+avoid doing this, but there is a solution if you do want to do so. Use
+the partition hiding/unhiding technique.
+
+ If GRUB "hides" a DOS (or Windows) partition (*note parttool::), DOS
+(or Windows) will ignore the partition. If GRUB "unhides" a DOS (or
+Windows) partition, DOS (or Windows) will detect the partition. Thus,
+if you have installed DOS (or Windows) on the first and the second
+partition of the first hard disk, and you want to boot the copy on the
+first partition, do the following:
+
+ parttool (hd0,1) hidden-
+ parttool (hd0,2) hidden+
+ set root=(hd0,1)
+ chainloader +1
+ parttool ${root} boot+
+ boot
+
+
+File: grub.info, Node: Configuration, Next: Theme file format, Prev: Booting, Up: Top
+
+6 Writing your own configuration file
+*************************************
+
+GRUB is configured using 'grub.cfg', usually located under '/boot/grub'.
+This file is quite flexible, but most users will not need to write the
+whole thing by hand.
+
+* Menu:
+
+* Simple configuration:: Recommended for most users
+* Root Identifcation Heuristics:: Summary on how the root file system is identified.
+* Shell-like scripting:: For power users and developers
+* Multi-boot manual config:: For non-standard multi-OS scenarios
+* Embedded configuration:: Embedding a configuration file into GRUB
+
+
+File: grub.info, Node: Simple configuration, Next: Root Identifcation Heuristics, Up: Configuration
+
+6.1 Simple configuration handling
+=================================
+
+The program 'grub-mkconfig' (*note Invoking grub-mkconfig::) generates
+'grub.cfg' files suitable for most cases. It is suitable for use when
+upgrading a distribution, and will discover available kernels and
+attempt to generate menu entries for them.
+
+ 'grub-mkconfig' does have some limitations. While adding extra
+custom menu entries to the end of the list can be done by editing
+'/etc/grub.d/40_custom' or creating '/boot/grub/custom.cfg', changing
+the order of menu entries or changing their titles may require making
+complex changes to shell scripts stored in '/etc/grub.d/'. This may be
+improved in the future. In the meantime, those who feel that it would
+be easier to write 'grub.cfg' directly are encouraged to do so (*note
+Booting::, and *note Shell-like scripting::), and to disable any system
+provided by their distribution to automatically run 'grub-mkconfig'.
+
+ The file '/etc/default/grub' controls the operation of
+'grub-mkconfig'. It is sourced by a shell script, and so must be valid
+POSIX shell input; normally, it will just be a sequence of 'KEY=value'
+lines, but if the value contains spaces or other special characters then
+it must be quoted. For example:
+
+ GRUB_TERMINAL_INPUT="console serial"
+
+ Valid keys in '/etc/default/grub' are as follows:
+
+'GRUB_DEFAULT'
+ The default menu entry. This may be a number, in which case it
+ identifies the Nth entry in the generated menu counted from zero,
+ or the title of a menu entry, or the special string 'saved'. Using
+ the id may be useful if you want to set a menu entry as the default
+ even though there may be a variable number of entries before it.
+
+ For example, if you have:
+
+ menuentry 'Example GNU/Linux distribution' --class gnu-linux --id example-gnu-linux {
+ ...
+ }
+
+ then you can make this the default using:
+
+ GRUB_DEFAULT=example-gnu-linux
+
+ Previously it was documented the way to use entry title. While
+ this still works it's not recommended since titles often contain
+ unstable device names and may be translated
+
+ If you set this to 'saved', then the default menu entry will be
+ that saved by 'GRUB_SAVEDEFAULT' or 'grub-set-default'. This
+ relies on the environment block, which may not be available in all
+ situations (*note Environment block::).
+
+ The default is '0'.
+
+'GRUB_SAVEDEFAULT'
+ If this option is set to 'true', then, when an entry is selected,
+ save it as a new default entry for use by future runs of GRUB. This
+ is only useful if 'GRUB_DEFAULT=saved'; it is a separate option
+ because 'GRUB_DEFAULT=saved' is useful without this option, in
+ conjunction with 'grub-set-default'. Unset by default. This
+ option relies on the environment block, which may not be available
+ in all situations (*note Environment block::).
+
+'GRUB_TIMEOUT'
+ Boot the default entry this many seconds after the menu is
+ displayed, unless a key is pressed. The default is '5'. Set to
+ '0' to boot immediately without displaying the menu, or to '-1' to
+ wait indefinitely.
+
+ If 'GRUB_TIMEOUT_STYLE' is set to 'countdown' or 'hidden', the
+ timeout is instead counted before the menu is displayed.
+
+'GRUB_TIMEOUT_STYLE'
+ If this option is unset or set to 'menu', then GRUB will display
+ the menu and then wait for the timeout set by 'GRUB_TIMEOUT' to
+ expire before booting the default entry. Pressing a key interrupts
+ the timeout.
+
+ If this option is set to 'countdown' or 'hidden', then, before
+ displaying the menu, GRUB will wait for the timeout set by
+ 'GRUB_TIMEOUT' to expire. If <ESC> or <F4> are pressed, or <SHIFT>
+ is held down during that time, it will display the menu and wait
+ for input. If a hotkey associated with a menu entry is pressed, it
+ will boot the associated menu entry immediately. If the timeout
+ expires before either of these happens, it will boot the default
+ entry. In the 'countdown' case, it will show a one-line indication
+ of the remaining time.
+
+'GRUB_DEFAULT_BUTTON'
+'GRUB_TIMEOUT_BUTTON'
+'GRUB_TIMEOUT_STYLE_BUTTON'
+'GRUB_BUTTON_CMOS_ADDRESS'
+ Variants of the corresponding variables without the '_BUTTON'
+ suffix, used to support vendor-specific power buttons. *Note
+ Vendor power-on keys::.
+
+'GRUB_DISTRIBUTOR'
+ Set by distributors of GRUB to their identifying name. This is
+ used to generate more informative menu entry titles.
+
+'GRUB_TERMINAL_INPUT'
+ Select the terminal input device. You may select multiple devices
+ here, separated by spaces.
+
+ Valid terminal input names depend on the platform, but may include
+ 'console' (native platform console), 'serial' (serial terminal),
+ 'serial_<port>' (serial terminal with explicit port selection),
+ 'at_keyboard' (PC AT keyboard), or 'usb_keyboard' (USB keyboard
+ using the HID Boot Protocol, for cases where the firmware does not
+ handle this).
+
+ The default is to use the platform's native terminal input.
+
+'GRUB_TERMINAL_OUTPUT'
+ Select the terminal output device. You may select multiple devices
+ here, separated by spaces.
+
+ Valid terminal output names depend on the platform, but may include
+ 'console' (native platform console), 'serial' (serial terminal),
+ 'serial_<port>' (serial terminal with explicit port selection),
+ 'gfxterm' (graphics-mode output), 'vga_text' (VGA text output),
+ 'mda_text' (MDA text output), 'morse' (Morse-coding using system
+ beeper) or 'spkmodem' (simple data protocol using system speaker).
+
+ 'spkmodem' is useful when no serial port is available. Connect the
+ output of sending system (where GRUB is running) to line-in of
+ receiving system (usually developer machine). On receiving system
+ compile 'spkmodem-recv' from 'util/spkmodem-recv.c' and run:
+
+ parecord --channels=1 --rate=48000 --format=s16le | ./spkmodem-recv
+
+ The default is to use the platform's native terminal output.
+
+'GRUB_TERMINAL'
+ If this option is set, it overrides both 'GRUB_TERMINAL_INPUT' and
+ 'GRUB_TERMINAL_OUTPUT' to the same value.
+
+'GRUB_SERIAL_COMMAND'
+ A command to configure the serial port when using the serial
+ console. *Note serial::. Defaults to 'serial'.
+
+'GRUB_CMDLINE_LINUX'
+ Command-line arguments to add to menu entries for the Linux kernel.
+
+'GRUB_CMDLINE_LINUX_DEFAULT'
+ Unless 'GRUB_DISABLE_RECOVERY' is set to 'true', two menu entries
+ will be generated for each Linux kernel: one default entry and one
+ entry for recovery mode. This option lists command-line arguments
+ to add only to the default menu entry, after those listed in
+ 'GRUB_CMDLINE_LINUX'.
+
+'GRUB_CMDLINE_NETBSD'
+'GRUB_CMDLINE_NETBSD_DEFAULT'
+ As 'GRUB_CMDLINE_LINUX' and 'GRUB_CMDLINE_LINUX_DEFAULT', but for
+ NetBSD.
+
+'GRUB_CMDLINE_GNUMACH'
+ As 'GRUB_CMDLINE_LINUX', but for GNU Mach.
+
+'GRUB_CMDLINE_XEN'
+'GRUB_CMDLINE_XEN_DEFAULT'
+ The values of these options are passed to Xen hypervisor Xen menu
+ entries, for all respectively normal entries.
+
+'GRUB_CMDLINE_LINUX_XEN_REPLACE'
+'GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT'
+ The values of these options replace the values of
+ 'GRUB_CMDLINE_LINUX' and 'GRUB_CMDLINE_LINUX_DEFAULT' for Linux and
+ Xen menu entries.
+
+'GRUB_EARLY_INITRD_LINUX_CUSTOM'
+'GRUB_EARLY_INITRD_LINUX_STOCK'
+ List of space-separated early initrd images to be loaded from
+ '/boot'. This is for loading things like CPU microcode, firmware,
+ ACPI tables, crypto keys, and so on. These early images will be
+ loaded in the order declared, and all will be loaded before the
+ actual functional initrd image.
+
+ 'GRUB_EARLY_INITRD_LINUX_STOCK' is for your distribution to declare
+ images that are provided by the distribution. It should not be
+ modified without understanding the consequences. They will be
+ loaded first.
+
+ 'GRUB_EARLY_INITRD_LINUX_CUSTOM' is for your custom created images.
+
+ The default stock images are as follows, though they may be
+ overridden by your distribution:
+ intel-uc.img intel-ucode.img amd-uc.img amd-ucode.img early_ucode.cpio microcode.cpio
+
+'GRUB_DISABLE_LINUX_UUID'
+ Normally, 'grub-mkconfig' will generate menu entries that use
+ universally-unique identifiers (UUIDs) to identify the root
+ filesystem to the Linux kernel, using a 'root=UUID=...' kernel
+ parameter. This is usually more reliable, but in some cases it may
+ not be appropriate. To disable the use of UUIDs, set this option
+ to 'true'.
+
+'GRUB_DISABLE_LINUX_PARTUUID'
+ If 'grub-mkconfig' cannot identify the root filesystem via its
+ universally-unique indentifier (UUID), 'grub-mkconfig' can use the
+ UUID of the partition containing the filesystem to identify the
+ root filesystem to the Linux kernel via a 'root=PARTUUID=...'
+ kernel parameter. This is not as reliable as using the filesystem
+ UUID, but is more reliable than using the Linux device names. When
+ 'GRUB_DISABLE_LINUX_PARTUUID' is set to 'false', the Linux kernel
+ version must be 2.6.37 (3.10 for systems using the MSDOS partition
+ scheme) or newer. This option defaults to 'true'. To enable the
+ use of partition UUIDs, set this option to 'false'.
+
+'GRUB_DISABLE_RECOVERY'
+ If this option is set to 'true', disable the generation of recovery
+ mode menu entries.
+
+'GRUB_DISABLE_UUID'
+ Normally, 'grub-mkconfig' will generate menu entries that use
+ universally-unique identifiers (UUIDs) to identify various
+ filesystems to search for files. This is usually more reliable,
+ but in some cases it may not be appropriate. To disable this use
+ of UUIDs, set this option to 'true'. Setting this option to
+ 'true', will also set the options 'GRUB_DISABLE_LINUX_UUID' and
+ 'GRUB_DISABLE_LINUX_PARTUUID' to 'true', unless they have been
+ explicilty set to 'false'.
+
+'GRUB_VIDEO_BACKEND'
+ If graphical video support is required, either because the
+ 'gfxterm' graphical terminal is in use or because
+ 'GRUB_GFXPAYLOAD_LINUX' is set, then 'grub-mkconfig' will normally
+ load all available GRUB video drivers and use the one most
+ appropriate for your hardware. If you need to override this for
+ some reason, then you can set this option.
+
+ After 'grub-install' has been run, the available video drivers are
+ listed in '/boot/grub/video.lst'.
+
+'GRUB_GFXMODE'
+ Set the resolution used on the 'gfxterm' graphical terminal. Note
+ that you can only use modes which your graphics card supports via
+ VESA BIOS Extensions (VBE), so for example native LCD panel
+ resolutions may not be available. The default is 'auto', which
+ tries to select a preferred resolution. *Note gfxmode::.
+
+'GRUB_BACKGROUND'
+ Set a background image for use with the 'gfxterm' graphical
+ terminal. The value of this option must be a file readable by GRUB
+ at boot time, and it must end with '.png', '.tga', '.jpg', or
+ '.jpeg'. The image will be scaled if necessary to fit the screen.
+
+'GRUB_THEME'
+ Set a theme for use with the 'gfxterm' graphical terminal.
+
+'GRUB_GFXPAYLOAD_LINUX'
+ Set to 'text' to force the Linux kernel to boot in normal text
+ mode, 'keep' to preserve the graphics mode set using
+ 'GRUB_GFXMODE', 'WIDTHxHEIGHT'['xDEPTH'] to set a particular
+ graphics mode, or a sequence of these separated by commas or
+ semicolons to try several modes in sequence. *Note gfxpayload::.
+
+ Depending on your kernel, your distribution, your graphics card,
+ and the phase of the moon, note that using this option may cause
+ GNU/Linux to suffer from various display problems, particularly
+ during the early part of the boot sequence. If you have problems,
+ set this option to 'text' and GRUB will tell Linux to boot in
+ normal text mode.
+
+'GRUB_DISABLE_OS_PROBER'
+ The 'grub-mkconfig' has a feature to use the external 'os-prober'
+ program to discover other operating systems installed on the same
+ machine and generate appropriate menu entries for them. It is
+ disabled by default since automatic and silent execution of
+ 'os-prober', and creating boot entries based on that data, is a
+ potential attack vector. Set this option to 'false' to enable this
+ feature in the 'grub-mkconfig' command.
+
+'GRUB_OS_PROBER_SKIP_LIST'
+ List of space-separated FS UUIDs of filesystems to be ignored from
+ os-prober output. For efi chainloaders it's <UUID>@<EFI FILE>
+
+'GRUB_DISABLE_SUBMENU'
+ Normally, 'grub-mkconfig' will generate top level menu entry for
+ the kernel with highest version number and put all other found
+ kernels or alternative menu entries for recovery mode in submenu.
+ For entries returned by 'os-prober' first entry will be put on top
+ level and all others in submenu. If this option is set to 'true',
+ flat menu with all entries on top level will be generated instead.
+ Changing this option will require changing existing values of
+ 'GRUB_DEFAULT', 'fallback' (*note fallback::) and 'default' (*note
+ default::) environment variables as well as saved default entry
+ using 'grub-set-default' and value used with 'grub-reboot'.
+
+'GRUB_ENABLE_CRYPTODISK'
+ If set to 'y', 'grub-mkconfig' and 'grub-install' will check for
+ encrypted disks and generate additional commands needed to access
+ them during boot. Note that in this case unattended boot is not
+ possible because GRUB will wait for passphrase to unlock encrypted
+ container.
+
+'GRUB_INIT_TUNE'
+ Play a tune on the speaker when GRUB starts. This is particularly
+ useful for users unable to see the screen. The value of this
+ option is passed directly to *note play::.
+
+'GRUB_BADRAM'
+ If this option is set, GRUB will issue a *note badram:: command to
+ filter out specified regions of RAM.
+
+'GRUB_PRELOAD_MODULES'
+ This option may be set to a list of GRUB module names separated by
+ spaces. Each module will be loaded as early as possible, at the
+ start of 'grub.cfg'.
+
+ The following options are still accepted for compatibility with
+existing configurations, but have better replacements:
+
+'GRUB_HIDDEN_TIMEOUT'
+ Wait this many seconds before displaying the menu. If <ESC> or
+ <F4> are pressed, or <SHIFT> is held down during that time, display
+ the menu and wait for input according to 'GRUB_TIMEOUT'. If a
+ hotkey associated with a menu entry is pressed, boot the associated
+ menu entry immediately. If the timeout expires before either of
+ these happens, display the menu for the number of seconds specified
+ in 'GRUB_TIMEOUT' before booting the default entry.
+
+ If you set 'GRUB_HIDDEN_TIMEOUT', you should also set
+ 'GRUB_TIMEOUT=0' so that the menu is not displayed at all unless
+ <ESC> or <F4> are pressed, or <SHIFT> is held down.
+
+ This option is unset by default, and is deprecated in favour of the
+ less confusing 'GRUB_TIMEOUT_STYLE=countdown' or
+ 'GRUB_TIMEOUT_STYLE=hidden'.
+
+'GRUB_HIDDEN_TIMEOUT_QUIET'
+ In conjunction with 'GRUB_HIDDEN_TIMEOUT', set this to 'true' to
+ suppress the verbose countdown while waiting for a key to be
+ pressed before displaying the menu.
+
+ This option is unset by default, and is deprecated in favour of the
+ less confusing 'GRUB_TIMEOUT_STYLE=countdown'.
+
+'GRUB_HIDDEN_TIMEOUT_BUTTON'
+ Variant of 'GRUB_HIDDEN_TIMEOUT', used to support vendor-specific
+ power buttons. *Note Vendor power-on keys::.
+
+ This option is unset by default, and is deprecated in favour of the
+ less confusing 'GRUB_TIMEOUT_STYLE=countdown' or
+ 'GRUB_TIMEOUT_STYLE=hidden'.
+
+ For more detailed customisation of 'grub-mkconfig''s output, you may
+edit the scripts in '/etc/grub.d' directly. '/etc/grub.d/40_custom' is
+particularly useful for adding entire custom menu entries; simply type
+the menu entries you want to add at the end of that file, making sure to
+leave at least the first two lines intact.
+
+
+File: grub.info, Node: Root Identifcation Heuristics, Next: Shell-like scripting, Prev: Simple configuration, Up: Configuration
+
+6.2 Root Identifcation Heuristics
+=================================
+
+If the target operating system uses the Linux kernel, 'grub-mkconfig'
+attempts to identify the root file system via a heuristic algoirthm.
+This algorithm selects the identification method of the root file system
+by considering three factors. The first is if an initrd for the target
+operating system is also present. The second is
+'GRUB_DISABLE_LINUX_UUID' and if set to 'true', prevents 'grub-mkconfig'
+from identifying the root file system by its UUID. The third is
+'GRUB_DISABLE_LINUX_PARTUUID' and if set to 'true', prevents
+'grub-mkconfig' from identifying the root file system via the UUID of
+its enclosing partition. If the variables are assigned any other value,
+that value is considered equivalent to 'false'. The variables are also
+considered to be set to 'false' if they are not set.
+
+ When booting, the Linux kernel will delegate the task of mounting the
+root filesystem to the initrd. Most initrd images determine the root
+file system by checking the Linux kernel's command-line for the 'root'
+key and use its value as the identification method of the root file
+system. To improve the reliability of booting, most initrd images also
+allow the root file system to be identified by its UUID. Because of this
+behavior, the 'grub-mkconfig' command will set 'root' to 'root=UUID=...'
+to provide the initrd with the filesystem UUID of the root file system.
+
+ If no initrd is detected or 'GRUB_DISABLE_LINUX_UUID' is set to
+'true' then 'grub-command' will identify the root filesystem by setting
+the kernel command-line variable 'root' to 'root=PARTUUID=...' unless
+'GRUB_DISABLE_LINUX_PARTUUID' is also set to 'true'. If
+'GRUB_DISABLE_LINUX_PARTUUID' is also set to 'true', 'grub-command' will
+identify by its Linux device name.
+
+ The following table summarizes the behavior of the 'grub-mkconfig'
+command.
+
+Initrd GRUB_DISABLE_LINUX_PARTUUID GRUB_DISABLE_LINUX_UUID Linux Root
+detected Set To Set To ID Method
+--------------------------------------------------------------------------------
+false false false part UUID
+false false true part UUID
+false true false dev name
+false true true dev name
+true false false fs UUID
+true false true part UUID
+true true false fs UUID
+true true true dev name
+
+ Remember, 'GRUB_DISABLE_LINUX_PARTUUID' and 'GRUB_DISABLE_LINUX_UUID'
+are also considered to be set to 'false' when they are unset.
+
+
+File: grub.info, Node: Shell-like scripting, Next: Multi-boot manual config, Prev: Root Identifcation Heuristics, Up: Configuration
+
+6.3 Writing full configuration files directly
+=============================================
+
+'grub.cfg' is written in GRUB's built-in scripting language, which has a
+syntax quite similar to that of GNU Bash and other Bourne shell
+derivatives.
+
+Words
+=====
+
+A "word" is a sequence of characters considered as a single unit by
+GRUB. Words are separated by "metacharacters", which are the following
+plus space, tab, and newline:
+
+ { } | & $ ; < >
+
+ Quoting may be used to include metacharacters in words; see below.
+
+Reserved words
+==============
+
+Reserved words have a special meaning to GRUB. The following words are
+recognised as reserved when unquoted and either the first word of a
+simple command or the third word of a 'for' command:
+
+ ! [[ ]] { }
+ case do done elif else esac fi for function
+ if in menuentry select then time until while
+
+ Not all of these reserved words have a useful purpose yet; some are
+reserved for future expansion.
+
+Quoting
+=======
+
+Quoting is used to remove the special meaning of certain characters or
+words. It can be used to treat metacharacters as part of a word, to
+prevent reserved words from being recognised as such, and to prevent
+variable expansion.
+
+ There are three quoting mechanisms: the escape character, single
+quotes, and double quotes.
+
+ A non-quoted backslash (\) is the "escape character". It preserves
+the literal value of the next character that follows, with the exception
+of newline.
+
+ Enclosing characters in single quotes preserves the literal value of
+each character within the quotes. A single quote may not occur between
+single quotes, even when preceded by a backslash.
+
+ Enclosing characters in double quotes preserves the literal value of
+all characters within the quotes, with the exception of '$' and '\'.
+The '$' character retains its special meaning within double quotes. The
+backslash retains its special meaning only when followed by one of the
+following characters: '$', '"', '\', or newline. A backslash-newline
+pair is treated as a line continuation (that is, it is removed from the
+input stream and effectively ignored(1) (*note Shell-like
+scripting-Footnote-1::)). A double quote may be quoted within double
+quotes by preceding it with a backslash.
+
+Variable expansion
+==================
+
+The '$' character introduces variable expansion. The variable name to
+be expanded may be enclosed in braces, which are optional but serve to
+protect the variable to be expanded from characters immediately
+following it which could be interpreted as part of the name.
+
+ Normal variable names begin with an alphabetic character, followed by
+zero or more alphanumeric characters. These names refer to entries in
+the GRUB environment (*note Environment::).
+
+ Positional variable names consist of one or more digits. They
+represent parameters passed to function calls, with '$1' representing
+the first parameter, and so on.
+
+ The special variable name '?' expands to the exit status of the most
+recently executed command. When positional variable names are active,
+other special variable names '@', '*' and '#' are defined and they
+expand to all positional parameters with necessary quoting, positional
+parameters without any quoting, and positional parameter count
+respectively.
+
+Comments
+========
+
+A word beginning with '#' causes that word and all remaining characters
+on that line to be ignored.
+
+Simple commands
+===============
+
+A "simple command" is a sequence of words separated by spaces or tabs
+and terminated by a semicolon or a newline. The first word specifies
+the command to be executed. The remaining words are passed as arguments
+to the invoked command.
+
+ The return value of a simple command is its exit status. If the
+reserved word '!' precedes the command, then the return value is instead
+the logical negation of the command's exit status.
+
+Compound commands
+=================
+
+A "compound command" is one of the following:
+
+for NAME in WORD ...; do LIST; done
+ The list of words following 'in' is expanded, generating a list of
+ items. The variable NAME is set to each element of this list in
+ turn, and LIST is executed each time. The return value is the exit
+ status of the last command that executes. If the expansion of the
+ items following 'in' results in an empty list, no commands are
+ executed, and the return status is 0.
+
+if LIST; then LIST; [elif LIST; then LIST;] ... [else LIST;] fi
+ The 'if' LIST is executed. If its exit status is zero, the 'then'
+ LIST is executed. Otherwise, each 'elif' LIST is executed in turn,
+ and if its exit status is zero, the corresponding 'then' LIST is
+ executed and the command completes. Otherwise, the 'else' LIST is
+ executed, if present. The exit status is the exit status of the
+ last command executed, or zero if no condition tested true.
+
+while COND; do LIST; done
+until COND; do LIST; done
+ The 'while' command continuously executes the 'do' LIST as long as
+ the last command in COND returns an exit status of zero. The
+ 'until' command is identical to the 'while' command, except that
+ the test is negated; the 'do' LIST is executed as long as the last
+ command in COND returns a non-zero exit status. The exit status of
+ the 'while' and 'until' commands is the exit status of the last
+ 'do' LIST command executed, or zero if none was executed.
+
+function NAME { COMMAND; ... }
+ This defines a function named NAME. The "body" of the function is
+ the list of commands within braces, each of which must be
+ terminated with a semicolon or a newline. This list of commands
+ will be executed whenever NAME is specified as the name of a simple
+ command. Function definitions do not affect the exit status in
+ '$?'. When executed, the exit status of a function is the exit
+ status of the last command executed in the body.
+
+menuentry TITLE ['--class=class' ...] ['--users=users'] ['--unrestricted'] ['--hotkey=key'] ['--id=id'] { COMMAND; ... }
+ *Note menuentry::.
+
+Built-in Commands
+=================
+
+Some built-in commands are also provided by GRUB script to help script
+writers perform actions that are otherwise not possible. For example,
+these include commands to jump out of a loop without fully completing
+it, etc.
+
+break ['n']
+ Exit from within a 'for', 'while', or 'until' loop. If 'n' is
+ specified, break 'n' levels. 'n' must be greater than or equal to
+ 1. If 'n' is greater than the number of enclosing loops, all
+ enclosing loops are exited. The return value is 0 unless 'n' is
+ not greater than or equal to 1.
+
+continue ['n']
+ Resume the next iteration of the enclosing 'for', 'while' or
+ 'until' loop. If 'n' is specified, resume at the 'n'th enclosing
+ loop. 'n' must be greater than or equal to 1. If 'n' is greater
+ than the number of enclosing loops, the last enclosing loop (the
+ "top-level" loop) is resumed. The return value is 0 unless 'n' is
+ not greater than or equal to 1.
+
+return ['n']
+ Causes a function to exit with the return value specified by 'n'.
+ If 'n' is omitted, the return status is that of the last command
+ executed in the function body. If used outside a function the
+ return status is false.
+
+setparams ['arg'] ...
+ Replace positional parameters starting with '$1' with arguments to
+ 'setparams'.
+
+shift ['n']
+ The positional parameters from 'n'+1 ... are renamed to '$1'....
+ Parameters represented by the numbers '$#' down to '$#'-'n'+1 are
+ unset. 'n' must be a non-negative number less than or equal to
+ '$#'. If 'n' is 0, no parameters are changed. If 'n' is not
+ given, it is assumed to be 1. If 'n' is greater than '$#', the
+ positional parameters are not changed. The return status is
+ greater than zero if 'n' is greater than '$#' or less than zero;
+ otherwise 0.
+
+
+File: grub.info, Node: Shell-like scripting-Footnotes, Up: Shell-like scripting
+
+ (1) Currently a backslash-newline pair within a variable name is not
+handled properly, so use this feature with some care.
+
+
+File: grub.info, Node: Multi-boot manual config, Next: Embedded configuration, Prev: Shell-like scripting, Up: Configuration
+
+6.4 Multi-boot manual config
+============================
+
+Currently autogenerating config files for multi-boot environments
+depends on os-prober and has several shortcomings. Due to that it is
+disabled by default. It is advised to use the power of GRUB syntax and
+do it yourself. A possible configuration is detailed here, feel free to
+adjust to your needs.
+
+ First create a separate GRUB partition, big enough to hold GRUB. Some
+of the following entries show how to load OS installer images from this
+same partition, for that you obviously need to make the partition large
+enough to hold those images as well. Mount this partition on/mnt/boot
+and disable GRUB in all OSes and manually install self-compiled latest
+GRUB with:
+
+ 'grub-install --boot-directory=/mnt/boot /dev/sda'
+
+ In all the OSes install GRUB tools but disable installing GRUB in
+bootsector, so you'll have menu.lst and grub.cfg available for use.
+Also disable os-prober use by setting:
+
+ 'GRUB_DISABLE_OS_PROBER=true'
+
+ in /etc/default/grub
+
+ Then write a grub.cfg (/mnt/boot/grub/grub.cfg):
+
+
+ menuentry "OS using grub2" {
+ insmod xfs
+ search --set=root --label OS1 --hint hd0,msdos8
+ configfile /boot/grub/grub.cfg
+ }
+
+ menuentry "OS using grub2-legacy" {
+ insmod ext2
+ search --set=root --label OS2 --hint hd0,msdos6
+ legacy_configfile /boot/grub/menu.lst
+ }
+
+ menuentry "Windows XP" {
+ insmod ntfs
+ search --set=root --label WINDOWS_XP --hint hd0,msdos1
+ ntldr /ntldr
+ }
+
+ menuentry "Windows 7" {
+ insmod ntfs
+ search --set=root --label WINDOWS_7 --hint hd0,msdos2
+ ntldr /bootmgr
+ }
+
+ menuentry "FreeBSD" {
+ insmod zfs
+ search --set=root --label freepool --hint hd0,msdos7
+ kfreebsd /freebsd@/boot/kernel/kernel
+ kfreebsd_module_elf /freebsd@/boot/kernel/opensolaris.ko
+ kfreebsd_module_elf /freebsd@/boot/kernel/zfs.ko
+ kfreebsd_module /freebsd@/boot/zfs/zpool.cache type=/boot/zfs/zpool.cache
+ set kFreeBSD.vfs.root.mountfrom=zfs:freepool/freebsd
+ set kFreeBSD.hw.psm.synaptics_support=1
+ }
+
+ menuentry "experimental GRUB" {
+ search --set=root --label GRUB --hint hd0,msdos5
+ multiboot /experimental/grub/i386-pc/core.img
+ }
+
+ menuentry "Fedora 16 installer" {
+ search --set=root --label GRUB --hint hd0,msdos5
+ linux /fedora/vmlinuz lang=en_US keymap=sg resolution=1280x800
+ initrd /fedora/initrd.img
+ }
+
+ menuentry "Fedora rawhide installer" {
+ search --set=root --label GRUB --hint hd0,msdos5
+ linux /fedora/vmlinuz repo=ftp://mirror.switch.ch/mirror/fedora/linux/development/rawhide/x86_64 lang=en_US keymap=sg resolution=1280x800
+ initrd /fedora/initrd.img
+ }
+
+ menuentry "Debian sid installer" {
+ search --set=root --label GRUB --hint hd0,msdos5
+ linux /debian/dists/sid/main/installer-amd64/current/images/hd-media/vmlinuz
+ initrd /debian/dists/sid/main/installer-amd64/current/images/hd-media/initrd.gz
+ }
+
+
+ Notes:
+ * Argument to search after -label is FS LABEL. You can also use UUIDs
+ with -fs-uuid UUID instead of -label LABEL. You could also use
+ direct 'root=hd0,msdosX' but this is not recommended due to device
+ name instability.
+
+
+File: grub.info, Node: Embedded configuration, Prev: Multi-boot manual config, Up: Configuration
+
+6.5 Embedding a configuration file into GRUB
+============================================
+
+GRUB supports embedding a configuration file directly into the core
+image, so that it is loaded before entering normal mode. This is
+useful, for example, when it is not straightforward to find the real
+configuration file, or when you need to debug problems with loading that
+file. 'grub-install' uses this feature when it is not using BIOS disk
+functions or when installing to a different disk from the one containing
+'/boot/grub', in which case it needs to use the 'search' command (*note
+search::) to find '/boot/grub'.
+
+ To embed a configuration file, use the '-c' option to 'grub-mkimage'.
+The file is copied into the core image, so it may reside anywhere on the
+file system, and may be removed after running 'grub-mkimage'.
+
+ After the embedded configuration file (if any) is executed, GRUB will
+load the 'normal' module (*note normal::), which will then read the real
+configuration file from '$prefix/grub.cfg'. By this point, the 'root'
+variable will also have been set to the root device name. For example,
+'prefix' might be set to '(hd0,1)/boot/grub', and 'root' might be set to
+'hd0,1'. Thus, in most cases, the embedded configuration file only
+needs to set the 'prefix' and 'root' variables, and then drop through to
+GRUB's normal processing. A typical example of this might look like
+this:
+
+ search.fs_uuid 01234567-89ab-cdef-0123-456789abcdef root
+ set prefix=($root)/boot/grub
+
+ (The 'search_fs_uuid' module must be included in the core image for
+this example to work.)
+
+ In more complex cases, it may be useful to read other configuration
+files directly from the embedded configuration file. This allows such
+things as reading files not called 'grub.cfg', or reading files from a
+directory other than that where GRUB's loadable modules are installed.
+To do this, include the 'configfile' and 'normal' modules in the core
+image, and embed a configuration file that uses the 'configfile' command
+to load another file. The following example of this also requires the
+'echo', 'search_label', and 'test' modules to be included in the core
+image:
+
+ search.fs_label grub root
+ if [ -e /boot/grub/example/test1.cfg ]; then
+ set prefix=($root)/boot/grub
+ configfile /boot/grub/example/test1.cfg
+ else
+ if [ -e /boot/grub/example/test2.cfg ]; then
+ set prefix=($root)/boot/grub
+ configfile /boot/grub/example/test2.cfg
+ else
+ echo "Could not find an example configuration file!"
+ fi
+ fi
+
+ The embedded configuration file may not contain menu entries
+directly, but may only read them from elsewhere using 'configfile'.
+
+
+File: grub.info, Node: Theme file format, Next: Network, Prev: Configuration, Up: Top
+
+7 Theme file format
+*******************
+
+7.1 Introduction
+================
+
+The GRUB graphical menu supports themes that can customize the layout
+and appearance of the GRUB boot menu. The theme is configured through a
+plain text file that specifies the layout of the various GUI components
+(including the boot menu, timeout progress bar, and text messages) as
+well as the appearance using colors, fonts, and images. Example is
+available in docs/example_theme.txt
+
+7.2 Theme Elements
+==================
+
+7.2.1 Colors
+------------
+
+Colors can be specified in several ways:
+
+ * HTML-style "#RRGGBB" or "#RGB" format, where *R*, *G*, and *B* are
+ hexadecimal digits (e.g., "#8899FF")
+ * as comma-separated decimal RGB values (e.g., "128, 128, 255")
+ * with "SVG 1.0 color names" (e.g., "cornflowerblue") which must be
+ specified in lowercase.
+
+7.2.2 Fonts
+-----------
+
+The fonts GRUB uses "PFF2 font format" bitmap fonts. Fonts are
+specified with full font names. Currently there is no provision for a
+preference list of fonts, or deriving one font from another. Fonts are
+loaded with the "loadfont" command in GRUB (*note loadfont::). To see
+the list of loaded fonts, execute the "lsfonts" command (*note
+lsfonts::). If there are too many fonts to fit on screen, do "set
+pager=1" before executing "lsfonts".
+
+7.2.3 Progress Bar
+------------------
+
+Figure 7.1
+
+Figure 7.2
+
+Progress bars are used to display the remaining time before GRUB boots
+the default menu entry. To create a progress bar that will display the
+remaining time before automatic boot, simply create a "progress_bar"
+component with the id "__timeout__". This indicates to GRUB that the
+progress bar should be updated as time passes, and it should be made
+invisible if the countdown to automatic boot is interrupted by the user.
+
+ Progress bars may optionally have text displayed on them. This text
+is controlled by variable "text" which contains a printf template with
+the only argument %d is the number of seconds remaining. Additionally
+special values "@TIMEOUT_NOTIFICATION_SHORT@",
+"@TIMEOUT_NOTIFICATION_MIDDLE@", "@TIMEOUT_NOTIFICATION_LONG@" are
+replaced with standard and translated templates.
+
+7.2.4 Circular Progress Indicator
+---------------------------------
+
+The circular progress indicator functions similarly to the progress bar.
+When given an id of "__timeout__", GRUB updates the circular progress
+indicator's value to indicate the time remaining. For the circular
+progress indicator, there are two images used to render it: the *center*
+image, and the *tick* image. The center image is rendered in the center
+of the component, while the tick image is used to render each mark along
+the circumference of the indicator.
+
+7.2.5 Labels
+------------
+
+Text labels can be placed on the boot screen. The font, color, and
+horizontal alignment can be specified for labels. If a label is given
+the id "__timeout__", then the "text" property for that label is also
+updated with a message informing the user of the number of seconds
+remaining until automatic boot. This is useful in case you want the
+text displayed somewhere else instead of directly on the progress bar.
+
+7.2.6 Boot Menu
+---------------
+
+The boot menu where GRUB displays the menu entries from the "grub.cfg"
+file. It is a list of items, where each item has a title and an
+optional icon. The icon is selected based on the *classes* specified
+for the menu entry. If there is a PNG file named "myclass.png" in the
+"grub/themes/icons" directory, it will be displayed for items which have
+the class *myclass*. The boot menu can be customized in several ways,
+such as the font and color used for the menu entry title, and by
+specifying styled boxes for the menu itself and for the selected item
+highlight.
+
+7.2.7 Styled Boxes
+------------------
+
+One of the most important features for customizing the layout is the use
+of *styled boxes*. A styled box is composed of 9 rectangular (and
+potentially empty) regions, which are used to seamlessly draw the styled
+box on screen:
+
+Northwest (nw) North (n) Northeast (ne)
+West (w) Center (c) East (e)
+Southwest (sw) South (s) Southeast (se)
+
+ To support any size of box on screen, the center slice and the slices
+for the top, bottom, and sides are all scaled to the correct size for
+the component on screen, using the following rules:
+
+ 1. The edge slices (north, south, east, and west) are scaled in the
+ direction of the edge they are adjacent to. For instance, the west
+ slice is scaled vertically.
+ 2. The corner slices (northwest, northeast, southeast, and southwest)
+ are not scaled.
+ 3. The center slice is scaled to fill the remaining space in the
+ middle.
+
+ As an example of how an image might be sliced up, consider the styled
+box used for a terminal view.
+
+Figure 7.3
+
+7.2.8 Creating Styled Box Images
+--------------------------------
+
+The Inkscape_ scalable vector graphics editor is a very useful tool for
+creating styled box images. One process that works well for slicing a
+drawing into the necessary image slices is:
+
+ 1. Create or open the drawing you'd like use.
+ 2. Create a new layer on the top of the layer stack. Make it visible.
+ Select this layer as the current layer.
+ 3. Draw 9 rectangles on your drawing where you'd like the slices to
+ be. Clear the fill option, and set the stroke to 1 pixel wide
+ solid stroke. The corners of the slices must meet precisely; if it
+ is off by a single pixel, it will probably be evident when the
+ styled box is rendered in the GRUB menu. You should probably go to
+ File | Document Properties | Grids and enable a grid or create a
+ guide (click on one of the rulers next to the drawing and drag over
+ the drawing; release the mouse button to place the guide) to help
+ place the rectangles precisely.
+ 4. Right click on the center slice rectangle and choose Object
+ Properties. Change the "Id" to "slice_c" and click Set. Repeat
+ this for the remaining 8 rectangles, giving them Id values of
+ "slice_n", "slice_ne", "slice_e", and so on according to the
+ location.
+ 5. Save the drawing.
+ 6. Select all the slice rectangles. With the slice layer selected,
+ you can simply press Ctrl+A to select all rectangles. The status
+ bar should indicate that 9 rectangles are selected.
+ 7. Click the layer hide icon for the slice layer in the layer palette.
+ The rectangles will remain selected, even though they are hidden.
+ 8. Choose File | Export Bitmap and check the *Batch export 9 selected
+ objects* box. Make sure that *Hide all except selected* is
+ unchecked. click *Export*. This will create PNG files in the same
+ directory as the drawing, named after the slices. These can now be
+ used for a styled box in a GRUB theme.
+
+7.3 Theme File Manual
+=====================
+
+The theme file is a plain text file. Lines that begin with "#" are
+ignored and considered comments. (Note: This may not be the case if the
+previous line ended where a value was expected.)
+
+ The theme file contains two types of statements:
+ 1. Global properties.
+ 2. Component construction.
+
+7.3.1 Global Properties
+-----------------------
+
+7.3.2 Format
+------------
+
+Global properties are specified with the simple format:
+ * name1: value1
+ * name2: "value which may contain spaces"
+ * name3: #88F
+
+ In this example, name3 is assigned a color value.
+
+7.3.3 Global Property List
+--------------------------
+
+title-text Specifies the text to display at the top
+ center of the screen as a title.
+title-font Defines the font used for the title
+ message at the top of the screen.
+title-color Defines the color of the title message.
+message-font Currently unused. Left for backward
+ compatibility.
+message-color Currently unused. Left for backward
+ compatibility.
+message-bg-color Currently unused. Left for backward
+ compatibility.
+desktop-image Specifies the image to use as the
+ background. It will be scaled to fit the
+ screen size or proportionally scaled
+ depending on the scale method.
+desktop-image-scale-methodSpecifies the scaling method for the
+ *desktop-image*. Options are "stretch",
+ "crop", "padding", "fitwidth",
+ "fitheight". "stretch" for fitting the
+ screen size. Otherwise it is
+ proportional scaling of a part of
+ *desktop-image* to the part of the
+ screen. "crop" part of the
+ *desktop-image* will be proportionally
+ scaled to fit the screen sizes.
+ "padding" the entire *desktop-image* will
+ be contained on the screen. "fitwidth"
+ for fitting the *desktop-image*'s width
+ with screen width. "fitheight" for
+ fitting the *desktop-image*'s height with
+ the screen height. Default is "stretch".
+desktop-image-h-align Specifies the horizontal alignment of the
+ *desktop-image* if
+ *desktop-image-scale-method* isn't equeal
+ to "stretch". Options are "left",
+ "center", "right". Default is "center".
+desktop-image-v-align Specifies the vertical alignment of the
+ *desktop-image* if
+ *desktop-image-scale-method* isn't equeal
+ to "stretch". Options are "top",
+ "center", "bottom". Default is "center".
+desktop-color Specifies the color for the background if
+ *desktop-image* is not specified.
+terminal-box Specifies the file name pattern for the
+ styled box slices used for the command
+ line terminal window. For example,
+ "terminal-box: terminal_*.png" will use
+ the images "terminal_c.png" as the center
+ area, "terminal_n.png" as the north (top)
+ edge, "terminal_nw.png" as the northwest
+ (upper left) corner, and so on. If the
+ image for any slice is not found, it will
+ simply be left empty.
+terminal-border Specifies the border width of the
+ terminal window.
+terminal-left Specifies the left coordinate of the
+ terminal window.
+terminal-top Specifies the top coordinate of the
+ terminal window.
+terminal-width Specifies the width of the terminal
+ window.
+terminal-height Specifies the height of the terminal
+ window.
+
+7.3.4 Component Construction
+----------------------------
+
+Greater customizability comes is provided by components. A tree of
+components forms the user interface. *Containers* are components that
+can contain other components, and there is always a single root
+component which is an instance of a *canvas* container.
+
+ Components are created in the theme file by prefixing the type of
+component with a '+' sign:
+
+ ' + label { text="GRUB" font="aqui 11" color="#8FF" } '
+
+ properties of a component are specified as "name = value" (whitespace
+surrounding tokens is optional and is ignored) where *value* may be:
+ * a single word (e.g., "align = center", "color = #FF8080"),
+ * a quoted string (e.g., "text = "Hello, World!""), or
+ * a tuple (e.g., "preferred_size = (120, 80)").
+
+7.3.5 Component List
+--------------------
+
+The following is a list of the components and the properties they
+support.
+
+ * label A label displays a line of text.
+
+ Properties:
+ id Set to "__timeout__" to display the time elapsed
+ to an automatical boot of the default entry.
+ text The text to display. If "id" is set to
+ "__timeout__" and no "text" property is set then
+ the amount of seconds will be shown. If set to
+ "@KEYMAP_SHORT@", "@KEYMAP_MIDDLE@" or
+ "@KEYMAP_LONG@" then predefined hotkey
+ information will be shown.
+ font The font to use for text display.
+ color The color of the text.
+ align The horizontal alignment of the text within the
+ component. Options are "left", "center" and
+ "right".
+ visible Set to "false" to hide the label.
+
+ * image A component that displays an image. The image is scaled to
+ fit the component.
+
+ Properties:
+
+ file The full path to the image file to load.
+
+ * progress_bar Displays a horizontally oriented progress bar. It can
+ be rendered using simple solid filled rectangles, or using a pair
+ of pixmap styled boxes.
+
+ Properties:
+
+ id Set to "__timeout__" to display the time elapsed
+ to an automatical boot of the default entry.
+ fg_color The foreground color for plain solid color
+ rendering.
+ bg_color The background color for plain solid color
+ rendering.
+ border_color The border color for plain solid color
+ rendering.
+ text_color The text color.
+ bar_style The styled box specification for the frame of
+ the progress bar. Example:
+ "progress_frame_*.png" If the value is equal to
+ "highlight_style" then no styled boxes will be
+ shown.
+ highlight_styleThe styled box specification for the highlighted
+ region of the progress bar. This box will be
+ used to paint just the highlighted region of the
+ bar, and will be increased in size as the bar
+ nears completion. Example: "progress_hl_*.png".
+ If the value is equal to "bar_style" then no
+ styled boxes will be shown.
+ highlight_overlayIf this option is set to "true" then the
+ highlight box side slices (every slice except
+ the center slice) will overlay the frame box
+ side slices. And the center slice of the
+ highlight box can move all the way (from top to
+ bottom), being drawn on the center slice of the
+ frame box. That way we can make a progress bar
+ with round-shaped edges so there won't be a free
+ space from the highlight to the frame in top and
+ bottom scrollbar positions. Default is "false".
+ font The font to use for progress bar.
+ text The text to display on the progress bar. If the
+ progress bar's ID is set to "__timeout__" and
+ the value of this property is set to
+ "@TIMEOUT_NOTIFICATION_SHORT@",
+ "@TIMEOUT_NOTIFICATION_MIDDLE@" or
+ "@TIMEOUT_NOTIFICATION_LONG@", then GRUB will
+ update this property with an informative message
+ as the timeout approaches.
+
+ * circular_progress Displays a circular progress indicator. The
+ appearance of this component is determined by two images: the
+ *center* image and the *tick* image. The center image is generally
+ larger and will be drawn in the center of the component. Around
+ the circumference of a circle within the component, the tick image
+ will be drawn a certain number of times, depending on the
+ properties of the component.
+
+ Properties:
+
+ id Set to "__timeout__" to display the time
+ elapsed to an automatical boot of the
+ default entry.
+ center_bitmap The file name of the image to draw in the
+ center of the component.
+ tick_bitmap The file name of the image to draw for
+ the tick marks.
+ num_ticks The number of ticks that make up a full
+ circle.
+ ticks_disappear Boolean value indicating whether tick
+ marks should progressively appear, or
+ progressively disappear as *value*
+ approaches *end*. Specify "true" or
+ "false". Default is "false".
+ start_angle The position of the first tick mark to
+ appear or disappear. Measured in
+ "parrots", 1 "parrot" = 1 / 256 of the
+ full circle. Use values "xxx deg" or
+ "xxx \xc2\xb0" to set the angle in
+ degrees.
+
+ * boot_menu Displays the GRUB boot menu. It allows selecting items
+ and executing them.
+
+ Properties:
+
+ item_font The font to use for the menu item
+ titles.
+ selected_item_font The font to use for the selected
+ menu item, or "inherit" (the
+ default) to use "item_font" for
+ the selected menu item as well.
+ item_color The color to use for the menu item
+ titles.
+ selected_item_color The color to use for the selected
+ menu item, or "inherit" (the
+ default) to use "item_color" for
+ the selected menu item as well.
+ icon_width The width of menu item icons.
+ Icons are scaled to the specified
+ size.
+ icon_height The height of menu item icons.
+ item_height The height of each menu item in
+ pixels.
+ item_padding The amount of space in pixels to
+ leave on each side of the menu
+ item contents.
+ item_icon_space The space between an item's icon
+ and the title text, in pixels.
+ item_spacing The amount of space to leave
+ between menu items, in pixels.
+ menu_pixmap_style The image file pattern for the
+ menu frame styled box. Example:
+ "menu_*.png" (this will use images
+ such as "menu_c.png",
+ "menu_w.png", 'menu_nw.png", etc.)
+ item_pixmap_style The image file pattern for the
+ item styled box.
+ selected_item_pixmap_style The image file pattern for the
+ selected item highlight styled
+ box.
+ scrollbar Boolean value indicating whether
+ the scroll bar should be drawn if
+ the frame and thumb styled boxes
+ are configured.
+ scrollbar_frame The image file pattern for the
+ entire scroll bar. Example:
+ "scrollbar_*.png"
+ scrollbar_thumb The image file pattern for the
+ scroll bar thumb (the part of the
+ scroll bar that moves as scrolling
+ occurs). Example:
+ "scrollbar_thumb_*.png"
+ scrollbar_thumb_overlay If this option is set to "true"
+ then the scrollbar thumb side
+ slices (every slice except the
+ center slice) will overlay the
+ scrollbar frame side slices. And
+ the center slice of the
+ scrollbar_thumb can move all the
+ way (from top to bottom), being
+ drawn on the center slice of the
+ scrollbar frame. That way we can
+ make a scrollbar with round-shaped
+ edges so there won't be a free
+ space from the thumb to the frame
+ in top and bottom scrollbar
+ positions. Default is "false".
+ scrollbar_slice The menu frame styled box's slice
+ in which the scrollbar will be
+ drawn. Possible values are
+ "west", "center", "east"
+ (default). "west" - the scrollbar
+ will be drawn in the west slice
+ (right-aligned). "east" - the
+ scrollbar will be drawn in the
+ east slice (left-aligned).
+ "center" - the scrollbar will be
+ drawn in the center slice. Note:
+ in case of "center" slice: a) If
+ the scrollbar should be drawn then
+ boot menu entry's width is
+ decreased by the scrollbar's width
+ and the scrollbar is drawn at the
+ right side of the center slice.
+ b) If the scrollbar won't be drawn
+ then the boot menu entry's width
+ is the width of the center slice.
+ c) We don't necessary need the
+ menu pixmap box to display the
+ scrollbar.
+ scrollbar_left_pad The left scrollbar padding in
+ pixels. Unused if
+ "scrollbar_slice" is "west".
+ scrollbar_right_pad The right scrollbar padding in
+ pixels. Unused if
+ "scrollbar_slice" is "east".
+ scrollbar_top_pad The top scrollbar padding in
+ pixels.
+ scrollbar_bottom_pad The bottom scrollbar padding in
+ pixels.
+ visible Set to "false" to hide the boot
+ menu.
+
+ * canvas Canvas is a container that allows manual placement of
+ components within it. It does not alter the positions of its child
+ components. It assigns all child components their preferred sizes.
+
+ * hbox The *hbox* container lays out its children from left to right,
+ giving each one its preferred width. The height of each child is
+ set to the maximum of the preferred heights of all children.
+
+ * vbox The *vbox* container lays out its children from top to bottom,
+ giving each one its preferred height. The width of each child is
+ set to the maximum of the preferred widths of all children.
+
+7.3.6 Common properties
+-----------------------
+
+The following properties are supported by all components:
+'left'
+ The distance from the left border of container to left border of
+ the object in either of three formats:
+ x Value in pixels
+ p% Percentage
+ p%+x mixture of both
+'top'
+ The distance from the left border of container to left border of
+ the object in same format.
+'width'
+ The width of object in same format.
+'height'
+ The height of object in same format.
+'id'
+ The identifier for the component. This can be any arbitrary
+ string. The ID can be used by scripts to refer to various
+ components in the GUI component tree. Currently, there is one
+ special ID value that GRUB recognizes:
+
+ "__timeout__" Component with this ID will be updated by GRUB
+ and will indicate time elapsed to an automatical
+ boot of the default entry. Affected components:
+ "label", "circular_progress", "progress_bar".
+
+
+File: grub.info, Node: Network, Next: Serial terminal, Prev: Theme file format, Up: Top
+
+8 Booting GRUB from the network
+*******************************
+
+The following instructions don't work for *-emu, i386-qemu,
+i386-coreboot, i386-multiboot, mips_loongson, mips-arc and
+mips_qemu_mips
+
+ To generate a netbootable directory, run:
+
+ grub-mknetdir --net-directory=/srv/tftp --subdir=/boot/grub -d /usr/lib/grub/<platform>
+
+ E.g. for i386-pc:
+
+ grub-mknetdir --net-directory=/srv/tftp --subdir=/boot/grub -d /usr/lib/grub/i386-pc
+
+ Then follow instructions printed out by grub-mknetdir on configuring
+your DHCP server.
+
+ The grub.cfg file is placed in the same directory as the path output
+by grub-mknetdir hereafter referred to as FWPATH. GRUB will search for
+its configuration files in order using the following rules where the
+appended value corresponds to a value on the client machine.
+
+ '(FWPATH)'/grub.cfg-'(UUID OF MACHINE)'
+ '(FWPATH)'/grub.cfg-'(MAC ADDRESS OF NIC)'
+ '(FWPATH)'/grub.cfg-'(IPv4 OR IPv6 ADDRESS)'
+ '(FWPATH)'/grub.cfg
+
+ The UUID is the Client Machine Identifier Option Definition as
+specified in RFC 4578. The client will only attempt to loouk up a UUID
+config file if it was provided by the DHCP server.
+
+ The client will only attempt to look up an IPv6 address config once,
+however, it will try the IPv4 multiple times. The concrete example
+below shows what would happen under the IPv4 case.
+
+ UUID: 7726a678-7fc0-4853-a4f6-c85ac36a120a
+ MAC: 52:54:00:ec:33:81
+ IPV4: 10.0.0.130 (0A000082)
+
+ '(FWPATH)'/grub.cfg-7726a678-7fc0-4853-a4f6-c85ac36a120a
+ '(FWPATH)'/grub.cfg-52-54-00-ec-33-81
+ '(FWPATH)'/grub.cfg-0A000082
+ '(FWPATH)'/grub.cfg-0A00008
+ '(FWPATH)'/grub.cfg-0A0000
+ '(FWPATH)'/grub.cfg-0A000
+ '(FWPATH)'/grub.cfg-0A00
+ '(FWPATH)'/grub.cfg-0A0
+ '(FWPATH)'/grub.cfg-0A
+ '(FWPATH)'/grub.cfg-0
+ '(FWPATH)'/grub.cfg
+
+ This feature is enabled by default but it can be disabled by setting
+the 'feature_net_search_cfg' to 'n'. Since this happens before the
+configuration file is read by GRUB, this option has to be disabled in an
+embedded configuration file (*note Embedded configuration::).
+
+ After GRUB has started, files on the TFTP server will be accessible
+via the '(tftp)' device.
+
+ The server IP address can be controlled by changing the '(tftp)'
+device name to '(tftp,SERVER-IP)'. Note that this should be changed
+both in the prefix and in any references to the device name in the
+configuration file.
+
+ GRUB provides several environment variables which may be used to
+inspect or change the behaviour of the PXE device. In the following
+description <INTERFACE> is placeholder for the name of network interface
+(platform dependent):
+
+'net_<INTERFACE>_ip'
+ The network interface's IP address. Read-only.
+
+'net_<INTERFACE>_mac'
+ The network interface's MAC address. Read-only.
+
+'net_<INTERFACE>_hostname'
+ The client host name provided by DHCP. Read-only.
+
+'net_<INTERFACE>_domain'
+ The client domain name provided by DHCP. Read-only.
+
+'net_<INTERFACE>_rootpath'
+ The path to the client's root disk provided by DHCP. Read-only.
+
+'net_<INTERFACE>_extensionspath'
+ The path to additional DHCP vendor extensions provided by DHCP.
+ Read-only.
+
+'net_<INTERFACE>_boot_file'
+ The boot file name provided by DHCP. Read-only.
+
+'net_<INTERFACE>_dhcp_server_name'
+ The name of the DHCP server responsible for these boot parameters.
+ Read-only.
+
+'net_<INTERFACE>_next_server'
+ The IP address of the next (usually, TFTP) server provided by DHCP.
+ Read-only.
+
+'net_default_interface'
+ Initially set to name of network interface that was used to load
+ grub. Read-write, although setting it affects only interpretation
+ of 'net_default_ip' and 'net_default_mac'
+
+'net_default_ip'
+ The IP address of default interface. Read-only. This is alias for
+ the 'net_${net_default_interface}_ip'.
+
+'net_default_mac'
+ The default interface's MAC address. Read-only. This is alias for
+ the 'net_${net_default_interface}_mac'.
+
+'net_default_server'
+ The default server used by network drives (*note Device syntax::).
+ Read-write, although setting this is only useful before opening a
+ network device.
+
+
+File: grub.info, Node: Serial terminal, Next: Vendor power-on keys, Prev: Network, Up: Top
+
+9 Using GRUB via a serial line
+******************************
+
+This chapter describes how to use the serial terminal support in GRUB.
+
+ If you have many computers or computers with no display/keyboard, it
+could be very useful to control the computers through serial
+communications. To connect one computer with another via a serial line,
+you need to prepare a null-modem (cross) serial cable, and you may need
+to have multiport serial boards, if your computer doesn't have extra
+serial ports. In addition, a terminal emulator is also required, such
+as minicom. Refer to a manual of your operating system, for more
+information.
+
+ As for GRUB, the instruction to set up a serial terminal is quite
+simple. Here is an example:
+
+ grub> serial --unit=0 --speed=9600
+ grub> terminal_input serial; terminal_output serial
+
+ The command 'serial' initializes the serial unit 0 with the speed
+9600bps. The serial unit 0 is usually called 'COM1', so, if you want to
+use COM2, you must specify '--unit=1' instead. This command accepts
+many other options, so please refer to *note serial::, for more details.
+
+ The commands 'terminal_input' (*note terminal_input::) and
+'terminal_output' (*note terminal_output::) choose which type of
+terminal you want to use. In the case above, the terminal will be a
+serial terminal, but you can also pass 'console' to the command, as
+'terminal_input serial console'. In this case, a terminal in which you
+press any key will be selected as a GRUB terminal. In the example
+above, note that you need to put both commands on the same command line,
+as you will lose the ability to type commands on the console after the
+first command.
+
+ However, note that GRUB assumes that your terminal emulator is
+compatible with VT100 by default. This is true for most terminal
+emulators nowadays, but you should pass the option '--dumb' to the
+command if your terminal emulator is not VT100-compatible or implements
+few VT100 escape sequences. If you specify this option then GRUB
+provides you with an alternative menu interface, because the normal menu
+requires several fancy features of your terminal.
+
+
+File: grub.info, Node: Vendor power-on keys, Next: Images, Prev: Serial terminal, Up: Top
+
+10 Using GRUB with vendor power-on keys
+***************************************
+
+Some laptop vendors provide an additional power-on button which boots
+another OS. GRUB supports such buttons with the 'GRUB_TIMEOUT_BUTTON',
+'GRUB_TIMEOUT_STYLE_BUTTON', 'GRUB_DEFAULT_BUTTON', and
+'GRUB_BUTTON_CMOS_ADDRESS' variables in default/grub (*note Simple
+configuration::). 'GRUB_TIMEOUT_BUTTON', 'GRUB_TIMEOUT_STYLE_BUTTON',
+and 'GRUB_DEFAULT_BUTTON' are used instead of the corresponding
+variables without the '_BUTTON' suffix when powered on using the special
+button. 'GRUB_BUTTON_CMOS_ADDRESS' is vendor-specific and partially
+model-specific. Values known to the GRUB team are:
+
+<Dell XPS M1330M>
+ 121:3
+<Dell XPS M1530>
+ 85:3
+<Dell Latitude E4300>
+ 85:3
+<Asus EeePC 1005PE>
+ 84:1 (unconfirmed)
+<LENOVO ThinkPad T410s (2912W1C)>
+ 101:3
+
+ To take full advantage of this function, install GRUB into the MBR
+(*note Installing GRUB using grub-install::).
+
+ If you have a laptop which has a similar feature and not in the above
+list could you figure your address and contribute? To discover the
+address do the following:
+ * boot normally
+ * sudo modprobe nvram
+ sudo cat /dev/nvram | xxd > normal_button.txt
+ * boot using vendor button
+ * sudo modprobe nvram
+ sudo cat /dev/nvram | xxd > normal_vendor.txt
+
+ Then compare these text files and find where a bit was toggled. E.g.
+in case of Dell XPS it was:
+ byte 0x47: 20 --> 28
+ It's a bit number 3 as seen from following table:
+0 01
+1 02
+2 04
+3 08
+4 10
+5 20
+6 40
+7 80
+
+ 0x47 is decimal 71. Linux nvram implementation cuts first 14 bytes
+of CMOS. So the real byte address in CMOS is 71+14=85 So complete
+address is 85:3
+
+
+File: grub.info, Node: Images, Next: Core image size limitation, Prev: Vendor power-on keys, Up: Top
+
+11 GRUB image files
+*******************
+
+GRUB consists of several images: a variety of bootstrap images for
+starting GRUB in various ways, a kernel image, and a set of modules
+which are combined with the kernel image to form a core image. Here is
+a short overview of them.
+
+'boot.img'
+ On PC BIOS systems, this image is the first part of GRUB to start.
+ It is written to a master boot record (MBR) or to the boot sector
+ of a partition. Because a PC boot sector is 512 bytes, the size of
+ this image is exactly 512 bytes.
+
+ The sole function of 'boot.img' is to read the first sector of the
+ core image from a local disk and jump to it. Because of the size
+ restriction, 'boot.img' cannot understand any file system
+ structure, so 'grub-install' hardcodes the location of the first
+ sector of the core image into 'boot.img' when installing GRUB.
+
+'diskboot.img'
+ This image is used as the first sector of the core image when
+ booting from a hard disk. It reads the rest of the core image into
+ memory and starts the kernel. Since file system handling is not
+ yet available, it encodes the location of the core image using a
+ block list format.
+
+'cdboot.img'
+ This image is used as the first sector of the core image when
+ booting from a CD-ROM drive. It performs a similar function to
+ 'diskboot.img'.
+
+'pxeboot.img'
+ This image is used as the start of the core image when booting from
+ the network using PXE. *Note Network::.
+
+'lnxboot.img'
+ This image may be placed at the start of the core image in order to
+ make GRUB look enough like a Linux kernel that it can be booted by
+ LILO using an 'image=' section.
+
+'kernel.img'
+ This image contains GRUB's basic run-time facilities: frameworks
+ for device and file handling, environment variables, the rescue
+ mode command-line parser, and so on. It is rarely used directly,
+ but is built into all core images.
+
+'core.img'
+ This is the core image of GRUB. It is built dynamically from the
+ kernel image and an arbitrary list of modules by the 'grub-mkimage'
+ program. Usually, it contains enough modules to access
+ '/boot/grub', and loads everything else (including menu handling,
+ the ability to load target operating systems, and so on) from the
+ file system at run-time. The modular design allows the core image
+ to be kept small, since the areas of disk where it must be
+ installed are often as small as 32KB.
+
+ *Note BIOS installation::, for details on where the core image can
+ be installed on PC systems.
+
+'*.mod'
+ Everything else in GRUB resides in dynamically loadable modules.
+ These are often loaded automatically, or built into the core image
+ if they are essential, but may also be loaded manually using the
+ 'insmod' command (*note insmod::).
+
+For GRUB Legacy users
+=====================
+
+GRUB 2 has a different design from GRUB Legacy, and so correspondences
+with the images it used cannot be exact. Nevertheless, GRUB Legacy
+users often ask questions in the terms they are familiar with, and so
+here is a brief guide to how GRUB 2's images relate to that.
+
+'stage1'
+ Stage 1 from GRUB Legacy was very similar to 'boot.img' in GRUB 2,
+ and they serve the same function.
+
+'*_stage1_5'
+ In GRUB Legacy, Stage 1.5's function was to include enough
+ filesystem code to allow the much larger Stage 2 to be read from an
+ ordinary filesystem. In this respect, its function was similar to
+ 'core.img' in GRUB 2. However, 'core.img' is much more capable
+ than Stage 1.5 was; since it offers a rescue shell, it is sometimes
+ possible to recover manually in the event that it is unable to load
+ any other modules, for example if partition numbers have changed.
+ 'core.img' is built in a more flexible way, allowing GRUB 2 to
+ support reading modules from advanced disk types such as LVM and
+ RAID.
+
+ GRUB Legacy could run with only Stage 1 and Stage 2 in some limited
+ configurations, while GRUB 2 requires 'core.img' and cannot work
+ without it.
+
+'stage2'
+ GRUB 2 has no single Stage 2 image. Instead, it loads modules from
+ '/boot/grub' at run-time.
+
+'stage2_eltorito'
+ In GRUB 2, images for booting from CD-ROM drives are now
+ constructed using 'cdboot.img' and 'core.img', making sure that the
+ core image contains the 'iso9660' module. It is usually best to
+ use the 'grub-mkrescue' program for this.
+
+'nbgrub'
+ There is as yet no equivalent for 'nbgrub' in GRUB 2; it was used
+ by Etherboot and some other network boot loaders.
+
+'pxegrub'
+ In GRUB 2, images for PXE network booting are now constructed using
+ 'pxeboot.img' and 'core.img', making sure that the core image
+ contains the 'pxe' and 'pxecmd' modules. *Note Network::.
+
+
+File: grub.info, Node: Core image size limitation, Next: Filesystem, Prev: Images, Up: Top
+
+12 Core image size limitation
+*****************************
+
+Heavily limited platforms:
+ * i386-pc (normal and PXE): the core image size (compressed) is
+ limited by 458240 bytes. kernel.img (.text + .data + .bss,
+ uncompressed) is limited by 392704 bytes. module size
+ (uncompressed) + kernel.img (.text + .data, uncompressed) is
+ limited by the size of contiguous chunk at 1M address.
+ * sparc64-ieee1275: kernel.img (.text + .data + .bss) + modules +
+ 256K (stack) + 2M (heap) is limited by space available at 0x4400.
+ On most platforms it's just 3 or 4M since ieee1275 maps only so
+ much.
+ * i386-ieee1275: kernel.img (.text + .data + .bss) + modules is
+ limited by memory available at 0x10000, at most 596K
+
+ Lightly limited platforms:
+
+ * *-xen: limited only by adress space and RAM size.
+ * i386-qemu: kernel.img (.text + .data + .bss) is limited by 392704
+ bytes. (core.img would be limited by ROM size but it's unlimited
+ on qemu
+ * All EFI platforms: limited by contiguous RAM size and possibly
+ firmware bugs
+ * Coreboot and multiboot. kernel.img (.text + .data + .bss) is
+ limited by 392704 bytes. module size is limited by the size of
+ contiguous chunk at 1M address.
+ * mipsel-loongson (ELF), mips(el)-qemu_mips (ELF): if uncompressed:
+ kernel.img (.text + .data) + modules is limited by the space from
+ 80200000 forward if compressed: kernel.img (.text + .data,
+ uncompressed) + modules (uncompressed) + (modules + kernel.img
+ (.text + .data)) (compressed) + decompressor is limited by the
+ space from 80200000 forward
+ * mipsel-loongson (Flash), mips(el)-qemu_mips (Flash): kernel.img
+ (.text + .data) + modules is limited by the space from 80200000
+ forward core.img (final) is limited by flash size (512K on yeeloong
+ and fulooong)
+ * mips-arc: if uncompressed: kernel.img (.text + .data) is limited by
+ the space from 8bd00000 forward modules + dummy decompressor is
+ limited by the space from 8bd00000 backward if compressed:
+ kernel.img (.text + .data, uncompressed) is limited by the space
+ from 8bd00000 forward modules (uncompressed) + (modules +
+ kernel.img (.text + .data)) (compressed, aligned to 1M) + 1M
+ (decompressor + scratch space) is limited by the space from
+ 8bd00000 backward
+ * powerpc-ieee1275: kernel.img (.text + .data + .bss) + modules is
+ limited by space available at 0x200000
+
+
+File: grub.info, Node: Filesystem, Next: Interface, Prev: Core image size limitation, Up: Top
+
+13 Filesystem syntax and semantics
+**********************************
+
+GRUB uses a special syntax for specifying disk drives which can be
+accessed by BIOS. Because of BIOS limitations, GRUB cannot distinguish
+between IDE, ESDI, SCSI, or others. You must know yourself which BIOS
+device is equivalent to which OS device. Normally, that will be clear
+if you see the files in a device or use the command 'search' (*note
+search::).
+
+* Menu:
+
+* Device syntax:: How to specify devices
+* File name syntax:: How to specify files
+* Block list syntax:: How to specify block lists
+
+
+File: grub.info, Node: Device syntax, Next: File name syntax, Up: Filesystem
+
+13.1 How to specify devices
+===========================
+
+The device syntax is like this:
+
+ (DEVICE[,PARTMAP-NAME1PART-NUM1[,PARTMAP-NAME2PART-NUM2[,...]]])
+
+ '[]' means the parameter is optional. DEVICE depends on the disk
+driver in use. BIOS and EFI disks use either 'fd' or 'hd' followed by a
+digit, like 'fd0', or 'cd'. AHCI, PATA (ata), crypto, USB use the name
+of driver followed by a number. Memdisk and host are limited to one
+disk and so it's refered just by driver name. RAID (md), ofdisk
+(ieee1275 and nand), LVM (lvm), LDM, virtio (vdsk) and arcdisk (arc) use
+intrinsic name of disk prefixed by driver name. Additionally just
+"nand" refers to the disk aliased as "nand". Conflicts are solved by
+suffixing a number if necessarry. Commas need to be escaped. Loopback
+uses whatever name specified to 'loopback' command. Hostdisk uses names
+specified in device.map as long as it's of the form [fhc]d[0-9]* or
+hostdisk/<OS DEVICE>. For crypto and RAID (md) additionally you can use
+the syntax <driver name>uuid/<uuid>. For LVM additionally you can use
+the syntax lvmid/<volume-group-uuid>/<volume-uuid>.
+
+ (fd0)
+ (hd0)
+ (cd)
+ (ahci0)
+ (ata0)
+ (crypto0)
+ (usb0)
+ (cryptouuid/123456789abcdef0123456789abcdef0)
+ (mduuid/123456789abcdef0123456789abcdef0)
+ (lvm/system-root)
+ (lvmid/F1ikgD-2RES-306G-il9M-7iwa-4NKW-EbV1NV/eLGuCQ-L4Ka-XUgR-sjtJ-ffch-bajr-fCNfz5)
+ (md/myraid)
+ (md/0)
+ (ieee1275/disk2)
+ (ieee1275//pci@1f\,0/ide@d/disk@2)
+ (nand)
+ (memdisk)
+ (host)
+ (myloop)
+ (hostdisk//dev/sda)
+
+ PART-NUM represents the partition number of DEVICE, starting from
+one. PARTNAME is optional but is recommended since disk may have
+several top-level partmaps. Specifying third and later component you
+can access to subpartitions.
+
+ The syntax '(hd0)' represents using the entire disk (or the MBR when
+installing GRUB), while the syntax '(hd0,1)' represents using the first
+partition of the disk (or the boot sector of the partition when
+installing GRUB).
+
+ (hd0,msdos1)
+ (hd0,msdos1,msdos5)
+ (hd0,msdos1,bsd3)
+ (hd0,netbsd1)
+ (hd0,gpt1)
+ (hd0,1,3)
+
+ If you enabled the network support, the special drives
+'(PROTOCOL[,SERVER])' are also available. Supported protocols are
+'http' and 'tftp'. If SERVER is omitted, value of environment variable
+'net_default_server' is used. Before using the network drive, you must
+initialize the network. *Note Network::, for more information.
+
+ If you boot GRUB from a CD-ROM, '(cd)' is available. *Note Making a
+GRUB bootable CD-ROM::, for details.
+
+
+File: grub.info, Node: File name syntax, Next: Block list syntax, Prev: Device syntax, Up: Filesystem
+
+13.2 How to specify files
+=========================
+
+There are two ways to specify files, by "absolute file name" and by
+"block list".
+
+ An absolute file name resembles a Unix absolute file name, using '/'
+for the directory separator (not '\' as in DOS). One example is
+'(hd0,1)/boot/grub/grub.cfg'. This means the file '/boot/grub/grub.cfg'
+in the first partition of the first hard disk. If you omit the device
+name in an absolute file name, GRUB uses GRUB's "root device"
+implicitly. So if you set the root device to, say, '(hd1,1)' by the
+command 'set root=(hd1,1)' (*note set::), then '/boot/kernel' is the
+same as '(hd1,1)/boot/kernel'.
+
+ On ZFS filesystem the first path component must be
+VOLUME'@'[SNAPSHOT]. So '/rootvol@snap-129/boot/grub/grub.cfg' refers
+to file '/boot/grub/grub.cfg' in snapshot of volume 'rootvol' with name
+'snap-129'. Trailing '@' after volume name is mandatory even if
+snapshot name is omitted.
+
+
+File: grub.info, Node: Block list syntax, Prev: File name syntax, Up: Filesystem
+
+13.3 How to specify block lists
+===============================
+
+A block list is used for specifying a file that doesn't appear in the
+filesystem, like a chainloader. The syntax is
+'[OFFSET]+LENGTH[,[OFFSET]+LENGTH]...'. Here is an example:
+
+ 0+100,200+1,300+300
+
+ This represents that GRUB should read blocks 0 through 99, block 200,
+and blocks 300 through 599. If you omit an offset, then GRUB assumes
+the offset is zero.
+
+ Like the file name syntax (*note File name syntax::), if a blocklist
+does not contain a device name, then GRUB uses GRUB's "root device". So
+'(hd0,2)+1' is the same as '+1' when the root device is '(hd0,2)'.
+
+
+File: grub.info, Node: Interface, Next: Environment, Prev: Filesystem, Up: Top
+
+14 GRUB's user interface
+************************
+
+GRUB has both a simple menu interface for choosing preset entries from a
+configuration file, and a highly flexible command-line for performing
+any desired combination of boot commands.
+
+ GRUB looks for its configuration file as soon as it is loaded. If
+one is found, then the full menu interface is activated using whatever
+entries were found in the file. If you choose the "command-line" menu
+option, or if the configuration file was not found, then GRUB drops to
+the command-line interface.
+
+* Menu:
+
+* Command-line interface:: The flexible command-line interface
+* Menu interface:: The simple menu interface
+* Menu entry editor:: Editing a menu entry
+
+
+File: grub.info, Node: Command-line interface, Next: Menu interface, Up: Interface
+
+14.1 The flexible command-line interface
+========================================
+
+The command-line interface provides a prompt and after it an editable
+text area much like a command-line in Unix or DOS. Each command is
+immediately executed after it is entered(1) (*note Command-line
+interface-Footnote-1::). The commands (*note Command-line and menu
+entry commands::) are a subset of those available in the configuration
+file, used with exactly the same syntax.
+
+ Cursor movement and editing of the text on the line can be done via a
+subset of the functions available in the Bash shell:
+
+<C-f>
+<PC right key>
+ Move forward one character.
+
+<C-b>
+<PC left key>
+ Move back one character.
+
+<C-a>
+<HOME>
+ Move to the start of the line.
+
+<C-e>
+<END>
+ Move the the end of the line.
+
+<C-d>
+<DEL>
+ Delete the character underneath the cursor.
+
+<C-h>
+<BS>
+ Delete the character to the left of the cursor.
+
+<C-k>
+ Kill the text from the current cursor position to the end of the
+ line.
+
+<C-u>
+ Kill backward from the cursor to the beginning of the line.
+
+<C-y>
+ Yank the killed text back into the buffer at the cursor.
+
+<C-p>
+<PC up key>
+ Move up through the history list.
+
+<C-n>
+<PC down key>
+ Move down through the history list.
+
+ When typing commands interactively, if the cursor is within or before
+the first word in the command-line, pressing the <TAB> key (or <C-i>)
+will display a listing of the available commands, and if the cursor is
+after the first word, the '<TAB>' will provide a completion listing of
+disks, partitions, and file names depending on the context. Note that
+to obtain a list of drives, one must open a parenthesis, as 'root ('.
+
+ Note that you cannot use the completion functionality in the TFTP
+filesystem. This is because TFTP doesn't support file name listing for
+the security.
+
+
+File: grub.info, Node: Command-line interface-Footnotes, Up: Command-line interface
+
+ (1) However, this behavior will be changed in the future version, in
+a user-invisible way.
+
+
+File: grub.info, Node: Menu interface, Next: Menu entry editor, Prev: Command-line interface, Up: Interface
+
+14.2 The simple menu interface
+==============================
+
+The menu interface is quite easy to use. Its commands are both
+reasonably intuitive and described on screen.
+
+ Basically, the menu interface provides a list of "boot entries" to
+the user to choose from. Use the arrow keys to select the entry of
+choice, then press <RET> to run it. An optional timeout is available to
+boot the default entry (the first one if not set), which is aborted by
+pressing any key.
+
+ Commands are available to enter a bare command-line by pressing <c>
+(which operates exactly like the non-config-file version of GRUB, but
+allows one to return to the menu if desired by pressing <ESC>) or to
+edit any of the "boot entries" by pressing <e>.
+
+ If you protect the menu interface with a password (*note Security::),
+all you can do is choose an entry by pressing <RET>, or press <p> to
+enter the password.
+
+
+File: grub.info, Node: Menu entry editor, Prev: Menu interface, Up: Interface
+
+14.3 Editing a menu entry
+=========================
+
+The menu entry editor looks much like the main menu interface, but the
+lines in the menu are individual commands in the selected entry instead
+of entry names.
+
+ If an <ESC> is pressed in the editor, it aborts all the changes made
+to the configuration entry and returns to the main menu interface.
+
+ Each line in the menu entry can be edited freely, and you can add new
+lines by pressing <RET> at the end of a line. To boot the edited entry,
+press <Ctrl-x>.
+
+ Although GRUB unfortunately does not support "undo", you can do
+almost the same thing by just returning to the main menu using <ESC>.
+
+
+File: grub.info, Node: Environment, Next: Commands, Prev: Interface, Up: Top
+
+15 GRUB environment variables
+*****************************
+
+GRUB supports environment variables which are rather like those offered
+by all Unix-like systems. Environment variables have a name, which is
+unique and is usually a short identifier, and a value, which is an
+arbitrary string of characters. They may be set (*note set::), unset
+(*note unset::), or looked up (*note Shell-like scripting::) by name.
+
+ A number of environment variables have special meanings to various
+parts of GRUB. Others may be used freely in GRUB configuration files.
+
+* Menu:
+
+* Special environment variables::
+* Environment block::
+
+
+File: grub.info, Node: Special environment variables, Next: Environment block, Up: Environment
+
+15.1 Special environment variables
+==================================
+
+These variables have special meaning to GRUB.
+
+* Menu:
+
+* biosnum::
+* check_signatures::
+* chosen::
+* cmdpath::
+* color_highlight::
+* color_normal::
+* config_directory::
+* config_file::
+* debug::
+* default::
+* fallback::
+* gfxmode::
+* gfxpayload::
+* gfxterm_font::
+* grub_cpu::
+* grub_platform::
+* icondir::
+* lang::
+* locale_dir::
+* menu_color_highlight::
+* menu_color_normal::
+* net_<INTERFACE>_boot_file::
+* net_<INTERFACE>_dhcp_server_name::
+* net_<INTERFACE>_domain::
+* net_<INTERFACE>_extensionspath::
+* net_<INTERFACE>_hostname::
+* net_<INTERFACE>_ip::
+* net_<INTERFACE>_mac::
+* net_<INTERFACE>_next_server::
+* net_<INTERFACE>_rootpath::
+* net_default_interface::
+* net_default_ip::
+* net_default_mac::
+* net_default_server::
+* pager::
+* prefix::
+* pxe_blksize::
+* pxe_default_gateway::
+* pxe_default_server::
+* root::
+* superusers::
+* theme::
+* timeout::
+* timeout_style::
+
+
+File: grub.info, Node: biosnum, Next: check_signatures, Up: Special environment variables
+
+15.1.1 biosnum
+--------------
+
+When chain-loading another boot loader (*note Chain-loading::), GRUB may
+need to know what BIOS drive number corresponds to the root device
+(*note root::) so that it can set up registers properly. If the BIOSNUM
+variable is set, it overrides GRUB's own means of guessing this.
+
+ For an alternative approach which also changes BIOS drive mappings
+for the chain-loaded system, *note drivemap::.
+
+
+File: grub.info, Node: check_signatures, Next: chosen, Prev: biosnum, Up: Special environment variables
+
+15.1.2 check_signatures
+-----------------------
+
+This variable controls whether GRUB enforces digital signature
+validation on loaded files. *Note Using digital signatures::.
+
+
+File: grub.info, Node: chosen, Next: cmdpath, Prev: check_signatures, Up: Special environment variables
+
+15.1.3 chosen
+-------------
+
+When executing a menu entry, GRUB sets the CHOSEN variable to the title
+of the entry being executed.
+
+ If the menu entry is in one or more submenus, then CHOSEN is set to
+the titles of each of the submenus starting from the top level followed
+by the title of the menu entry itself, separated by '>'.
+
+
+File: grub.info, Node: cmdpath, Next: color_highlight, Prev: chosen, Up: Special environment variables
+
+15.1.4 cmdpath
+--------------
+
+The location from which 'core.img' was loaded as an absolute directory
+name (*note File name syntax::). This is set by GRUB at startup based
+on information returned by platform firmware. Not every platform
+provides this information and some may return only device without path
+name.
+
+
+File: grub.info, Node: color_highlight, Next: color_normal, Prev: cmdpath, Up: Special environment variables
+
+15.1.5 color_highlight
+----------------------
+
+This variable contains the "highlight" foreground and background
+terminal colors, separated by a slash ('/'). Setting this variable
+changes those colors. For the available color names, *note
+color_normal::.
+
+ The default is 'black/light-gray'.
+
+
+File: grub.info, Node: color_normal, Next: config_directory, Prev: color_highlight, Up: Special environment variables
+
+15.1.6 color_normal
+-------------------
+
+This variable contains the "normal" foreground and background terminal
+colors, separated by a slash ('/'). Setting this variable changes those
+colors. Each color must be a name from the following list:
+
+ * black
+ * blue
+ * green
+ * cyan
+ * red
+ * magenta
+ * brown
+ * light-gray
+ * dark-gray
+ * light-blue
+ * light-green
+ * light-cyan
+ * light-red
+ * light-magenta
+ * yellow
+ * white
+
+ The default is 'light-gray/black'.
+
+ The color support support varies from terminal to terminal.
+
+ 'morse' has no color support at all.
+
+ 'mda_text' color support is limited to highlighting by black/white
+reversal.
+
+ 'console' on ARC, EMU and IEEE1275, 'serial_*' and 'spkmodem' are
+governed by terminfo and support only 8 colors if in modes 'vt100-color'
+(default for console on emu), 'arc' (default for console on ARC),
+'ieee1275' (default for console on IEEE1275). When in mode 'vt100' then
+the color support is limited to highlighting by black/white reversal.
+When in mode 'dumb' there is no color support.
+
+ When console supports no colors this setting is ignored. When
+console supports 8 colors, then the colors from the second half of the
+previous list are mapped to the matching colors of first half.
+
+ 'console' on EFI and BIOS and 'vga_text' support all 16 colors.
+
+ 'gfxterm' supports all 16 colors and would be theoretically
+extendable to support whole rgb24 palette but currently there is no
+compelling reason to go beyond the current 16 colors.
+
+
+File: grub.info, Node: config_directory, Next: config_file, Prev: color_normal, Up: Special environment variables
+
+15.1.7 config_directory
+-----------------------
+
+This variable is automatically set by GRUB to the directory part of
+current configuration file name (*note config_file::).
+
+
+File: grub.info, Node: config_file, Next: debug, Prev: config_directory, Up: Special environment variables
+
+15.1.8 config_file
+------------------
+
+This variable is automatically set by GRUB to the name of configuration
+file that is being processed by commands 'configfile' (*note
+configfile::) or 'normal' (*note normal::). It is restored to the
+previous value when command completes.
+
+
+File: grub.info, Node: debug, Next: default, Prev: config_file, Up: Special environment variables
+
+15.1.9 debug
+------------
+
+This variable may be set to enable debugging output from various
+components of GRUB. The value is a list of debug facility names
+separated by whitespace or ',', or 'all' to enable all available
+debugging output. The facility names are the first argument to
+grub_dprintf. Consult source for more details.
+
+
+File: grub.info, Node: default, Next: fallback, Prev: debug, Up: Special environment variables
+
+15.1.10 default
+---------------
+
+If this variable is set, it identifies a menu entry that should be
+selected by default, possibly after a timeout (*note timeout::). The
+entry may be identified by number (starting from 0 at each level of the
+hierarchy), by title, or by id.
+
+ For example, if you have:
+
+menuentry 'Example GNU/Linux distribution' --class gnu-linux --id example-gnu-linux {
+ ...
+}
+
+ then you can make this the default using:
+
+ default=example-gnu-linux
+
+ If the entry is in a submenu, then it must be identified using the
+number, title, or id of each of the submenus starting from the top
+level, followed by the number, title, or id of the menu entry itself,
+with each element separated by '>'. For example, take the following
+menu structure:
+
+ GNU/Hurd --id gnu-hurd
+ Standard Boot --id=gnu-hurd-std
+ Rescue shell --id=gnu-hurd-rescue
+ Other platforms --id=other
+ Minix --id=minix
+ Version 3.4.0 --id=minix-3.4.0
+ Version 3.3.0 --id=minix-3.3.0
+ GRUB Invaders --id=grub-invaders
+
+ The more recent release of Minix would then be identified as 'Other
+platforms>Minix>Version 3.4.0', or as '1>0>0', or as
+'other>minix>minix-3.4.0'.
+
+ This variable is often set by 'GRUB_DEFAULT' (*note Simple
+configuration::), 'grub-set-default', or 'grub-reboot'.
+
+
+File: grub.info, Node: fallback, Next: gfxmode, Prev: default, Up: Special environment variables
+
+15.1.11 fallback
+----------------
+
+If this variable is set, it identifies a menu entry that should be
+selected if the default menu entry fails to boot. Entries are
+identified in the same way as for 'default' (*note default::).
+
+
+File: grub.info, Node: gfxmode, Next: gfxpayload, Prev: fallback, Up: Special environment variables
+
+15.1.12 gfxmode
+---------------
+
+If this variable is set, it sets the resolution used on the 'gfxterm'
+graphical terminal. Note that you can only use modes which your
+graphics card supports via VESA BIOS Extensions (VBE), so for example
+native LCD panel resolutions may not be available. The default is
+'auto', which selects a platform-specific default that should look
+reasonable. Supported modes can be listed by 'videoinfo' command in
+GRUB.
+
+ The resolution may be specified as a sequence of one or more modes,
+separated by commas (',') or semicolons (';'); each will be tried in
+turn until one is found. Each mode should be either 'auto',
+'WIDTHxHEIGHT', or 'WIDTHxHEIGHTxDEPTH'.
+
+
+File: grub.info, Node: gfxpayload, Next: gfxterm_font, Prev: gfxmode, Up: Special environment variables
+
+15.1.13 gfxpayload
+------------------
+
+If this variable is set, it controls the video mode in which the Linux
+kernel starts up, replacing the 'vga=' boot option (*note linux::). It
+may be set to 'text' to force the Linux kernel to boot in normal text
+mode, 'keep' to preserve the graphics mode set using 'gfxmode', or any
+of the permitted values for 'gfxmode' to set a particular graphics mode
+(*note gfxmode::).
+
+ Depending on your kernel, your distribution, your graphics card, and
+the phase of the moon, note that using this option may cause GNU/Linux
+to suffer from various display problems, particularly during the early
+part of the boot sequence. If you have problems, set this variable to
+'text' and GRUB will tell Linux to boot in normal text mode.
+
+ The default is platform-specific. On platforms with a native text
+mode (such as PC BIOS platforms), the default is 'text'. Otherwise the
+default may be 'auto' or a specific video mode.
+
+ This variable is often set by 'GRUB_GFXPAYLOAD_LINUX' (*note Simple
+configuration::).
+
+
+File: grub.info, Node: gfxterm_font, Next: grub_cpu, Prev: gfxpayload, Up: Special environment variables
+
+15.1.14 gfxterm_font
+--------------------
+
+If this variable is set, it names a font to use for text on the
+'gfxterm' graphical terminal. Otherwise, 'gfxterm' may use any
+available font.
+
+
+File: grub.info, Node: grub_cpu, Next: grub_platform, Prev: gfxterm_font, Up: Special environment variables
+
+15.1.15 grub_cpu
+----------------
+
+In normal mode (*note normal::), GRUB sets the 'grub_cpu' variable to
+the CPU type for which GRUB was built (e.g. 'i386' or 'powerpc').
+
+
+File: grub.info, Node: grub_platform, Next: icondir, Prev: grub_cpu, Up: Special environment variables
+
+15.1.16 grub_platform
+---------------------
+
+In normal mode (*note normal::), GRUB sets the 'grub_platform' variable
+to the platform for which GRUB was built (e.g. 'pc' or 'efi').
+
+
+File: grub.info, Node: icondir, Next: lang, Prev: grub_platform, Up: Special environment variables
+
+15.1.17 icondir
+---------------
+
+If this variable is set, it names a directory in which the GRUB
+graphical menu should look for icons after looking in the theme's
+'icons' directory. *Note Theme file format::.
+
+
+File: grub.info, Node: lang, Next: locale_dir, Prev: icondir, Up: Special environment variables
+
+15.1.18 lang
+------------
+
+If this variable is set, it names the language code that the 'gettext'
+command (*note gettext::) uses to translate strings. For example,
+French would be named as 'fr', and Simplified Chinese as 'zh_CN'.
+
+ 'grub-mkconfig' (*note Simple configuration::) will try to set a
+reasonable default for this variable based on the system locale.
+
+
+File: grub.info, Node: locale_dir, Next: menu_color_highlight, Prev: lang, Up: Special environment variables
+
+15.1.19 locale_dir
+------------------
+
+If this variable is set, it names the directory where translation files
+may be found (*note gettext::), usually '/boot/grub/locale'. Otherwise,
+internationalization is disabled.
+
+ 'grub-mkconfig' (*note Simple configuration::) will set a reasonable
+default for this variable if internationalization is needed and any
+translation files are available.
+
+
+File: grub.info, Node: menu_color_highlight, Next: menu_color_normal, Prev: locale_dir, Up: Special environment variables
+
+15.1.20 menu_color_highlight
+----------------------------
+
+This variable contains the foreground and background colors to be used
+for the highlighted menu entry, separated by a slash ('/'). Setting
+this variable changes those colors. For the available color names,
+*note color_normal::.
+
+ The default is the value of 'color_highlight' (*note
+color_highlight::).
+
+
+File: grub.info, Node: menu_color_normal, Next: net_<INTERFACE>_boot_file, Prev: menu_color_highlight, Up: Special environment variables
+
+15.1.21 menu_color_normal
+-------------------------
+
+This variable contains the foreground and background colors to be used
+for non-highlighted menu entries, separated by a slash ('/'). Setting
+this variable changes those colors. For the available color names,
+*note color_normal::.
+
+ The default is the value of 'color_normal' (*note color_normal::).
+
+
+File: grub.info, Node: net_<INTERFACE>_boot_file, Next: net_<INTERFACE>_dhcp_server_name, Prev: menu_color_normal, Up: Special environment variables
+
+15.1.22 net_<INTERFACE>_boot_file
+---------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_dhcp_server_name, Next: net_<INTERFACE>_domain, Prev: net_<INTERFACE>_boot_file, Up: Special environment variables
+
+15.1.23 net_<INTERFACE>_dhcp_server_name
+----------------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_domain, Next: net_<INTERFACE>_extensionspath, Prev: net_<INTERFACE>_dhcp_server_name, Up: Special environment variables
+
+15.1.24 net_<INTERFACE>_domain
+------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_extensionspath, Next: net_<INTERFACE>_hostname, Prev: net_<INTERFACE>_domain, Up: Special environment variables
+
+15.1.25 net_<INTERFACE>_extensionspath
+--------------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_hostname, Next: net_<INTERFACE>_ip, Prev: net_<INTERFACE>_extensionspath, Up: Special environment variables
+
+15.1.26 net_<INTERFACE>_hostname
+--------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_ip, Next: net_<INTERFACE>_mac, Prev: net_<INTERFACE>_hostname, Up: Special environment variables
+
+15.1.27 net_<INTERFACE>_ip
+--------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_mac, Next: net_<INTERFACE>_next_server, Prev: net_<INTERFACE>_ip, Up: Special environment variables
+
+15.1.28 net_<INTERFACE>_mac
+---------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_next_server, Next: net_<INTERFACE>_rootpath, Prev: net_<INTERFACE>_mac, Up: Special environment variables
+
+15.1.29 net_<INTERFACE>_next_server
+-----------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_<INTERFACE>_rootpath, Next: net_default_interface, Prev: net_<INTERFACE>_next_server, Up: Special environment variables
+
+15.1.30 net_<INTERFACE>_rootpath
+--------------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_default_interface, Next: net_default_ip, Prev: net_<INTERFACE>_rootpath, Up: Special environment variables
+
+15.1.31 net_default_interface
+-----------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_default_ip, Next: net_default_mac, Prev: net_default_interface, Up: Special environment variables
+
+15.1.32 net_default_ip
+----------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_default_mac, Next: net_default_server, Prev: net_default_ip, Up: Special environment variables
+
+15.1.33 net_default_mac
+-----------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: net_default_server, Next: pager, Prev: net_default_mac, Up: Special environment variables
+
+15.1.34 net_default_server
+--------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: pager, Next: prefix, Prev: net_default_server, Up: Special environment variables
+
+15.1.35 pager
+-------------
+
+If set to '1', pause output after each screenful and wait for keyboard
+input. The default is not to pause output.
+
+
+File: grub.info, Node: prefix, Next: pxe_blksize, Prev: pager, Up: Special environment variables
+
+15.1.36 prefix
+--------------
+
+The location of the '/boot/grub' directory as an absolute file name
+(*note File name syntax::). This is normally set by GRUB at startup
+based on information provided by 'grub-install'. GRUB modules are
+dynamically loaded from this directory, so it must be set correctly in
+order for many parts of GRUB to work.
+
+
+File: grub.info, Node: pxe_blksize, Next: pxe_default_gateway, Prev: prefix, Up: Special environment variables
+
+15.1.37 pxe_blksize
+-------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: pxe_default_gateway, Next: pxe_default_server, Prev: pxe_blksize, Up: Special environment variables
+
+15.1.38 pxe_default_gateway
+---------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: pxe_default_server, Next: root, Prev: pxe_default_gateway, Up: Special environment variables
+
+15.1.39 pxe_default_server
+--------------------------
+
+*Note Network::.
+
+
+File: grub.info, Node: root, Next: superusers, Prev: pxe_default_server, Up: Special environment variables
+
+15.1.40 root
+------------
+
+The root device name (*note Device syntax::). Any file names that do
+not specify an explicit device name are read from this device. The
+default is normally set by GRUB at startup based on the value of
+'prefix' (*note prefix::).
+
+ For example, if GRUB was installed to the first partition of the
+first hard disk, then 'prefix' might be set to '(hd0,msdos1)/boot/grub'
+and 'root' to 'hd0,msdos1'.
+
+
+File: grub.info, Node: superusers, Next: theme, Prev: root, Up: Special environment variables
+
+15.1.41 superusers
+------------------
+
+This variable may be set to a list of superuser names to enable
+authentication support. *Note Security::.
+
+
+File: grub.info, Node: theme, Next: timeout, Prev: superusers, Up: Special environment variables
+
+15.1.42 theme
+-------------
+
+This variable may be set to a directory containing a GRUB graphical menu
+theme. *Note Theme file format::.
+
+ This variable is often set by 'GRUB_THEME' (*note Simple
+configuration::).
+
+
+File: grub.info, Node: timeout, Next: timeout_style, Prev: theme, Up: Special environment variables
+
+15.1.43 timeout
+---------------
+
+If this variable is set, it specifies the time in seconds to wait for
+keyboard input before booting the default menu entry. A timeout of '0'
+means to boot the default entry immediately without displaying the menu;
+a timeout of '-1' (or unset) means to wait indefinitely.
+
+ If 'timeout_style' (*note timeout_style::) is set to 'countdown' or
+'hidden', the timeout is instead counted before the menu is displayed.
+
+ This variable is often set by 'GRUB_TIMEOUT' (*note Simple
+configuration::).
+
+
+File: grub.info, Node: timeout_style, Prev: timeout, Up: Special environment variables
+
+15.1.44 timeout_style
+---------------------
+
+This variable may be set to 'menu', 'countdown', or 'hidden' to control
+the way in which the timeout (*note timeout::) interacts with displaying
+the menu. See the documentation of 'GRUB_TIMEOUT_STYLE' (*note Simple
+configuration::) for details.
+
+
+File: grub.info, Node: Environment block, Prev: Special environment variables, Up: Environment
+
+15.2 The GRUB environment block
+===============================
+
+It is often useful to be able to remember a small amount of information
+from one boot to the next. For example, you might want to set the
+default menu entry based on what was selected the last time. GRUB
+deliberately does not implement support for writing files in order to
+minimise the possibility of the boot loader being responsible for file
+system corruption, so a GRUB configuration file cannot just create a
+file in the ordinary way. However, GRUB provides an "environment block"
+which can be used to save a small amount of state.
+
+ The environment block is a preallocated 1024-byte file, which
+normally lives in '/boot/grub/grubenv' (although you should not assume
+this). At boot time, the 'load_env' command (*note load_env::) loads
+environment variables from it, and the 'save_env' (*note save_env::)
+command saves environment variables to it. From a running system, the
+'grub-editenv' utility can be used to edit the environment block.
+
+ For safety reasons, this storage is only available when installed on
+a plain disk (no LVM or RAID), using a non-checksumming filesystem (no
+ZFS), and using BIOS or EFI functions (no ATA, USB or IEEE1275).
+
+ 'grub-mkconfig' uses this facility to implement 'GRUB_SAVEDEFAULT'
+(*note Simple configuration::).
+
+
+File: grub.info, Node: Commands, Next: Internationalisation, Prev: Environment, Up: Top
+
+16 The list of available commands
+*********************************
+
+In this chapter, we list all commands that are available in GRUB.
+
+ Commands belong to different groups. A few can only be used in the
+global section of the configuration file (or "menu"); most of them can
+be entered on the command-line and can be used either anywhere in the
+menu or specifically in the menu entries.
+
+ In rescue mode, only the 'insmod' (*note insmod::), 'ls' (*note
+ls::), 'set' (*note set::), and 'unset' (*note unset::) commands are
+normally available. If you end up in rescue mode and do not know what
+to do, then *note GRUB only offers a rescue shell::.
+
+* Menu:
+
+* Menu-specific commands::
+* General commands::
+* Command-line and menu entry commands::
+* Networking commands::
+
+
+File: grub.info, Node: Menu-specific commands, Next: General commands, Up: Commands
+
+16.1 The list of commands for the menu only
+===========================================
+
+The semantics used in parsing the configuration file are the following:
+
+ * The files _must_ be in plain-text format.
+
+ * '#' at the beginning of a line in a configuration file means it is
+ only a comment.
+
+ * Options are separated by spaces.
+
+ * All numbers can be either decimal or hexadecimal. A hexadecimal
+ number must be preceded by '0x', and is case-insensitive.
+
+ These commands can only be used in the menu:
+
+* Menu:
+
+* menuentry:: Start a menu entry
+* submenu:: Group menu entries
+
+
+File: grub.info, Node: menuentry, Next: submenu, Up: Menu-specific commands
+
+16.1.1 menuentry
+----------------
+
+ -- Command: menuentry TITLE ['--class=class' ...] ['--users=users']
+ ['--unrestricted'] ['--hotkey=key'] ['--id=id'] [ARG ...] {
+ COMMAND; ... }
+ This defines a GRUB menu entry named TITLE. When this entry is
+ selected from the menu, GRUB will set the CHOSEN environment
+ variable to value of '--id' if '--id' is given, execute the list of
+ commands given within braces, and if the last command in the list
+ returned successfully and a kernel was loaded it will execute the
+ 'boot' command.
+
+ The '--class' option may be used any number of times to group menu
+ entries into classes. Menu themes may display different classes
+ using different styles.
+
+ The '--users' option grants specific users access to specific menu
+ entries. *Note Security::.
+
+ The '--unrestricted' option grants all users access to specific
+ menu entries. *Note Security::.
+
+ The '--hotkey' option associates a hotkey with a menu entry. KEY
+ may be a single letter, or one of the aliases 'backspace', 'tab',
+ or 'delete'.
+
+ The '--id' may be used to associate unique identifier with a menu
+ entry. ID is string of ASCII aphanumeric characters, underscore
+ and hyphen and should not start with a digit.
+
+ All other arguments including TITLE are passed as positional
+ parameters when list of commands is executed with TITLE always
+ assigned to '$1'.
+
+
+File: grub.info, Node: submenu, Prev: menuentry, Up: Menu-specific commands
+
+16.1.2 submenu
+--------------
+
+ -- Command: submenu TITLE ['--class=class' ...] ['--users=users']
+ ['--unrestricted'] ['--hotkey=key'] ['--id=id'] { MENU ENTRIES
+ ... }
+ This defines a submenu. An entry called TITLE will be added to the
+ menu; when that entry is selected, a new menu will be displayed
+ showing all the entries within this submenu.
+
+ All options are the same as in the 'menuentry' command (*note
+ menuentry::).
+
+
+File: grub.info, Node: General commands, Next: Command-line and menu entry commands, Prev: Menu-specific commands, Up: Commands
+
+16.2 The list of general commands
+=================================
+
+Commands usable anywhere in the menu and in the command-line.
+
+* Menu:
+
+* serial:: Set up a serial device
+* terminal_input:: Manage input terminals
+* terminal_output:: Manage output terminals
+* terminfo:: Define terminal type
+
+
+File: grub.info, Node: serial, Next: terminal_input, Up: General commands
+
+16.2.1 serial
+-------------
+
+ -- Command: serial ['--unit=unit'] ['--port=port'] ['--speed=speed']
+ ['--word=word'] ['--parity=parity'] ['--stop=stop']
+ Initialize a serial device. UNIT is a number in the range 0-3
+ specifying which serial port to use; default is 0, which
+ corresponds to the port often called COM1. PORT is the I/O port
+ where the UART is to be found; if specified it takes precedence
+ over UNIT. SPEED is the transmission speed; default is 9600. WORD
+ and STOP are the number of data bits and stop bits. Data bits must
+ be in the range 5-8 and stop bits must be 1 or 2. Default is 8
+ data bits and one stop bit. PARITY is one of 'no', 'odd', 'even'
+ and defaults to 'no'.
+
+ The serial port is not used as a communication channel unless the
+ 'terminal_input' or 'terminal_output' command is used (*note
+ terminal_input::, *note terminal_output::).
+
+ See also *note Serial terminal::.
+
+
+File: grub.info, Node: terminal_input, Next: terminal_output, Prev: serial, Up: General commands
+
+16.2.2 terminal_input
+---------------------
+
+ -- Command: terminal_input ['--append'|'--remove'] [terminal1]
+ [terminal2] ...
+ List or select an input terminal.
+
+ With no arguments, list the active and available input terminals.
+
+ With '--append', add the named terminals to the list of active
+ input terminals; any of these may be used to provide input to GRUB.
+
+ With '--remove', remove the named terminals from the active list.
+
+ With no options but a list of terminal names, make only the listed
+ terminal names active.
+
+
+File: grub.info, Node: terminal_output, Next: terminfo, Prev: terminal_input, Up: General commands
+
+16.2.3 terminal_output
+----------------------
+
+ -- Command: terminal_output ['--append'|'--remove'] [terminal1]
+ [terminal2] ...
+ List or select an output terminal.
+
+ With no arguments, list the active and available output terminals.
+
+ With '--append', add the named terminals to the list of active
+ output terminals; all of these will receive output from GRUB.
+
+ With '--remove', remove the named terminals from the active list.
+
+ With no options but a list of terminal names, make only the listed
+ terminal names active.
+
+
+File: grub.info, Node: terminfo, Prev: terminal_output, Up: General commands
+
+16.2.4 terminfo
+---------------
+
+ -- Command: terminfo ['-a'|'-u'|'-v'] ['-g WxH'] [term] [type]
+ Define the capabilities of your terminal by giving the name of an
+ entry in the terminfo database, which should correspond roughly to
+ a 'TERM' environment variable in Unix.
+
+ The currently available terminal types are 'vt100', 'vt100-color',
+ 'ieee1275', and 'dumb'. If you need other terminal types, please
+ contact us to discuss the best way to include support for these in
+ GRUB.
+
+ The '-a' ('--ascii'), '-u' ('--utf8'), and '-v' ('--visual-utf8')
+ options control how non-ASCII text is displayed. '-a' specifies an
+ ASCII-only terminal; '-u' specifies logically-ordered UTF-8; and
+ '-v' specifies "visually-ordered UTF-8" (in other words, arranged
+ such that a terminal emulator without bidirectional text support
+ will display right-to-left text in the proper order; this is not
+ really proper UTF-8, but a workaround).
+
+ The '-g' ('--geometry') can be used to specify terminal geometry.
+
+ If no option or terminal type is specified, the current terminal
+ type is printed.
+
+
+File: grub.info, Node: Command-line and menu entry commands, Next: Networking commands, Prev: General commands, Up: Commands
+
+16.3 The list of command-line and menu entry commands
+=====================================================
+
+These commands are usable in the command-line and in menu entries. If
+you forget a command, you can run the command 'help' (*note help::).
+
+* Menu:
+
+* [:: Check file types and compare values
+* acpi:: Load ACPI tables
+* authenticate:: Check whether user is in user list
+* background_color:: Set background color for active terminal
+* background_image:: Load background image for active terminal
+* badram:: Filter out bad regions of RAM
+* blocklist:: Print a block list
+* boot:: Start up your operating system
+* cat:: Show the contents of a file
+* chainloader:: Chain-load another boot loader
+* clear:: Clear the screen
+* cmosclean:: Clear bit in CMOS
+* cmosdump:: Dump CMOS contents
+* cmostest:: Test bit in CMOS
+* cmp:: Compare two files
+* configfile:: Load a configuration file
+* cpuid:: Check for CPU features
+* crc:: Compute or check CRC32 checksums
+* cryptomount:: Mount a crypto device
+* cutmem:: Remove memory regions
+* date:: Display or set current date and time
+* devicetree:: Load a device tree blob
+* distrust:: Remove a pubkey from trusted keys
+* drivemap:: Map a drive to another
+* echo:: Display a line of text
+* eval:: Evaluate agruments as GRUB commands
+* export:: Export an environment variable
+* false:: Do nothing, unsuccessfully
+* gettext:: Translate a string
+* gptsync:: Fill an MBR based on GPT entries
+* halt:: Shut down your computer
+* hashsum:: Compute or check hash checksum
+* help:: Show help messages
+* initrd:: Load a Linux initrd
+* initrd16:: Load a Linux initrd (16-bit mode)
+* insmod:: Insert a module
+* keystatus:: Check key modifier status
+* linux:: Load a Linux kernel
+* linux16:: Load a Linux kernel (16-bit mode)
+* list_env:: List variables in environment block
+* list_trusted:: List trusted public keys
+* load_env:: Load variables from environment block
+* loadfont:: Load font files
+* loopback:: Make a device from a filesystem image
+* ls:: List devices or files
+* lsfonts:: List loaded fonts
+* lsmod:: Show loaded modules
+* md5sum:: Compute or check MD5 hash
+* module:: Load module for multiboot kernel
+* multiboot:: Load multiboot compliant kernel
+* nativedisk:: Switch to native disk drivers
+* normal:: Enter normal mode
+* normal_exit:: Exit from normal mode
+* parttool:: Modify partition table entries
+* password:: Set a clear-text password
+* password_pbkdf2:: Set a hashed password
+* play:: Play a tune
+* probe:: Retrieve device info
+* rdmsr:: Read values from model-specific registers
+* read:: Read user input
+* reboot:: Reboot your computer
+* regexp:: Test if regular expression matches string
+* rmmod:: Remove a module
+* save_env:: Save variables to environment block
+* search:: Search devices by file, label, or UUID
+* sendkey:: Emulate keystrokes
+* set:: Set an environment variable
+* sha1sum:: Compute or check SHA1 hash
+* sha256sum:: Compute or check SHA256 hash
+* sha512sum:: Compute or check SHA512 hash
+* sleep:: Wait for a specified number of seconds
+* smbios:: Retrieve SMBIOS information
+* source:: Read a configuration file in same context
+* test:: Check file types and compare values
+* true:: Do nothing, successfully
+* trust:: Add public key to list of trusted keys
+* unset:: Unset an environment variable
+* verify_detached:: Verify detached digital signature
+* videoinfo:: List available video modes
+* wrmsr:: Write values to model-specific registers
+* xen_hypervisor:: Load xen hypervisor binary (only on AArch64)
+* xen_module:: Load xen modules for xen hypervisor (only on AArch64)
+
+
+File: grub.info, Node: [, Next: acpi, Up: Command-line and menu entry commands
+
+16.3.1 [
+--------
+
+ -- Command: '[' expression ']'
+ Alias for 'test EXPRESSION' (*note test::).
+
+
+File: grub.info, Node: acpi, Next: authenticate, Prev: [, Up: Command-line and menu entry commands
+
+16.3.2 acpi
+-----------
+
+ -- Command: acpi ['-1'|'-2']
+ ['--exclude=table1,...'|'--load-only=table1,...']
+ ['--oemid=id'] ['--oemtable=table'] ['--oemtablerev=rev']
+ ['--oemtablecreator=creator'] ['--oemtablecreatorrev=rev']
+ ['--no-ebda'] filename ...
+ Modern BIOS systems normally implement the Advanced Configuration
+ and Power Interface (ACPI), and define various tables that describe
+ the interface between an ACPI-compliant operating system and the
+ firmware. In some cases, the tables provided by default only work
+ well with certain operating systems, and it may be necessary to
+ replace some of them.
+
+ Normally, this command will replace the Root System Description
+ Pointer (RSDP) in the Extended BIOS Data Area to point to the new
+ tables. If the '--no-ebda' option is used, the new tables will be
+ known only to GRUB, but may be used by GRUB's EFI emulation.
+
+ Note: The command is not allowed when lockdown is enforced (*note
+ Lockdown::). Otherwise an attacker can instruct the GRUB to load
+ an SSDT table to overwrite the kernel lockdown configuration and
+ later load and execute unsigned code.
+
+
+File: grub.info, Node: authenticate, Next: background_color, Prev: acpi, Up: Command-line and menu entry commands
+
+16.3.3 authenticate
+-------------------
+
+ -- Command: authenticate [userlist]
+ Check whether user is in USERLIST or listed in the value of
+ variable 'superusers'. See *note superusers:: for valid user list
+ format. If 'superusers' is empty, this command returns true.
+ *Note Security::.
+
+
+File: grub.info, Node: background_color, Next: background_image, Prev: authenticate, Up: Command-line and menu entry commands
+
+16.3.4 background_color
+-----------------------
+
+ -- Command: background_color color
+ Set background color for active terminal. For valid color
+ specifications see *note Colors: Theme file format. Background
+ color can be changed only when using 'gfxterm' for terminal output.
+
+ This command sets color of empty areas without text. Text
+ background color is controlled by environment variables
+ COLOR_NORMAL, COLOR_HIGHLIGHT, MENU_COLOR_NORMAL,
+ MENU_COLOR_HIGHLIGHT. *Note Special environment variables::.
+
+
+File: grub.info, Node: background_image, Next: badram, Prev: background_color, Up: Command-line and menu entry commands
+
+16.3.5 background_image
+-----------------------
+
+ -- Command: background_image [['--mode' 'stretch'|'normal'] file]
+ Load background image for active terminal from FILE. Image is
+ stretched to fill up entire screen unless option '--mode' 'normal'
+ is given. Without arguments remove currently loaded background
+ image. Background image can be changed only when using 'gfxterm'
+ for terminal output.
+
+
+File: grub.info, Node: badram, Next: blocklist, Prev: background_image, Up: Command-line and menu entry commands
+
+16.3.6 badram
+-------------
+
+ -- Command: badram addr,mask[,addr,mask...]
+ Filter out bad RAM.
+
+ This command notifies the memory manager that specified regions of
+ RAM ought to be filtered out (usually, because they're damaged).
+ This remains in effect after a payload kernel has been loaded by
+ GRUB, as long as the loaded kernel obtains its memory map from
+ GRUB. Kernels that support this include Linux, GNU Mach, the kernel
+ of FreeBSD and Multiboot kernels in general.
+
+ Syntax is the same as provided by the Memtest86+ utility
+ (http://www.memtest.org/): a list of address/mask pairs. Given a
+ page-aligned address and a base address / mask pair, if all the
+ bits of the page-aligned address that are enabled by the mask match
+ with the base address, it means this page is to be filtered. This
+ syntax makes it easy to represent patterns that are often result of
+ memory damage, due to physical distribution of memory cells.
+
+ The command is similar to 'cutmem' command.
+
+ Note: The command is not allowed when lockdown is enforced (*note
+ Lockdown::). This prevents removing EFI memory regions to
+ potentially subvert the security mechanisms provided by the UEFI
+ secure boot.
+
+
+File: grub.info, Node: blocklist, Next: boot, Prev: badram, Up: Command-line and menu entry commands
+
+16.3.7 blocklist
+----------------
+
+ -- Command: blocklist file
+ Print a block list (*note Block list syntax::) for FILE.
+
+
+File: grub.info, Node: boot, Next: cat, Prev: blocklist, Up: Command-line and menu entry commands
+
+16.3.8 boot
+-----------
+
+ -- Command: boot
+ Boot the OS or chain-loader which has been loaded. Only necessary
+ if running the fully interactive command-line (it is implicit at
+ the end of a menu entry).
+
+
+File: grub.info, Node: cat, Next: chainloader, Prev: boot, Up: Command-line and menu entry commands
+
+16.3.9 cat
+----------
+
+ -- Command: cat ['--dos'] file
+ Display the contents of the file FILE. This command may be useful
+ to remind you of your OS's root partition:
+
+ grub> cat /etc/fstab
+
+ If the '--dos' option is used, then carriage return / new line
+ pairs will be displayed as a simple new line. Otherwise, the
+ carriage return will be displayed as a control character ('<d>') to
+ make it easier to see when boot problems are caused by a file
+ formatted using DOS-style line endings.
+
+
+File: grub.info, Node: chainloader, Next: clear, Prev: cat, Up: Command-line and menu entry commands
+
+16.3.10 chainloader
+-------------------
+
+ -- Command: chainloader ['--force'] file
+ Load FILE as a chain-loader. Like any other file loaded by the
+ filesystem code, it can use the blocklist notation (*note Block
+ list syntax::) to grab the first sector of the current partition
+ with '+1'. If you specify the option '--force', then load FILE
+ forcibly, whether it has a correct signature or not. This is
+ required when you want to load a defective boot loader, such as SCO
+ UnixWare 7.1.
+
+
+File: grub.info, Node: clear, Next: cmosclean, Prev: chainloader, Up: Command-line and menu entry commands
+
+16.3.11 clear
+-------------
+
+ -- Command: clear
+ Clear the screen.
+
+
+File: grub.info, Node: cmosclean, Next: cmosdump, Prev: clear, Up: Command-line and menu entry commands
+
+16.3.12 cmosclean
+-----------------
+
+ -- Command: cmosclean byte:bit
+ Clear value of bit in CMOS at location BYTE:BIT. This command is
+ available only on platforms that support CMOS.
+
+
+File: grub.info, Node: cmosdump, Next: cmostest, Prev: cmosclean, Up: Command-line and menu entry commands
+
+16.3.13 cmosdump
+----------------
+
+ -- Dump: CMOS contents
+ Dump full CMOS contents as hexadecimal values. This command is
+ available only on platforms that support CMOS.
+
+
+File: grub.info, Node: cmostest, Next: cmp, Prev: cmosdump, Up: Command-line and menu entry commands
+
+16.3.14 cmostest
+----------------
+
+ -- Command: cmostest byte:bit
+ Test value of bit in CMOS at location BYTE:BIT. Exit status is
+ zero if bit is set, non zero otherwise. This command is available
+ only on platforms that support CMOS.
+
+
+File: grub.info, Node: cmp, Next: configfile, Prev: cmostest, Up: Command-line and menu entry commands
+
+16.3.15 cmp
+-----------
+
+ -- Command: cmp file1 file2
+ Compare the file FILE1 with the file FILE2. If they differ in
+ size, print the sizes like this:
+
+ Differ in size: 0x1234 [foo], 0x4321 [bar]
+
+ If the sizes are equal but the bytes at an offset differ, then
+ print the bytes like this:
+
+ Differ at the offset 777: 0xbe [foo], 0xef [bar]
+
+ If they are completely identical, nothing will be printed.
+
+
+File: grub.info, Node: configfile, Next: cpuid, Prev: cmp, Up: Command-line and menu entry commands
+
+16.3.16 configfile
+------------------
+
+ -- Command: configfile file
+ Load FILE as a configuration file. If FILE defines any menu
+ entries, then show a menu containing them immediately. Any
+ environment variable changes made by the commands in FILE will not
+ be preserved after 'configfile' returns.
+
+
+File: grub.info, Node: cpuid, Next: crc, Prev: configfile, Up: Command-line and menu entry commands
+
+16.3.17 cpuid
+-------------
+
+ -- Command: cpuid [-l] [-p]
+ Check for CPU features. This command is only available on x86
+ systems.
+
+ With the '-l' option, return true if the CPU supports long mode
+ (64-bit).
+
+ With the '-p' option, return true if the CPU supports Physical
+ Address Extension (PAE).
+
+ If invoked without options, this command currently behaves as if it
+ had been invoked with '-l'. This may change in the future.
+
+
+File: grub.info, Node: crc, Next: cryptomount, Prev: cpuid, Up: Command-line and menu entry commands
+
+16.3.18 crc
+-----------
+
+ -- Command: crc arg ...
+ Alias for 'hashsum --hash crc32 arg ...'. See command 'hashsum'
+ (*note hashsum::) for full description.
+
+
+File: grub.info, Node: cryptomount, Next: cutmem, Prev: crc, Up: Command-line and menu entry commands
+
+16.3.19 cryptomount
+-------------------
+
+ -- Command: cryptomount device|'-u' uuid|'-a'|'-b'
+ Setup access to encrypted device. If necessary, passphrase is
+ requested interactively. Option DEVICE configures specific grub
+ device (*note Naming convention::); option '-u' UUID configures
+ device with specified UUID; option '-a' configures all detected
+ encrypted devices; option '-b' configures all geli containers that
+ have boot flag set.
+
+ GRUB suports devices encrypted using LUKS, LUKS2 and geli. Note
+ that necessary modules (LUKS, LUKS2 and GELI) have to be loaded
+ manually before this command can be used. For LUKS2 only the
+ PBKDF2 key derivation function is supported, as Argon2 is not yet
+ supported.
+
+ Also, note that, unlike filesystem UUIDs, UUIDs for encrypted
+ devices must be specified without dash separators.
+
+
+File: grub.info, Node: cutmem, Next: date, Prev: cryptomount, Up: Command-line and menu entry commands
+
+16.3.20 cutmem
+--------------
+
+ -- Command: cutmem from[K|M|G] to[K|M|G]
+ Remove any memory regions in specified range.
+
+ This command notifies the memory manager that specified regions of
+ RAM ought to be filtered out. This remains in effect after a
+ payload kernel has been loaded by GRUB, as long as the loaded
+ kernel obtains its memory map from GRUB. Kernels that support this
+ include Linux, GNU Mach, the kernel of FreeBSD and Multiboot
+ kernels in general.
+
+ The command is similar to 'badram' command.
+
+ Note: The command is not allowed when lockdown is enforced (*note
+ Lockdown::). This prevents removing EFI memory regions to
+ potentially subvert the security mechanisms provided by the UEFI
+ secure boot.
+
+
+File: grub.info, Node: date, Next: devicetree, Prev: cutmem, Up: Command-line and menu entry commands
+
+16.3.21 date
+------------
+
+ -- Command: date [[year-]month-day] [hour:minute[:second]]
+ With no arguments, print the current date and time.
+
+ Otherwise, take the current date and time, change any elements
+ specified as arguments, and set the result as the new date and
+ time. For example, 'date 01-01' will set the current month and day
+ to January 1, but leave the year, hour, minute, and second
+ unchanged.
+
+
+File: grub.info, Node: devicetree, Next: distrust, Prev: date, Up: Command-line and menu entry commands
+
+16.3.22 devicetree
+------------------
+
+ -- Command: devicetree file
+ Load a device tree blob (.dtb) from a filesystem, for later use by
+ a Linux kernel. Does not perform merging with any device tree
+ supplied by firmware, but rather replaces it completely.
+
+ Note: The command is not allowed when lockdown is enforced (*note
+ Lockdown::). This is done to prevent subverting various security
+ mechanisms.
+
+
+File: grub.info, Node: distrust, Next: drivemap, Prev: devicetree, Up: Command-line and menu entry commands
+
+16.3.23 distrust
+----------------
+
+ -- Command: distrust pubkey_id
+ Remove public key PUBKEY_ID from GRUB's keyring of trusted keys.
+ PUBKEY_ID is the last four bytes (eight hexadecimal digits) of the
+ GPG v4 key id, which is also the output of 'list_trusted' (*note
+ list_trusted::). Outside of GRUB, the key id can be obtained using
+ 'gpg --fingerprint'). These keys are used to validate signatures
+ when environment variable 'check_signatures' is set to 'enforce'
+ (*note check_signatures::), and by some invocations of
+ 'verify_detached' (*note verify_detached::). *Note Using digital
+ signatures::, for more information.
+
+
+File: grub.info, Node: drivemap, Next: echo, Prev: distrust, Up: Command-line and menu entry commands
+
+16.3.24 drivemap
+----------------
+
+ -- Command: drivemap '-l'|'-r'|['-s'] from_drive to_drive
+ Without options, map the drive FROM_DRIVE to the drive TO_DRIVE.
+ This is necessary when you chain-load some operating systems, such
+ as DOS, if such an OS resides at a non-first drive. For
+ convenience, any partition suffix on the drive is ignored, so you
+ can safely use ${root} as a drive specification.
+
+ With the '-s' option, perform the reverse mapping as well, swapping
+ the two drives.
+
+ With the '-l' option, list the current mappings.
+
+ With the '-r' option, reset all mappings to the default values.
+
+ For example:
+
+ drivemap -s (hd0) (hd1)
+
+
+File: grub.info, Node: echo, Next: eval, Prev: drivemap, Up: Command-line and menu entry commands
+
+16.3.25 echo
+------------
+
+ -- Command: echo ['-n'] ['-e'] string ...
+ Display the requested text and, unless the '-n' option is used, a
+ trailing new line. If there is more than one string, they are
+ separated by spaces in the output. As usual in GRUB commands,
+ variables may be substituted using '${var}'.
+
+ The '-e' option enables interpretation of backslash escapes. The
+ following sequences are recognised:
+
+ '\\'
+ backslash
+
+ '\a'
+ alert (BEL)
+
+ '\c'
+ suppress trailing new line
+
+ '\f'
+ form feed
+
+ '\n'
+ new line
+
+ '\r'
+ carriage return
+
+ '\t'
+ horizontal tab
+
+ '\v'
+ vertical tab
+
+ When interpreting backslash escapes, backslash followed by any
+ other character will print that character.
+
+
+File: grub.info, Node: eval, Next: export, Prev: echo, Up: Command-line and menu entry commands
+
+16.3.26 eval
+------------
+
+ -- Command: eval string ...
+ Concatenate arguments together using single space as separator and
+ evaluate result as sequence of GRUB commands.
+
+
+File: grub.info, Node: export, Next: false, Prev: eval, Up: Command-line and menu entry commands
+
+16.3.27 export
+--------------
+
+ -- Command: export envvar
+ Export the environment variable ENVVAR. Exported variables are
+ visible to subsidiary configuration files loaded using
+ 'configfile'.
+
+
+File: grub.info, Node: false, Next: gettext, Prev: export, Up: Command-line and menu entry commands
+
+16.3.28 false
+-------------
+
+ -- Command: false
+ Do nothing, unsuccessfully. This is mainly useful in control
+ constructs such as 'if' and 'while' (*note Shell-like scripting::).
+
+
+File: grub.info, Node: gettext, Next: gptsync, Prev: false, Up: Command-line and menu entry commands
+
+16.3.29 gettext
+---------------
+
+ -- Command: gettext string
+ Translate STRING into the current language.
+
+ The current language code is stored in the 'lang' variable in
+ GRUB's environment (*note lang::). Translation files in MO format
+ are read from 'locale_dir' (*note locale_dir::), usually
+ '/boot/grub/locale'.
+
+
+File: grub.info, Node: gptsync, Next: halt, Prev: gettext, Up: Command-line and menu entry commands
+
+16.3.30 gptsync
+---------------
+
+ -- Command: gptsync device [partition[+/-[type]]] ...
+ Disks using the GUID Partition Table (GPT) also have a legacy
+ Master Boot Record (MBR) partition table for compatibility with the
+ BIOS and with older operating systems. The legacy MBR can only
+ represent a limited subset of GPT partition entries.
+
+ This command populates the legacy MBR with the specified PARTITION
+ entries on DEVICE. Up to three partitions may be used.
+
+ TYPE is an MBR partition type code; prefix with '0x' if you want to
+ enter this in hexadecimal. The separator between PARTITION and
+ TYPE may be '+' to make the partition active, or '-' to make it
+ inactive; only one partition may be active. If both the separator
+ and type are omitted, then the partition will be inactive.
+
+
+File: grub.info, Node: halt, Next: hashsum, Prev: gptsync, Up: Command-line and menu entry commands
+
+16.3.31 halt
+------------
+
+ -- Command: halt '--no-apm'
+ The command halts the computer. If the '--no-apm' option is
+ specified, no APM BIOS call is performed. Otherwise, the computer
+ is shut down using APM.
+
+
+File: grub.info, Node: hashsum, Next: help, Prev: halt, Up: Command-line and menu entry commands
+
+16.3.32 hashsum
+---------------
+
+ -- Command: hashsum '--hash' hash '--keep-going' '--uncompress'
+ '--check' file ['--prefix' dir]|file ...
+ Compute or verify file hashes. Hash type is selected with option
+ '--hash'. Supported hashes are: 'adler32', 'crc64', 'crc32',
+ 'crc32rfc1510', 'crc24rfc2440', 'md4', 'md5', 'ripemd160', 'sha1',
+ 'sha224', 'sha256', 'sha512', 'sha384', 'tiger192', 'tiger',
+ 'tiger2', 'whirlpool'. Option '--uncompress' uncompresses files
+ before computing hash.
+
+ When list of files is given, hash of each file is computed and
+ printed, followed by file name, each file on a new line.
+
+ When option '--check' is given, it points to a file that contains
+ list of HASH NAME pairs in the same format as used by UNIX 'md5sum'
+ command. Option '--prefix' may be used to give directory where
+ files are located. Hash verification stops after the first
+ mismatch was found unless option '--keep-going' was given. The
+ exit code '$?' is set to 0 if hash verification is successful. If
+ it fails, '$?' is set to a nonzero value.
+
+
+File: grub.info, Node: help, Next: initrd, Prev: hashsum, Up: Command-line and menu entry commands
+
+16.3.33 help
+------------
+
+ -- Command: help [pattern ...]
+ Display helpful information about builtin commands. If you do not
+ specify PATTERN, this command shows short descriptions of all
+ available commands.
+
+ If you specify any PATTERNS, it displays longer information about
+ each of the commands whose names begin with those PATTERNS.
+
+
+File: grub.info, Node: initrd, Next: initrd16, Prev: help, Up: Command-line and menu entry commands
+
+16.3.34 initrd
+--------------
+
+ -- Command: initrd file [file ...]
+ Load, in order, all initial ramdisks for a Linux kernel image, and
+ set the appropriate parameters in the Linux setup area in memory.
+ This may only be used after the 'linux' command (*note linux::) has
+ been run. See also *note GNU/Linux::.
+
+
+File: grub.info, Node: initrd16, Next: insmod, Prev: initrd, Up: Command-line and menu entry commands
+
+16.3.35 initrd16
+----------------
+
+ -- Command: initrd16 file [file ...]
+ Load, in order, all initial ramdisks for a Linux kernel image to be
+ booted in 16-bit mode, and set the appropriate parameters in the
+ Linux setup area in memory. This may only be used after the
+ 'linux16' command (*note linux16::) has been run. See also *note
+ GNU/Linux::.
+
+ This command is only available on x86 systems.
+
+
+File: grub.info, Node: insmod, Next: keystatus, Prev: initrd16, Up: Command-line and menu entry commands
+
+16.3.36 insmod
+--------------
+
+ -- Command: insmod module
+ Insert the dynamic GRUB module called MODULE.
+
+
+File: grub.info, Node: keystatus, Next: linux, Prev: insmod, Up: Command-line and menu entry commands
+
+16.3.37 keystatus
+-----------------
+
+ -- Command: keystatus ['--shift'] ['--ctrl'] ['--alt']
+ Return true if the Shift, Control, or Alt modifier keys are held
+ down, as requested by options. This is useful in scripting, to
+ allow some user control over behaviour without having to wait for a
+ keypress.
+
+ Checking key modifier status is only supported on some platforms.
+ If invoked without any options, the 'keystatus' command returns
+ true if and only if checking key modifier status is supported.
+
+
+File: grub.info, Node: linux, Next: linux16, Prev: keystatus, Up: Command-line and menu entry commands
+
+16.3.38 linux
+-------------
+
+ -- Command: linux file ...
+ Load a Linux kernel image from FILE. The rest of the line is
+ passed verbatim as the "kernel command-line". Any initrd must be
+ reloaded after using this command (*note initrd::).
+
+ On x86 systems, the kernel will be booted using the 32-bit boot
+ protocol. Note that this means that the 'vga=' boot option will
+ not work; if you want to set a special video mode, you will need to
+ use GRUB commands such as 'set gfxpayload=1024x768' or 'set
+ gfxpayload=keep' (to keep the same mode as used in GRUB) instead.
+ GRUB can automatically detect some uses of 'vga=' and translate
+ them to appropriate settings of 'gfxpayload'. The 'linux16'
+ command (*note linux16::) avoids this restriction.
+
+
+File: grub.info, Node: linux16, Next: list_env, Prev: linux, Up: Command-line and menu entry commands
+
+16.3.39 linux16
+---------------
+
+ -- Command: linux16 file ...
+ Load a Linux kernel image from FILE in 16-bit mode. The rest of
+ the line is passed verbatim as the "kernel command-line". Any
+ initrd must be reloaded after using this command (*note
+ initrd16::).
+
+ The kernel will be booted using the traditional 16-bit boot
+ protocol. As well as bypassing problems with 'vga=' described in
+ *note linux::, this permits booting some other programs that
+ implement the Linux boot protocol for the sake of convenience.
+
+ This command is only available on x86 systems.
+
+
+File: grub.info, Node: list_env, Next: list_trusted, Prev: linux16, Up: Command-line and menu entry commands
+
+16.3.40 list_env
+----------------
+
+ -- Command: list_env ['--file' file]
+ List all variables in the environment block file. *Note
+ Environment block::.
+
+ The '--file' option overrides the default location of the
+ environment block.
+
+
+File: grub.info, Node: list_trusted, Next: load_env, Prev: list_env, Up: Command-line and menu entry commands
+
+16.3.41 list_trusted
+--------------------
+
+ -- Command: list_trusted
+ List all public keys trusted by GRUB for validating signatures.
+ The output is in GPG's v4 key fingerprint format (i.e., the output
+ of 'gpg --fingerprint'). The least significant four bytes (last
+ eight hexadecimal digits) can be used as an argument to 'distrust'
+ (*note distrust::). *Note Using digital signatures::, for more
+ information about uses for these keys.
+
+
+File: grub.info, Node: load_env, Next: loadfont, Prev: list_trusted, Up: Command-line and menu entry commands
+
+16.3.42 load_env
+----------------
+
+ -- Command: load_env ['--file' file] ['--skip-sig']
+ [whitelisted_variable_name] ...
+ Load all variables from the environment block file into the
+ environment. *Note Environment block::.
+
+ The '--file' option overrides the default location of the
+ environment block.
+
+ The '--skip-sig' option skips signature checking even when the
+ value of environment variable 'check_signatures' is set to
+ 'enforce' (*note check_signatures::).
+
+ If one or more variable names are provided as arguments, they are
+ interpreted as a whitelist of variables to load from the
+ environment block file. Variables set in the file but not present
+ in the whitelist are ignored.
+
+ The '--skip-sig' option should be used with care, and should always
+ be used in concert with a whitelist of acceptable variables whose
+ values should be set. Failure to employ a carefully constructed
+ whitelist could result in reading a malicious value into critical
+ environment variables from the file, such as setting
+ 'check_signatures=no', modifying 'prefix' to boot from an
+ unexpected location or not at all, etc.
+
+ When used with care, '--skip-sig' and the whitelist enable an
+ administrator to configure a system to boot only signed
+ configurations, but to allow the user to select from among multiple
+ configurations, and to enable "one-shot" boot attempts and
+ "savedefault" behavior. *Note Using digital signatures::, for more
+ information.
+
+
+File: grub.info, Node: loadfont, Next: loopback, Prev: load_env, Up: Command-line and menu entry commands
+
+16.3.43 loadfont
+----------------
+
+ -- Command: loadfont file ...
+ Load specified font files. Unless absolute pathname is given, FILE
+ is assumed to be in directory '$prefix/fonts' with suffix '.pf2'
+ appended. *Note Fonts: Theme file format.
+
+
+File: grub.info, Node: loopback, Next: ls, Prev: loadfont, Up: Command-line and menu entry commands
+
+16.3.44 loopback
+----------------
+
+ -- Command: loopback ['-d'] device file
+ Make the device named DEVICE correspond to the contents of the
+ filesystem image in FILE. For example:
+
+ loopback loop0 /path/to/image
+ ls (loop0)/
+
+ With the '-d' option, delete a device previously created using this
+ command.
+
+
+File: grub.info, Node: ls, Next: lsfonts, Prev: loopback, Up: Command-line and menu entry commands
+
+16.3.45 ls
+----------
+
+ -- Command: ls [arg ...]
+ List devices or files.
+
+ With no arguments, print all devices known to GRUB.
+
+ If the argument is a device name enclosed in parentheses (*note
+ Device syntax::), then print the name of the filesystem of that
+ device.
+
+ If the argument is a directory given as an absolute file name
+ (*note File name syntax::), then list the contents of that
+ directory.
+
+
+File: grub.info, Node: lsfonts, Next: lsmod, Prev: ls, Up: Command-line and menu entry commands
+
+16.3.46 lsfonts
+---------------
+
+ -- Command: lsfonts
+ List loaded fonts.
+
+
+File: grub.info, Node: lsmod, Next: md5sum, Prev: lsfonts, Up: Command-line and menu entry commands
+
+16.3.47 lsmod
+-------------
+
+ -- Command: lsmod
+ Show list of loaded modules.
+
+
+File: grub.info, Node: md5sum, Next: module, Prev: lsmod, Up: Command-line and menu entry commands
+
+16.3.48 md5sum
+--------------
+
+ -- Command: md5sum arg ...
+ Alias for 'hashsum --hash md5 arg ...'. See command 'hashsum'
+ (*note hashsum::) for full description.
+
+
+File: grub.info, Node: module, Next: multiboot, Prev: md5sum, Up: Command-line and menu entry commands
+
+16.3.49 module
+--------------
+
+ -- Command: module [--nounzip] file [arguments]
+ Load a module for multiboot kernel image. The rest of the line is
+ passed verbatim as the module command line.
+
+
+File: grub.info, Node: multiboot, Next: nativedisk, Prev: module, Up: Command-line and menu entry commands
+
+16.3.50 multiboot
+-----------------
+
+ -- Command: multiboot [--quirk-bad-kludge]
+ [--quirk-modules-after-kernel] file ...
+ Load a multiboot kernel image from FILE. The rest of the line is
+ passed verbatim as the "kernel command-line". Any module must be
+ reloaded after using this command (*note module::).
+
+ Some kernels have known problems. You need to specify -quirk-* for
+ those. -quirk-bad-kludge is a problem seen in several products
+ that they include loading kludge information with invalid data in
+ ELF file. GRUB prior to 0.97 and some custom builds preferred ELF
+ information while 0.97 and GRUB 2 use kludge. Use this option to
+ ignore kludge. Known affected systems: old Solaris, SkyOS.
+
+ -quirk-modules-after-kernel is needed for kernels which load at
+ relatively high address e.g. 16MiB mark and can't cope with
+ modules stuffed between 1MiB mark and beginning of the kernel.
+ Known afftected systems: VMWare.
+
+
+File: grub.info, Node: nativedisk, Next: normal, Prev: multiboot, Up: Command-line and menu entry commands
+
+16.3.51 nativedisk
+------------------
+
+ -- Command: nativedisk
+ Switch from firmware disk drivers to native ones. Really useful
+ only on platforms where both firmware and native disk drives are
+ available. Currently i386-pc, i386-efi, i386-ieee1275 and
+ x86_64-efi.
+
+
+File: grub.info, Node: normal, Next: normal_exit, Prev: nativedisk, Up: Command-line and menu entry commands
+
+16.3.52 normal
+--------------
+
+ -- Command: normal [file]
+ Enter normal mode and display the GRUB menu.
+
+ In normal mode, commands, filesystem modules, and cryptography
+ modules are automatically loaded, and the full GRUB script parser
+ is available. Other modules may be explicitly loaded using
+ 'insmod' (*note insmod::).
+
+ If a FILE is given, then commands will be read from that file.
+ Otherwise, they will be read from '$prefix/grub.cfg' if it exists.
+
+ 'normal' may be called from within normal mode, creating a nested
+ environment. It is more usual to use 'configfile' (*note
+ configfile::) for this.
+
+
+File: grub.info, Node: normal_exit, Next: parttool, Prev: normal, Up: Command-line and menu entry commands
+
+16.3.53 normal_exit
+-------------------
+
+ -- Command: normal_exit
+ Exit normal mode (*note normal::). If this instance of normal mode
+ was not nested within another one, then return to rescue mode.
+
+
+File: grub.info, Node: parttool, Next: password, Prev: normal_exit, Up: Command-line and menu entry commands
+
+16.3.54 parttool
+----------------
+
+ -- Command: parttool partition commands
+ Make various modifications to partition table entries.
+
+ Each COMMAND is either a boolean option, in which case it must be
+ followed with '+' or '-' (with no intervening space) to enable or
+ disable that option, or else it takes a value in the form
+ 'COMMAND=VALUE'.
+
+ Currently, 'parttool' is only useful on DOS partition tables (also
+ known as Master Boot Record, or MBR). On these partition tables,
+ the following commands are available:
+
+ 'boot' (boolean)
+ When enabled, this makes the selected partition be the active
+ (bootable) partition on its disk, clearing the active flag on
+ all other partitions. This command is limited to _primary_
+ partitions.
+
+ 'type' (value)
+ Change the type of an existing partition. The value must be a
+ number in the range 0-0xFF (prefix with '0x' to enter it in
+ hexadecimal).
+
+ 'hidden' (boolean)
+ When enabled, this hides the selected partition by setting the
+ "hidden" bit in its partition type code; when disabled,
+ unhides the selected partition by clearing this bit. This is
+ useful only when booting DOS or Windows and multiple primary
+ FAT partitions exist in one disk. See also *note
+ DOS/Windows::.
+
+
+File: grub.info, Node: password, Next: password_pbkdf2, Prev: parttool, Up: Command-line and menu entry commands
+
+16.3.55 password
+----------------
+
+ -- Command: password user clear-password
+ Define a user named USER with password CLEAR-PASSWORD. *Note
+ Security::.
+
+
+File: grub.info, Node: password_pbkdf2, Next: play, Prev: password, Up: Command-line and menu entry commands
+
+16.3.56 password_pbkdf2
+-----------------------
+
+ -- Command: password_pbkdf2 user hashed-password
+ Define a user named USER with password hash HASHED-PASSWORD. Use
+ 'grub-mkpasswd-pbkdf2' (*note Invoking grub-mkpasswd-pbkdf2::) to
+ generate password hashes. *Note Security::.
+
+
+File: grub.info, Node: play, Next: probe, Prev: password_pbkdf2, Up: Command-line and menu entry commands
+
+16.3.57 play
+------------
+
+ -- Command: play file | tempo [pitch1 duration1] [pitch2 duration2] ...
+ Plays a tune
+
+ If the argument is a file name (*note File name syntax::), play the
+ tune recorded in it. The file format is first the tempo as an
+ unsigned 32bit little-endian number, then pairs of unsigned 16bit
+ little-endian numbers for pitch and duration pairs.
+
+ If the arguments are a series of numbers, play the inline tune.
+
+ The tempo is the base for all note durations. 60 gives a 1-second
+ base, 120 gives a half-second base, etc. Pitches are Hz. Set
+ pitch to 0 to produce a rest.
+
+
+File: grub.info, Node: probe, Next: rdmsr, Prev: play, Up: Command-line and menu entry commands
+
+16.3.58 probe
+-------------
+
+ -- Command: probe ['--set' var]
+ '--driver'|'--partmap'|'--fs'|'--fs-uuid'|'--label'|'--part-uuid'
+ device
+ Retrieve device information. If option '--set' is given, assign
+ result to variable VAR, otherwise print information on the screen.
+
+ The option '--part-uuid' is currently only implemented for MSDOS
+ and GPT formatted disks.
+
+
+File: grub.info, Node: rdmsr, Next: read, Prev: probe, Up: Command-line and menu entry commands
+
+16.3.59 rdmsr
+-------------
+
+ -- Command:: rdmsr 0xADDR [-v VARNAME]
+ Read a model-specific register at address 0xADDR. If the parameter
+ '-v' is used and an environment variable VARNAME is given, set that
+ environment variable to the value that was read.
+
+ Please note that on SMP systems, reading from a MSR that has a
+ scope per hardware thread, implies that the value that is returned
+ only applies to the particular cpu/core/thread that runs the
+ command.
+
+ Also, if you specify a reserved or unimplemented MSR address, it
+ will cause a general protection exception (which is not currently
+ being handled) and the system will reboot.
+
+
+File: grub.info, Node: read, Next: reboot, Prev: rdmsr, Up: Command-line and menu entry commands
+
+16.3.60 read
+------------
+
+ -- Command: read [var]
+ Read a line of input from the user. If an environment variable VAR
+ is given, set that environment variable to the line of input that
+ was read, with no terminating newline.
+
+
+File: grub.info, Node: reboot, Next: regexp, Prev: read, Up: Command-line and menu entry commands
+
+16.3.61 reboot
+--------------
+
+ -- Command: reboot
+ Reboot the computer.
+
+
+File: grub.info, Node: regexp, Next: rmmod, Prev: reboot, Up: Command-line and menu entry commands
+
+16.3.62 regexp
+--------------
+
+ -- Command: regexp ['--set' [number:]var] regexp string
+ Test if regular expression REGEXP matches STRING. Supported
+ regular expressions are POSIX.2 Extended Regular Expressions. If
+ option '--set' is given, store NUMBERth matched subexpression in
+ variable VAR. Subexpressions are numbered in order of their
+ opening parentheses starting from '1'. NUMBER defaults to '1'.
+
+
+File: grub.info, Node: rmmod, Next: save_env, Prev: regexp, Up: Command-line and menu entry commands
+
+16.3.63 rmmod
+-------------
+
+ -- Command: rmmod module
+ Remove a loaded MODULE.
+
+
+File: grub.info, Node: save_env, Next: search, Prev: rmmod, Up: Command-line and menu entry commands
+
+16.3.64 save_env
+----------------
+
+ -- Command: save_env ['--file' file] var ...
+ Save the named variables from the environment to the environment
+ block file. *Note Environment block::.
+
+ The '--file' option overrides the default location of the
+ environment block.
+
+ This command will operate successfully even when environment
+ variable 'check_signatures' is set to 'enforce' (*note
+ check_signatures::), since it writes to disk and does not alter the
+ behavior of GRUB based on any contents of disk that have been read.
+ It is possible to modify a digitally signed environment block file
+ from within GRUB using this command, such that its signature will
+ no longer be valid on subsequent boots. Care should be taken in
+ such advanced configurations to avoid rendering the system
+ unbootable. *Note Using digital signatures::, for more
+ information.
+
+
+File: grub.info, Node: search, Next: sendkey, Prev: save_env, Up: Command-line and menu entry commands
+
+16.3.65 search
+--------------
+
+ -- Command: search ['--file'|'--label'|'--fs-uuid'] ['--set' [var]]
+ ['--no-floppy'] name
+ Search devices by file ('-f', '--file'), filesystem label ('-l',
+ '--label'), or filesystem UUID ('-u', '--fs-uuid').
+
+ If the '--set' option is used, the first device found is set as the
+ value of environment variable VAR. The default variable is 'root'.
+
+ The '--no-floppy' option prevents searching floppy devices, which
+ can be slow.
+
+ The 'search.file', 'search.fs_label', and 'search.fs_uuid' commands
+ are aliases for 'search --file', 'search --label', and 'search
+ --fs-uuid' respectively.
+
+
+File: grub.info, Node: sendkey, Next: set, Prev: search, Up: Command-line and menu entry commands
+
+16.3.66 sendkey
+---------------
+
+ -- Command: sendkey
+ ['--num'|'--caps'|'--scroll'|'--insert'|'--pause'|'--left-shift'|'--right-shift'|'--sysrq'|'--numkey'|'--capskey'|'--scrollkey'|'--insertkey'|'--left-alt'|'--right-alt'|'--left-ctrl'|'--right-ctrl'
+ 'on'|'off']... ['no-led'] keystroke
+ Insert keystrokes into the keyboard buffer when booting. Sometimes
+ an operating system or chainloaded boot loader requires particular
+ keys to be pressed: for example, one might need to press a
+ particular key to enter "safe mode", or when chainloading another
+ boot loader one might send keystrokes to it to navigate its menu.
+
+ You may provide up to 16 keystrokes (the length of the BIOS
+ keyboard buffer). Keystroke names may be upper-case or lower-case
+ letters, digits, or taken from the following table:
+
+ Name Key
+ -------------------------------------------------------------------
+ escape Escape
+ exclam !
+ at @
+ numbersign #
+ dollar $
+ percent %
+ caret ^
+ ampersand &
+ asterisk *
+ parenleft (
+ parenright )
+ minus -
+ underscore _
+ equal =
+ plus +
+ backspace Backspace
+ tab Tab
+ bracketleft [
+ braceleft {
+ bracketright ]
+ braceright }
+ enter Enter
+ control press and release Control
+ semicolon ;
+ colon :
+ quote '
+ doublequote "
+ backquote '
+ tilde ~
+ shift press and release left Shift
+ backslash \
+ bar |
+ comma ,
+ less <
+ period .
+ greater >
+ slash /
+ question ?
+ rshift press and release right Shift
+ alt press and release Alt
+ space space bar
+ capslock Caps Lock
+ F1 F1
+ F2 F2
+ F3 F3
+ F4 F4
+ F5 F5
+ F6 F6
+ F7 F7
+ F8 F8
+ F9 F9
+ F10 F10
+ F11 F11
+ F12 F12
+ num1 1 (numeric keypad)
+ num2 2 (numeric keypad)
+ num3 3 (numeric keypad)
+ num4 4 (numeric keypad)
+ num5 5 (numeric keypad)
+ num6 6 (numeric keypad)
+ num7 7 (numeric keypad)
+ num8 8 (numeric keypad)
+ num9 9 (numeric keypad)
+ num0 0 (numeric keypad)
+ numperiod . (numeric keypad)
+ numend End (numeric keypad)
+ numdown Down (numeric keypad)
+ numpgdown Page Down (numeric keypad)
+ numleft Left (numeric keypad)
+ numcenter 5 with Num Lock inactive (numeric
+ keypad)
+ numright Right (numeric keypad)
+ numhome Home (numeric keypad)
+ numup Up (numeric keypad)
+ numpgup Page Up (numeric keypad)
+ numinsert Insert (numeric keypad)
+ numdelete Delete (numeric keypad)
+ numasterisk * (numeric keypad)
+ numminus - (numeric keypad)
+ numplus + (numeric keypad)
+ numslash / (numeric keypad)
+ numenter Enter (numeric keypad)
+ delete Delete
+ insert Insert
+ home Home
+ end End
+ pgdown Page Down
+ pgup Page Up
+ down Down
+ up Up
+ left Left
+ right Right
+
+ As well as keystrokes, the 'sendkey' command takes various options
+ that affect the BIOS keyboard status flags. These options take an
+ 'on' or 'off' parameter, specifying that the corresponding status
+ flag be set or unset; omitting the option for a given status flag
+ will leave that flag at its initial state at boot. The '--num',
+ '--caps', '--scroll', and '--insert' options emulate setting the
+ corresponding mode, while the '--numkey', '--capskey',
+ '--scrollkey', and '--insertkey' options emulate pressing and
+ holding the corresponding key. The other status flag options are
+ self-explanatory.
+
+ If the '--no-led' option is given, the status flag options will
+ have no effect on keyboard LEDs.
+
+ If the 'sendkey' command is given multiple times, then only the
+ last invocation has any effect.
+
+ Since 'sendkey' manipulates the BIOS keyboard buffer, it may cause
+ hangs, reboots, or other misbehaviour on some systems. If the
+ operating system or boot loader that runs after GRUB uses its own
+ keyboard driver rather than the BIOS keyboard functions, then
+ 'sendkey' will have no effect.
+
+ This command is only available on PC BIOS systems.
+
+
+File: grub.info, Node: set, Next: sha1sum, Prev: sendkey, Up: Command-line and menu entry commands
+
+16.3.67 set
+-----------
+
+ -- Command: set [envvar=value]
+ Set the environment variable ENVVAR to VALUE. If invoked with no
+ arguments, print all environment variables with their values.
+
+
+File: grub.info, Node: sha1sum, Next: sha256sum, Prev: set, Up: Command-line and menu entry commands
+
+16.3.68 sha1sum
+---------------
+
+ -- Command: sha1sum arg ...
+ Alias for 'hashsum --hash sha1 arg ...'. See command 'hashsum'
+ (*note hashsum::) for full description.
+
+
+File: grub.info, Node: sha256sum, Next: sha512sum, Prev: sha1sum, Up: Command-line and menu entry commands
+
+16.3.69 sha256sum
+-----------------
+
+ -- Command: sha256sum arg ...
+ Alias for 'hashsum --hash sha256 arg ...'. See command 'hashsum'
+ (*note hashsum::) for full description.
+
+
+File: grub.info, Node: sha512sum, Next: sleep, Prev: sha256sum, Up: Command-line and menu entry commands
+
+16.3.70 sha512sum
+-----------------
+
+ -- Command: sha512sum arg ...
+ Alias for 'hashsum --hash sha512 arg ...'. See command 'hashsum'
+ (*note hashsum::) for full description.
+
+
+File: grub.info, Node: sleep, Next: smbios, Prev: sha512sum, Up: Command-line and menu entry commands
+
+16.3.71 sleep
+-------------
+
+ -- Command: sleep ['--verbose'] ['--interruptible'] count
+ Sleep for COUNT seconds. If option '--interruptible' is given,
+ allow pressing <ESC>, <F4> or holding down <SHIFT> to interrupt
+ sleep. With '--verbose' show countdown of remaining seconds. Exit
+ code is set to 0 if timeout expired and to 1 if timeout was
+ interrupted using any of the mentioned keys.
+
+
+File: grub.info, Node: smbios, Next: source, Prev: sleep, Up: Command-line and menu entry commands
+
+16.3.72 smbios
+--------------
+
+ -- Command: smbios ['--type' TYPE] ['--handle' HANDLE] ['--match'
+ MATCH] ('--get-byte' | '--get-word' | '--get-dword' |
+ '--get-qword' | '--get-string' | '--get-uuid') OFFSET ['--set'
+ VARIABLE]
+ Retrieve SMBIOS information.
+
+ The 'smbios' command returns the value of a field in an SMBIOS
+ structure. The following options determine which structure to
+ select.
+
+ * Specifying '--type' will select structures with a matching
+ TYPE. The type can be any integer from 0 to 255.
+ * Specifying '--handle' will select structures with a matching
+ HANDLE. The handle can be any integer from 0 to 65535.
+ * Specifying '--match' will select structure number MATCH in the
+ filtered list of structures; e.g. 'smbios --type 4 --match 2'
+ will select the second Process Information (Type 4) structure.
+ The list is always ordered the same as the hardware's SMBIOS
+ table. The match number must be a positive integer. If
+ unspecified, the first matching structure will be selected.
+
+ The remaining options determine which field in the selected SMBIOS
+ structure to return. Only one of these options may be specified at
+ a time.
+
+ * When given '--get-byte', return the value of the byte at
+ OFFSET bytes into the selected SMBIOS structure. It will be
+ formatted as an unsigned decimal integer.
+ * When given '--get-word', return the value of the word (two
+ bytes) at OFFSET bytes into the selected SMBIOS structure. It
+ will be formatted as an unsigned decimal integer.
+ * When given '--get-dword', return the value of the dword (four
+ bytes) at OFFSET bytes into the selected SMBIOS structure. It
+ will be formatted as an unsigned decimal integer.
+ * When given '--get-qword', return the value of the qword (eight
+ bytes) at OFFSET bytes into the selected SMBIOS structure. It
+ will be formatted as an unsigned decimal integer.
+ * When given '--get-string', return the string with its index
+ found at OFFSET bytes into the selected SMBIOS structure.
+ * When given '--get-uuid', return the value of the UUID (sixteen
+ bytes) at OFFSET bytes into the selected SMBIOS structure. It
+ will be formatted as lower-case hyphenated hexadecimal digits,
+ with the first three fields as little-endian, and the rest
+ printed byte-by-byte.
+
+ The default action is to print the value of the requested field to
+ the console, but a variable name can be specified with '--set' to
+ store the value instead of printing it.
+
+ For example, this will store and then display the system
+ manufacturer's name.
+
+ smbios --type 1 --get-string 4 --set system_manufacturer
+ echo $system_manufacturer
+
+
+File: grub.info, Node: source, Next: test, Prev: smbios, Up: Command-line and menu entry commands
+
+16.3.73 source
+--------------
+
+ -- Command: source file
+ Read FILE as a configuration file, as if its contents had been
+ incorporated directly into the sourcing file. Unlike 'configfile'
+ (*note configfile::), this executes the contents of FILE without
+ changing context: any environment variable changes made by the
+ commands in FILE will be preserved after 'source' returns, and the
+ menu will not be shown immediately.
+
+
+File: grub.info, Node: test, Next: true, Prev: source, Up: Command-line and menu entry commands
+
+16.3.74 test
+------------
+
+ -- Command: test expression
+ Evaluate EXPRESSION and return zero exit status if result is true,
+ non zero status otherwise.
+
+ EXPRESSION is one of:
+
+ STRING1 '==' STRING2
+ the strings are equal
+ STRING1 '!=' STRING2
+ the strings are not equal
+ STRING1 '<' STRING2
+ STRING1 is lexicographically less than STRING2
+ STRING1 '<=' STRING2
+ STRING1 is lexicographically less or equal than STRING2
+ STRING1 '>' STRING2
+ STRING1 is lexicographically greater than STRING2
+ STRING1 '>=' STRING2
+ STRING1 is lexicographically greater or equal than STRING2
+ INTEGER1 '-eq' INTEGER2
+ INTEGER1 is equal to INTEGER2
+ INTEGER1 '-ge' INTEGER2
+ INTEGER1 is greater than or equal to INTEGER2
+ INTEGER1 '-gt' INTEGER2
+ INTEGER1 is greater than INTEGER2
+ INTEGER1 '-le' INTEGER2
+ INTEGER1 is less than or equal to INTEGER2
+ INTEGER1 '-lt' INTEGER2
+ INTEGER1 is less than INTEGER2
+ INTEGER1 '-ne' INTEGER2
+ INTEGER1 is not equal to INTEGER2
+ PREFIXINTEGER1 '-pgt' PREFIXINTEGER2
+ INTEGER1 is greater than INTEGER2 after stripping off common
+ non-numeric PREFIX.
+ PREFIXINTEGER1 '-plt' PREFIXINTEGER2
+ INTEGER1 is less than INTEGER2 after stripping off common
+ non-numeric PREFIX.
+ FILE1 '-nt' FILE2
+ FILE1 is newer than FILE2 (modification time). Optionally
+ numeric BIAS may be directly appended to '-nt' in which case
+ it is added to the first file modification time.
+ FILE1 '-ot' FILE2
+ FILE1 is older than FILE2 (modification time). Optionally
+ numeric BIAS may be directly appended to '-ot' in which case
+ it is added to the first file modification time.
+ '-d' FILE
+ FILE exists and is a directory
+ '-e' FILE
+ FILE exists
+ '-f' FILE
+ FILE exists and is not a directory
+ '-s' FILE
+ FILE exists and has a size greater than zero
+ '-n' STRING
+ the length of STRING is nonzero
+ STRING
+ STRING is equivalent to '-n STRING'
+ '-z' STRING
+ the length of STRING is zero
+ '(' EXPRESSION ')'
+ EXPRESSION is true
+ '!' EXPRESSION
+ EXPRESSION is false
+ EXPRESSION1 '-a' EXPRESSION2
+ both EXPRESSION1 and EXPRESSION2 are true
+ EXPRESSION1 EXPRESSION2
+ both EXPRESSION1 and EXPRESSION2 are true. This syntax is not
+ POSIX-compliant and is not recommended.
+ EXPRESSION1 '-o' EXPRESSION2
+ either EXPRESSION1 or EXPRESSION2 is true
+
+
+File: grub.info, Node: true, Next: trust, Prev: test, Up: Command-line and menu entry commands
+
+16.3.75 true
+------------
+
+ -- Command: true
+ Do nothing, successfully. This is mainly useful in control
+ constructs such as 'if' and 'while' (*note Shell-like scripting::).
+
+
+File: grub.info, Node: trust, Next: unset, Prev: true, Up: Command-line and menu entry commands
+
+16.3.76 trust
+-------------
+
+ -- Command: trust ['--skip-sig'] pubkey_file
+ Read public key from PUBKEY_FILE and add it to GRUB's internal list
+ of trusted public keys. These keys are used to validate digital
+ signatures when environment variable 'check_signatures' is set to
+ 'enforce'. Note that if 'check_signatures' is set to 'enforce'
+ when 'trust' executes, then PUBKEY_FILE must itself be properly
+ signed. The '--skip-sig' option can be used to disable
+ signature-checking when reading PUBKEY_FILE itself. It is expected
+ that '--skip-sig' is useful for testing and manual booting. *Note
+ Using digital signatures::, for more information.
+
+
+File: grub.info, Node: unset, Next: verify_detached, Prev: trust, Up: Command-line and menu entry commands
+
+16.3.77 unset
+-------------
+
+ -- Command: unset envvar
+ Unset the environment variable ENVVAR.
+
+
+File: grub.info, Node: verify_detached, Next: videoinfo, Prev: unset, Up: Command-line and menu entry commands
+
+16.3.78 verify_detached
+-----------------------
+
+ -- Command: verify_detached ['--skip-sig'] file signature_file
+ [pubkey_file]
+ Verifies a GPG-style detached signature, where the signed file is
+ FILE, and the signature itself is in file SIGNATURE_FILE.
+ Optionally, a specific public key to use can be specified using
+ PUBKEY_FILE. When environment variable 'check_signatures' is set
+ to 'enforce', then PUBKEY_FILE must itself be properly signed by an
+ already-trusted key. An unsigned PUBKEY_FILE can be loaded by
+ specifying '--skip-sig'. If PUBKEY_FILE is omitted, then public
+ keys from GRUB's trusted keys (*note list_trusted::, *note trust::,
+ and *note distrust::) are tried.
+
+ Exit code '$?' is set to 0 if the signature validates successfully.
+ If validation fails, it is set to a non-zero value. *Note Using
+ digital signatures::, for more information.
+
+
+File: grub.info, Node: videoinfo, Next: wrmsr, Prev: verify_detached, Up: Command-line and menu entry commands
+
+16.3.79 videoinfo
+-----------------
+
+ -- Command: videoinfo [[WxH]xD]
+ List available video modes. If resolution is given, show only
+ matching modes.
+
+
+File: grub.info, Node: wrmsr, Next: xen_hypervisor, Prev: videoinfo, Up: Command-line and menu entry commands
+
+16.3.80 wrmsr
+-------------
+
+ -- Command:: wrmsr 0xADDR 0xVALUE
+ Write a 0xVALUE to a model-specific register at address 0xADDR.
+
+ Please note that on SMP systems, writing to a MSR that has a scope
+ per hardware thread, implies that the value that is written only
+ applies to the particular cpu/core/thread that runs the command.
+
+ Also, if you specify a reserved or unimplemented MSR address, it
+ will cause a general protection exception (which is not currently
+ being handled) and the system will reboot.
+
+ Note: The command is not allowed when lockdown is enforced (*note
+ Lockdown::). This is done to prevent subverting various security
+ mechanisms.
+
+
+File: grub.info, Node: xen_hypervisor, Next: xen_module, Prev: wrmsr, Up: Command-line and menu entry commands
+
+16.3.81 xen_hypervisor
+----------------------
+
+ -- Command: xen_hypervisor file [arguments] ...
+ Load a Xen hypervisor binary from FILE. The rest of the line is
+ passed verbatim as the "kernel command-line". Any other binaries
+ must be reloaded after using this command. This command is only
+ available on AArch64 systems.
+
+
+File: grub.info, Node: xen_module, Prev: xen_hypervisor, Up: Command-line and menu entry commands
+
+16.3.82 xen_module
+------------------
+
+ -- Command: xen_module [--nounzip] file [arguments]
+ Load a module for xen hypervisor at the booting process of xen.
+ The rest of the line is passed verbatim as the module command line.
+ Modules should be loaded in the following order: - dom0 kernel
+ image - dom0 ramdisk if present - XSM policy if present This
+ command is only available on AArch64 systems.
+
+
+File: grub.info, Node: Networking commands, Prev: Command-line and menu entry commands, Up: Commands
+
+16.4 The list of networking commands
+====================================
+
+* Menu:
+
+* net_add_addr:: Add a network address
+* net_add_dns:: Add a DNS server
+* net_add_route:: Add routing entry
+* net_bootp:: Perform a bootp/DHCP autoconfiguration
+* net_del_addr:: Remove IP address from interface
+* net_del_dns:: Remove a DNS server
+* net_del_route:: Remove a route entry
+* net_dhcp:: Perform a DHCP autoconfiguration
+* net_get_dhcp_option:: Retrieve DHCP options
+* net_ipv6_autoconf:: Perform IPv6 autoconfiguration
+* net_ls_addr:: List interfaces
+* net_ls_cards:: List network cards
+* net_ls_dns:: List DNS servers
+* net_ls_routes:: List routing entries
+* net_nslookup:: Perform a DNS lookup
+
+
+File: grub.info, Node: net_add_addr, Next: net_add_dns, Up: Networking commands
+
+16.4.1 net_add_addr
+-------------------
+
+ -- Command: net_add_addr INTERFACE CARD ADDRESS
+ Configure additional network INTERFACE with ADDRESS on a network
+ CARD. ADDRESS can be either IP in dotted decimal notation, or
+ symbolic name which is resolved using DNS lookup. If successful,
+ this command also adds local link routing entry to the default
+ subnet of ADDRESS with name INTERFACE':local' via INTERFACE.
+
+
+File: grub.info, Node: net_add_dns, Next: net_add_route, Prev: net_add_addr, Up: Networking commands
+
+16.4.2 net_add_dns
+------------------
+
+ -- Command: net_add_dns SERVER
+ Resolve SERVER IP address and add to the list of DNS servers used
+ during name lookup.
+
+
+File: grub.info, Node: net_add_route, Next: net_bootp, Prev: net_add_dns, Up: Networking commands
+
+16.4.3 net_add_route
+--------------------
+
+ -- Command: net_add_route SHORTNAME IP[/PREFIX] [INTERFACE | 'gw'
+ GATEWAY]
+ Add route to network with address IP as modified by PREFIX via
+ either local INTERFACE or GATEWAY. PREFIX is optional and defaults
+ to 32 for IPv4 address and 128 for IPv6 address. Route is
+ identified by SHORTNAME which can be used to remove it (*note
+ net_del_route::).
+
+
+File: grub.info, Node: net_bootp, Next: net_del_addr, Prev: net_add_route, Up: Networking commands
+
+16.4.4 net_bootp
+----------------
+
+ -- Command: net_bootp [CARD]
+ Alias for net_dhcp, for compatibility with older Grub versions.
+ Will perform the same DHCP handshake with potential fallback to
+ BOOTP as the net_dhcp command (*note net_dhcp::).
+
+
+File: grub.info, Node: net_del_addr, Next: net_del_dns, Prev: net_bootp, Up: Networking commands
+
+16.4.5 net_del_addr
+-------------------
+
+ -- Command: net_del_addr INTERFACE
+ Remove configured INTERFACE with associated address.
+
+
+File: grub.info, Node: net_del_dns, Next: net_del_route, Prev: net_del_addr, Up: Networking commands
+
+16.4.6 net_del_dns
+------------------
+
+ -- Command: net_del_dns ADDRESS
+ Remove ADDRESS from list of servers used during name lookup.
+
+
+File: grub.info, Node: net_del_route, Next: net_dhcp, Prev: net_del_dns, Up: Networking commands
+
+16.4.7 net_del_route
+--------------------
+
+ -- Command: net_del_route SHORTNAME
+ Remove route entry identified by SHORTNAME.
+
+
+File: grub.info, Node: net_dhcp, Next: net_get_dhcp_option, Prev: net_del_route, Up: Networking commands
+
+16.4.8 net_dhcp
+---------------
+
+ -- Command: net_dhcp [CARD]
+ Perform configuration of CARD using DHCP protocol. If no card name
+ is specified, try to configure all existing cards. Falls back to
+ the BOOTP protocol, if needed. If configuration was successful,
+ interface with name CARD':dhcp' and configured address is added to
+ CARD. Additionally the following DHCP options are recognized and
+ processed:
+
+ '1 (Subnet Mask)'
+ Used to calculate network local routing entry for interface
+ CARD':dhcp'.
+ '3 (Router)'
+ Adds default route entry with the name CARD':dhcp:default' via
+ gateway from DHCP option. Note that only option with single
+ route is accepted.
+ '6 (Domain Name Server)'
+ Adds all servers from option value to the list of servers used
+ during name resolution.
+ '12 (Host Name)'
+ Sets environment variable 'net_'<CARD>'_dhcp_hostname' (*note
+ net_<INTERFACE>_hostname::) to the value of option.
+ '15 (Domain Name)'
+ Sets environment variable 'net_'<CARD>'_dhcp_domain' (*note
+ net_<INTERFACE>_domain::) to the value of option.
+ '17 (Root Path)'
+ Sets environment variable 'net_'<CARD>'_dhcp_rootpath' (*note
+ net_<INTERFACE>_rootpath::) to the value of option.
+ '18 (Extensions Path)'
+ Sets environment variable 'net_'<CARD>'_dhcp_extensionspath'
+ (*note net_<INTERFACE>_extensionspath::) to the value of
+ option.
+ '66 (TFTP Server Name)'
+ Sets environment variable 'net_'<CARD>'_dhcp_server_name'
+ (*note net_<INTERFACE>_dhcp_server_name::) to the value of
+ option.
+ '67 (Filename)'
+ Sets environment variable 'net_'<CARD>'_boot_file' (*note
+ net_<INTERFACE>_boot_file::) to the value of option.
+
+
+File: grub.info, Node: net_get_dhcp_option, Next: net_ipv6_autoconf, Prev: net_dhcp, Up: Networking commands
+
+16.4.9 net_get_dhcp_option
+--------------------------
+
+ -- Command: net_get_dhcp_option VAR INTERFACE NUMBER TYPE
+ Request DHCP option NUMBER of TYPE via INTERFACE. TYPE can be one
+ of 'string', 'number' or 'hex'. If option is found, assign its
+ value to variable VAR. Values of types 'number' and 'hex' are
+ converted to string representation.
+
+
+File: grub.info, Node: net_ipv6_autoconf, Next: net_ls_addr, Prev: net_get_dhcp_option, Up: Networking commands
+
+16.4.10 net_ipv6_autoconf
+-------------------------
+
+ -- Command: net_ipv6_autoconf [CARD]
+ Perform IPv6 autoconfiguration by adding to the CARD interface with
+ name CARD':link' and link local MAC-based address. If no card is
+ specified, perform autoconfiguration for all existing cards.
+
+
+File: grub.info, Node: net_ls_addr, Next: net_ls_cards, Prev: net_ipv6_autoconf, Up: Networking commands
+
+16.4.11 net_ls_addr
+-------------------
+
+ -- Command: net_ls_addr
+ List all configured interfaces with their MAC and IP addresses.
+
+
+File: grub.info, Node: net_ls_cards, Next: net_ls_dns, Prev: net_ls_addr, Up: Networking commands
+
+16.4.12 net_ls_cards
+--------------------
+
+ -- Command: net_ls_cards
+ List all detected network cards with their MAC address.
+
+
+File: grub.info, Node: net_ls_dns, Next: net_ls_routes, Prev: net_ls_cards, Up: Networking commands
+
+16.4.13 net_ls_dns
+------------------
+
+ -- Command: net_ls_dns
+ List addresses of DNS servers used during name lookup.
+
+
+File: grub.info, Node: net_ls_routes, Next: net_nslookup, Prev: net_ls_dns, Up: Networking commands
+
+16.4.14 net_ls_routes
+---------------------
+
+ -- Command: net_ls_routes
+ List routing entries.
+
+
+File: grub.info, Node: net_nslookup, Prev: net_ls_routes, Up: Networking commands
+
+16.4.15 net_nslookup
+--------------------
+
+ -- Command: net_nslookup NAME [SERVER]
+ Resolve address of NAME using DNS server SERVER. If no server is
+ given, use default list of servers.
+
+
+File: grub.info, Node: Internationalisation, Next: Security, Prev: Commands, Up: Top
+
+17 Internationalisation
+***********************
+
+17.1 Charset
+============
+
+GRUB uses UTF-8 internally other than in rendering where some
+GRUB-specific appropriate representation is used. All text files
+(including config) are assumed to be encoded in UTF-8.
+
+17.2 Filesystems
+================
+
+NTFS, JFS, UDF, HFS+, exFAT, long filenames in FAT, Joliet part of
+ISO9660 are treated as UTF-16 as per specification. AFS and BFS are
+read as UTF-8, again according to specification. BtrFS, cpio, tar,
+squash4, minix, minix2, minix3, ROMFS, ReiserFS, XFS, ext2, ext3, ext4,
+FAT (short names), F2FS, RockRidge part of ISO9660, nilfs2, UFS1, UFS2
+and ZFS are assumed to be UTF-8. This might be false on systems
+configured with legacy charset but as long as the charset used is
+superset of ASCII you should be able to access ASCII-named files. And
+it's recommended to configure your system to use UTF-8 to access the
+filesystem, convmv may help with migration. ISO9660 (plain) filenames
+are specified as being ASCII or being described with unspecified escape
+sequences. GRUB assumes that the ISO9660 names are UTF-8 (since any
+ASCII is valid UTF-8). There are some old CD-ROMs which use CP437 in
+non-compliant way. You're still able to access files with names
+containing only ASCII characters on such filesystems though. You're
+also able to access any file if the filesystem contains valid Joliet
+(UTF-16) or RockRidge (UTF-8). AFFS, SFS and HFS never use unicode and
+GRUB assumes them to be in Latin1, Latin1 and MacRoman respectively.
+GRUB handles filesystem case-insensitivity however no attempt is
+performed at case conversion of international characters so e.g. a file
+named lowercase greek alpha is treated as different from the one named
+as uppercase alpha. The filesystems in questions are NTFS (except POSIX
+namespace), HFS+ (configurable at mkfs time, default insensitive), SFS
+(configurable at mkfs time, default insensitive), JFS (configurable at
+mkfs time, default sensitive), HFS, AFFS, FAT, exFAT and ZFS
+(configurable on per-subvolume basis by property "casesensitivity",
+default sensitive). On ZFS subvolumes marked as case insensitive files
+containing lowercase international characters are inaccessible. Also
+like all supported filesystems except HFS+ and ZFS (configurable on
+per-subvolume basis by property "normalization", default none) GRUB
+makes no attempt at check of canonical equivalence so a file name
+u-diaresis is treated as distinct from u+combining diaresis. This
+however means that in order to access file on HFS+ its name must be
+specified in normalisation form D. On normalized ZFS subvolumes
+filenames out of normalisation are inaccessible.
+
+17.3 Output terminal
+====================
+
+Firmware output console "console" on ARC and IEEE1275 are limited to
+ASCII.
+
+ BIOS firmware console and VGA text are limited to ASCII and some
+pseudographics.
+
+ None of above mentioned is appropriate for displaying international
+and any unsupported character is replaced with question mark except
+pseudographics which we attempt to approximate with ASCII.
+
+ EFI console on the other hand nominally supports UTF-16 but actual
+language coverage depends on firmware and may be very limited.
+
+ The encoding used on serial can be chosen with 'terminfo' as either
+ASCII, UTF-8 or "visual UTF-8". Last one is against the specification
+but results in correct rendering of right-to-left on some readers which
+don't have own bidi implementation.
+
+ On emu GRUB checks if charset is UTF-8 and uses it if so and uses
+ASCII otherwise.
+
+ When using gfxterm or gfxmenu GRUB itself is responsible for
+rendering the text. In this case GRUB is limited by loaded fonts. If
+fonts contain all required characters then bidirectional text, cursive
+variants and combining marks other than enclosing, half (e.g. left half
+tilde or combining overline) and double ones. Ligatures aren't
+supported though. This should cover European, Middle Eastern (if you
+don't mind lack of lam-alif ligature in Arabic) and East Asian scripts.
+Notable unsupported scripts are Brahmic family and derived as well as
+Mongolian, Tifinagh, Korean Jamo (precomposed characters have no
+problem) and tonal writing (2e5-2e9). GRUB also ignores deprecated (as
+specified in Unicode) characters (e.g. tags). GRUB also doesn't handle
+so called "annotation characters" If you can complete either of two
+lists or, better, propose a patch to improve rendering, please contact
+developer team.
+
+17.4 Input terminal
+===================
+
+Firmware console on BIOS, IEEE1275 and ARC doesn't allow you to enter
+non-ASCII characters. EFI specification allows for such but author is
+unaware of any actual implementations. Serial input is currently
+limited for latin1 (unlikely to change). Own keyboard implementations
+(at_keyboard and usb_keyboard) supports any key but work on
+one-char-per-keystroke. So no dead keys or advanced input method. Also
+there is no keymap change hotkey. In practice it makes difficult to
+enter any text using non-Latin alphabet. Moreover all current input
+consumers are limited to ASCII.
+
+17.5 Gettext
+============
+
+GRUB supports being translated. For this you need to have language *.mo
+files in $prefix/locale, load gettext module and set "lang" variable.
+
+17.6 Regexp
+===========
+
+Regexps work on unicode characters, however no attempt at checking
+cannonical equivalence has been made. Moreover the classes like
+[:alpha:] match only ASCII subset.
+
+17.7 Other
+==========
+
+Currently GRUB always uses YEAR-MONTH-DAY HOUR:MINUTE:SECOND [WEEKDAY]
+24-hour datetime format but weekdays are translated. GRUB always uses
+the decimal number format with [0-9] as digits and . as descimal
+separator and no group separator. IEEE1275 aliases are matched
+case-insensitively except non-ASCII which is matched as binary. Similar
+behaviour is for matching OSBundleRequired. Since IEEE1275 aliases and
+OSBundleRequired don't contain any non-ASCII it should never be a
+problem in practice. Case-sensitive identifiers are matched as raw
+strings, no canonical equivalence check is performed. Case-insenstive
+identifiers are matched as RAW but additionally [a-z] is equivalent to
+[A-Z]. GRUB-defined identifiers use only ASCII and so should
+user-defined ones. Identifiers containing non-ASCII may work but aren't
+supported. Only the ASCII space characters (space U+0020, tab U+000b,
+CR U+000d and LF U+000a) are recognised. Other unicode space characters
+aren't a valid field separator. 'test' (*note test::) tests <, >, <=,
+>=, -pgt and -plt compare the strings in the lexicographical order of
+unicode codepoints, replicating the behaviour of test from coreutils.
+environment variables and commands are listed in the same order.
+
+
+File: grub.info, Node: Security, Next: Platform limitations, Prev: Internationalisation, Up: Top
+
+18 Security
+***********
+
+* Menu:
+
+* Authentication and authorisation:: Users and access control
+* Using digital signatures:: Booting digitally signed code
+* UEFI secure boot and shim:: Booting digitally signed PE files
+* Secure Boot Advanced Targeting:: Embedded information for generation number based revocation
+* Measured Boot:: Measuring boot components
+* Lockdown:: Lockdown when booting on a secure setup
+
+
+File: grub.info, Node: Authentication and authorisation, Next: Using digital signatures, Up: Security
+
+18.1 Authentication and authorisation in GRUB
+=============================================
+
+By default, the boot loader interface is accessible to anyone with
+physical access to the console: anyone can select and edit any menu
+entry, and anyone can get direct access to a GRUB shell prompt. For
+most systems, this is reasonable since anyone with direct physical
+access has a variety of other ways to gain full access, and requiring
+authentication at the boot loader level would only serve to make it
+difficult to recover broken systems.
+
+ However, in some environments, such as kiosks, it may be appropriate
+to lock down the boot loader to require authentication before performing
+certain operations.
+
+ The 'password' (*note password::) and 'password_pbkdf2' (*note
+password_pbkdf2::) commands can be used to define users, each of which
+has an associated password. 'password' sets the password in plain text,
+requiring 'grub.cfg' to be secure; 'password_pbkdf2' sets the password
+hashed using the Password-Based Key Derivation Function (RFC 2898),
+requiring the use of 'grub-mkpasswd-pbkdf2' (*note Invoking
+grub-mkpasswd-pbkdf2::) to generate password hashes.
+
+ In order to enable authentication support, the 'superusers'
+environment variable must be set to a list of usernames, separated by
+any of spaces, commas, semicolons, pipes, or ampersands. Superusers are
+permitted to use the GRUB command line, edit menu entries, and execute
+any menu entry. If 'superusers' is set, then use of the command line
+and editing of menu entries are automatically restricted to superusers.
+Setting 'superusers' to empty string effectively disables both access to
+CLI and editing of menu entries. Note: The environment variable needs
+to be exported to also affect the section defined by the 'submenu'
+command (*note submenu::).
+
+ Other users may be allowed to execute specific menu entries by giving
+a list of usernames (as above) using the '--users' option to the
+'menuentry' command (*note menuentry::). If the '--unrestricted' option
+is used for a menu entry, then that entry is unrestricted. If the
+'--users' option is not used for a menu entry, then that only superusers
+are able to use it.
+
+ Putting this together, a typical 'grub.cfg' fragment might look like
+this:
+
+ set superusers="root"
+ password_pbkdf2 root grub.pbkdf2.sha512.10000.biglongstring
+ password user1 insecure
+
+ menuentry "May be run by any user" --unrestricted {
+ set root=(hd0,1)
+ linux /vmlinuz
+ }
+
+ menuentry "Superusers only" --users "" {
+ set root=(hd0,1)
+ linux /vmlinuz single
+ }
+
+ menuentry "May be run by user1 or a superuser" --users user1 {
+ set root=(hd0,2)
+ chainloader +1
+ }
+
+ The 'grub-mkconfig' program does not yet have built-in support for
+generating configuration files with authentication. You can use
+'/etc/grub.d/40_custom' to add simple superuser authentication, by
+adding 'set superusers=' and 'password' or 'password_pbkdf2' commands.
+
+
+File: grub.info, Node: Using digital signatures, Next: UEFI secure boot and shim, Prev: Authentication and authorisation, Up: Security
+
+18.2 Using digital signatures in GRUB
+=====================================
+
+GRUB's 'core.img' can optionally provide enforcement that all files
+subsequently read from disk are covered by a valid digital signature.
+This document does *not* cover how to ensure that your platform's
+firmware (e.g., Coreboot) validates 'core.img'.
+
+ If environment variable 'check_signatures' (*note check_signatures::)
+is set to 'enforce', then every attempt by the GRUB 'core.img' to load
+another file 'foo' implicitly invokes 'verify_detached foo foo.sig'
+(*note verify_detached::). 'foo.sig' must contain a valid digital
+signature over the contents of 'foo', which can be verified with a
+public key currently trusted by GRUB (*note list_trusted::, *note
+trust::, and *note distrust::). If validation fails, then file 'foo'
+cannot be opened. This failure may halt or otherwise impact the boot
+process.
+
+ An initial trusted public key can be embedded within the GRUB
+'core.img' using the '--pubkey' option to 'grub-install' (*note Invoking
+grub-install::).
+
+ GRUB uses GPG-style detached signatures (meaning that a file
+'foo.sig' will be produced when file 'foo' is signed), and currently
+supports the DSA and RSA signing algorithms. A signing key can be
+generated as follows:
+
+ gpg --gen-key
+
+ An individual file can be signed as follows:
+
+ gpg --detach-sign /path/to/file
+
+ For successful validation of all of GRUB's subcomponents and the
+loaded OS kernel, they must all be signed. One way to accomplish this
+is the following (after having already produced the desired 'grub.cfg'
+file, e.g., by running 'grub-mkconfig' (*note Invoking grub-mkconfig::):
+
+ # Edit /dev/shm/passphrase.txt to contain your signing key's passphrase
+ for i in `find /boot -name "*.cfg" -or -name "*.lst" -or \
+ -name "*.mod" -or -name "vmlinuz*" -or -name "initrd*" -or \
+ -name "grubenv"`;
+ do
+ gpg --batch --detach-sign --passphrase-fd 0 $i < \
+ /dev/shm/passphrase.txt
+ done
+ shred /dev/shm/passphrase.txt
+
+ See also: *note check_signatures::, *note verify_detached::, *note
+trust::, *note list_trusted::, *note distrust::, *note load_env::, *note
+save_env::.
+
+ Note that internally signature enforcement is controlled by setting
+the environment variable 'check_signatures' equal to 'enforce'. Passing
+one or more '--pubkey' options to 'grub-mkimage' implicitly defines
+'check_signatures' equal to 'enforce' in 'core.img' prior to processing
+any configuration files.
+
+ Note that signature checking does *not* prevent an attacker with
+(serial, physical, ...) console access from dropping manually to the
+GRUB console and executing:
+
+ set check_signatures=no
+
+ To prevent this, password-protection (*note Authentication and
+authorisation::) is essential. Note that even with GRUB password
+protection, GRUB itself cannot prevent someone with physical access to
+the machine from altering that machine's firmware (e.g., Coreboot or
+BIOS) configuration to cause the machine to boot from a different
+(attacker-controlled) device. GRUB is at best only one link in a secure
+boot chain.
+
+
+File: grub.info, Node: UEFI secure boot and shim, Next: Secure Boot Advanced Targeting, Prev: Using digital signatures, Up: Security
+
+18.3 UEFI secure boot and shim support
+======================================
+
+The GRUB, except the 'chainloader' command, works with the UEFI secure
+boot and the shim. This functionality is provided by the shim_lock
+verifier. It is built into the 'core.img' and is registered if the UEFI
+secure boot is enabled. The 'shim_lock' variable is set to 'y' when
+shim_lock verifier is registered. If it is desired to use UEFI secure
+boot without shim, one can disable shim_lock by disabling shim
+verification with MokSbState UEFI variable or by building grub image
+with '--disable-shim-lock' option.
+
+ All GRUB modules not stored in the 'core.img', OS kernels, ACPI
+tables, Device Trees, etc. have to be signed, e.g, using PGP.
+Additionally, the commands that can be used to subvert the UEFI secure
+boot mechanism, such as 'iorw' and 'memrw' will not be available when
+the UEFI secure boot is enabled. This is done for security reasons and
+are enforced by the GRUB Lockdown mechanism (*note Lockdown::).
+
+
+File: grub.info, Node: Secure Boot Advanced Targeting, Next: Measured Boot, Prev: UEFI secure boot and shim, Up: Security
+
+18.4 Embedded information for generation number based revocation
+================================================================
+
+The Secure Boot Advanced Targeting (SBAT) is a mechanism to allow the
+revocation of components in the boot path by using generation numbers
+embedded into the EFI binaries. The SBAT metadata is located in an
+.sbat data section that has set of UTF-8 strings as comma-separated
+values (CSV). See <https://github.com/rhboot/shim/blob/main/SBAT.md> for
+more details.
+
+ To add a data section containing the SBAT information into the
+binary, the '--sbat' option of 'grub-mkimage' command should be used.
+The content of a CSV file, encoded with UTF-8, is copied as is to the
+.sbat data section into the generated EFI binary. The CSV file can be
+stored anywhere on the file system.
+
+ grub-mkimage -O x86_64-efi -o grubx64.efi -p '(tftp)/grub' --sbat sbat.csv efinet tftp
+
+
+File: grub.info, Node: Measured Boot, Next: Lockdown, Prev: Secure Boot Advanced Targeting, Up: Security
+
+18.5 Measuring boot components
+==============================
+
+If the tpm module is loaded and the platform has a Trusted Platform
+Module installed, GRUB will log each command executed and each file
+loaded into the TPM event log and extend the PCR values in the TPM
+correspondingly. All events will be logged into the PCR described below
+with a type of EV_IPL and an event description as described below.
+
+Event type PCR Description
+---------------------------------------------------------------------------
+Command 8 All executed commands (including those
+ from configuration files) will be logged
+ and measured as entered with a prefix of
+ "grub_cmd: "
+Kernel command line 8 Any command line passed to a kernel will
+ be logged and measured as entered with a
+ prefix of "kernel_cmdline: "
+Module command line 8 Any command line passed to a kernel
+ module will be logged and measured as
+ entered with a prefix of "module_cmdline:
+ "
+Files 9 Any file read by GRUB will be logged and
+ measured with a descriptive text
+ corresponding to the filename.
+
+ GRUB will not measure its own 'core.img' - it is expected that
+firmware will carry this out. GRUB will also not perform any
+measurements until the tpm module is loaded. As such it is recommended
+that the tpm module be built into 'core.img' in order to avoid a
+potential gap in measurement between 'core.img' being loaded and the tpm
+module being loaded.
+
+ Measured boot is currently only supported on EFI platforms.
+
+
+File: grub.info, Node: Lockdown, Prev: Measured Boot, Up: Security
+
+18.6 Lockdown when booting on a secure setup
+============================================
+
+The GRUB can be locked down when booted on a secure boot environment,
+for example if the UEFI secure boot is enabled. On a locked down
+configuration, the GRUB will be restricted and some operations/commands
+cannot be executed.
+
+ The 'lockdown' variable is set to 'y' when the GRUB is locked down.
+Otherwise it does not exit.
+
+
+File: grub.info, Node: Platform limitations, Next: Platform-specific operations, Prev: Security, Up: Top
+
+19 Platform limitations
+***********************
+
+GRUB2 is designed to be portable and is actually ported across
+platforms. We try to keep all platforms at the level. Unfortunately
+some platforms are better supported than others. This is detailed in
+current and 2 following sections.
+
+ All platforms have an artificially GRUB imposed disk size restriction
+of 1 EiB. In some cases, larger disk sizes can be used, but access will
+not be allowed beyond 1 EiB.
+
+ LUKS2 devices with size larger than 16 EiB are currently not
+supported. They can not be created as crypto devices by cryptomount, so
+can not even be partially read from. LUKS have no limitations other
+than those imposed by the format.
+
+ ARC platform is unable to change datetime (firmware doesn't seem to
+provide a function for it). EMU has similar limitation.
+
+ On EMU platform no serial port is available.
+
+ Console charset refers only to firmware-assisted console. gfxterm is
+always Unicode (see Internationalisation section for its limitations).
+Serial is configurable to UTF-8 or ASCII (see Internationalisation). In
+case of qemu and coreboot ports the refered console is vga_text.
+Loongson always uses gfxterm.
+
+ Most limited one is ASCII. CP437 provides additionally
+pseudographics. GRUB2 doesn't use any language characters from CP437 as
+often CP437 is replaced by national encoding compatible only in
+pseudographics. Unicode is the most versatile charset which supports
+many languages. However the actual console may be much more limited
+depending on firmware
+
+ On BIOS, network is supported only if the image is loaded through
+network. On sparc64, GRUB is unable to determine which server it was
+booted from.
+
+ Direct ATA/AHCI support allows to circumvent various firmware
+limitations but isn't needed for normal operation except on baremetal
+ports.
+
+ AT keyboard support allows keyboard layout remapping and support for
+keys not available through firmware. It isn't needed for normal
+operation except baremetal ports.
+
+ Speaker allows morse and spkmodem communication.
+
+ USB support provides benefits similar to ATA (for USB disks) or AT
+(for USB keyboards). In addition it allows USBserial.
+
+ Chainloading refers to the ability to load another bootloader through
+the same protocol
+
+ Hints allow faster disk discovery by already knowing in advance which
+is the disk in question. On some platforms hints are correct unless you
+move the disk between boots. On other platforms it's just an educated
+guess. Note that hint failure results in just reduced performance, not
+a failure
+
+ BadRAM is the ability to mark some of the RAM as "bad". Note: due to
+protocol limitations mips-loongson (with Linux protocol) and
+mips-qemu_mips can use only memory up to first hole.
+
+ Bootlocation is ability of GRUB to automatically detect where it
+boots from. "disk" means the detection is limited to detecting the disk
+with partition being discovered on install time. "partition" means that
+disk and partiton can be automatically discovered. "file" means that
+boot image file name as well as disk and partition can be discovered.
+For consistency, default install ignores partition and relies solely on
+disk detection. If no bootlocation discovery is available or boot and
+grub-root disks are different, UUID is used instead. On ARC if no
+device to install to is specified, UUID is used instead as well.
+
+ BIOS Coreboot Multiboot Qemu
+video yes yes yes yes
+console CP437 CP437 CP437 CP437
+charset
+network yes (*) no no no
+ATA/AHCI yes yes yes yes
+AT keyboard yes yes yes yes
+Speaker yes yes yes yes
+USB yes yes yes yes
+chainloader local yes yes no
+cpuid partial partial partial partial
+rdmsr partial partial partial partial
+wrmsr partial partial partial partial
+hints guess guess guess guess
+PCI yes yes yes yes
+badram yes yes yes yes
+compression always pointless no no
+exit yes no no no
+bootlocation disk no no no
+
+ ia32 EFI amd64 EFI ia32 Itanium
+ IEEE1275
+video yes yes no no
+console Unicode Unicode ASCII Unicode
+charset
+network yes yes yes yes
+ATA/AHCI yes yes yes no
+AT keyboard yes yes yes no
+Speaker yes yes yes no
+USB yes yes yes no
+chainloader local local no local
+cpuid partial partial partial no
+rdmsr partial partial partial no
+wrmsr partial partial partial no
+hints guess guess good guess
+PCI yes yes yes no
+badram yes yes no yes
+compression no no no no
+exit yes yes yes yes
+bootlocation file file file, file
+ ignored
+
+ Loongson sparc64 Powerpc ARC
+video yes no yes no
+console N/A ASCII ASCII ASCII
+charset
+network no yes (*) yes no
+ATA/AHCI yes no no no
+AT keyboard yes no no no
+Speaker no no no no
+USB yes no no no
+chainloader yes no no no
+cpuid no no no no
+rdmsr no no no no
+wrmsr no no no no
+hints good good good no
+PCI yes no no no
+badram yes (*) no no no
+compression configurable no no configurable
+exit no yes yes yes
+bootlocation no partition file file (*)
+
+ MIPS qemu emu xen
+video no yes no
+console CP437 Unicode (*) ASCII
+charset
+network no yes no
+ATA/AHCI yes no no
+AT keyboard yes no no
+Speaker no no no
+USB N/A yes no
+chainloader yes no yes
+cpuid no no yes
+rdmsr no no yes
+wrmsr no no yes
+hints guess no no
+PCI no no no
+badram yes (*) no no
+compression configurable no no
+exit no yes no
+bootlocation no file no
+
+
+File: grub.info, Node: Platform-specific operations, Next: Supported kernels, Prev: Platform limitations, Up: Top
+
+20 Outline
+**********
+
+Some platforms have features which allows to implement some commands
+useless or not implementable on others.
+
+ Quick summary:
+
+ Information retrieval:
+
+ * mipsel-loongson: lsspd
+ * mips-arc: lsdev
+ * efi: lsefisystab, lssal, lsefimmap, lsefi
+ * i386-pc: lsapm
+ * i386-coreboot: lscoreboot, coreboot_boottime, cbmemc
+ * acpi-enabled (i386-pc, i386-coreboot, i386-multiboot, *-efi):
+ lsacpi
+
+ Workarounds for platform-specific issues:
+ * i386-efi/x86_64-efi: loadbios, fakebios, fix_video
+ * acpi-enabled (i386-pc, i386-coreboot, i386-multiboot, *-efi): acpi
+ (override ACPI tables)
+ * i386-pc: drivemap
+ * i386-pc: sendkey
+
+ Advanced operations for power users:
+ * x86: iorw (direct access to I/O ports)
+
+ Miscelaneous:
+ * cmos (x86-*, ieee1275, mips-qemu_mips, mips-loongson): cmostest
+ (used on some laptops to check for special power-on key), cmosclean
+ * i386-pc: play
+
+
+File: grub.info, Node: Supported kernels, Next: Troubleshooting, Prev: Platform-specific operations, Up: Top
+
+21 Supported boot targets
+*************************
+
+X86 support is summarised in the following table. "Yes" means that the
+kernel works on the given platform, "crashes" means an early kernel
+crash which we hope will be fixed by concerned kernel developers. "no"
+means GRUB doesn't load the given kernel on a given platform.
+"headless" means that the kernel works but lacks console drivers (you
+can still use serial or network console). In case of "no" and "crashes"
+the reason is given in footnote.
+ BIOS Coreboot
+BIOS chainloading yes no (1)
+NTLDR yes no (1)
+Plan9 yes no (1)
+Freedos yes no (1)
+FreeBSD bootloader yes crashes (1)
+32-bit kFreeBSD yes crashes (5)
+64-bit kFreeBSD yes crashes (5)
+32-bit kNetBSD yes crashes (1)
+64-bit kNetBSD yes crashes
+32-bit kOpenBSD yes yes
+64-bit kOpenBSD yes yes
+Multiboot yes yes
+Multiboot2 yes yes
+32-bit Linux (legacy protocol) yes no (1)
+64-bit Linux (legacy protocol) yes no (1)
+32-bit Linux (modern protocol) yes yes
+64-bit Linux (modern protocol) yes yes
+32-bit XNU yes ?
+64-bit XNU yes ?
+32-bit EFI chainloader no (2) no (2)
+64-bit EFI chainloader no (2) no (2)
+Appleloader no (2) no (2)
+
+ Multiboot Qemu
+BIOS chainloading no (1) no (1)
+NTLDR no (1) no (1)
+Plan9 no (1) no (1)
+FreeDOS no (1) no (1)
+FreeBSD bootloader crashes (1) crashes (1)
+32-bit kFreeBSD crashes (5) crashes (5)
+64-bit kFreeBSD crashes (5) crashes (5)
+32-bit kNetBSD crashes (1) crashes (1)
+64-bit kNetBSD yes yes
+32-bit kOpenBSD yes yes
+64-bit kOpenBSD yes yes
+Multiboot yes yes
+Multiboot2 yes yes
+32-bit Linux (legacy protocol) no (1) no (1)
+64-bit Linux (legacy protocol) no (1) no (1)
+32-bit Linux (modern protocol) yes yes
+64-bit Linux (modern protocol) yes yes
+32-bit XNU ? ?
+64-bit XNU ? ?
+32-bit EFI chainloader no (2) no (2)
+64-bit EFI chainloader no (2) no (2)
+Appleloader no (2) no (2)
+
+ ia32 EFI amd64 EFI
+BIOS chainloading no (1) no (1)
+NTLDR no (1) no (1)
+Plan9 no (1) no (1)
+FreeDOS no (1) no (1)
+FreeBSD bootloader crashes (1) crashes (1)
+32-bit kFreeBSD headless headless
+64-bit kFreeBSD headless headless
+32-bit kNetBSD crashes (1) crashes (1)
+64-bit kNetBSD yes yes
+32-bit kOpenBSD headless headless
+64-bit kOpenBSD headless headless
+Multiboot yes yes
+Multiboot2 yes yes
+32-bit Linux (legacy protocol) no (1) no (1)
+64-bit Linux (legacy protocol) no (1) no (1)
+32-bit Linux (modern protocol) yes yes
+64-bit Linux (modern protocol) yes yes
+32-bit XNU yes yes
+64-bit XNU yes (4) yes
+32-bit EFI chainloader yes no (3)
+64-bit EFI chainloader no (3) yes
+Appleloader yes yes
+
+ ia32 IEEE1275
+BIOS chainloading no (1)
+NTLDR no (1)
+Plan9 no (1)
+FreeDOS no (1)
+FreeBSD bootloader crashes (1)
+32-bit kFreeBSD crashes (5)
+64-bit kFreeBSD crashes (5)
+32-bit kNetBSD crashes (1)
+64-bit kNetBSD ?
+32-bit kOpenBSD ?
+64-bit kOpenBSD ?
+Multiboot ?
+Multiboot2 ?
+32-bit Linux (legacy protocol) no (1)
+64-bit Linux (legacy protocol) no (1)
+32-bit Linux (modern protocol) ?
+64-bit Linux (modern protocol) ?
+32-bit XNU ?
+64-bit XNU ?
+32-bit EFI chainloader no (2)
+64-bit EFI chainloader no (2)
+Appleloader no (2)
+
+ 1. Requires BIOS
+ 2. EFI only
+ 3. 32-bit and 64-bit EFI have different structures and work in
+ different CPU modes so it's not possible to chainload 32-bit
+ bootloader on 64-bit platform and vice-versa
+ 4. Some modules may need to be disabled
+ 5. Requires ACPI
+
+ PowerPC, IA64 and Sparc64 ports support only Linux. MIPS port
+supports Linux and multiboot2.
+
+21.1 Boot tests
+===============
+
+As you have seen in previous chapter the support matrix is pretty big
+and some of the configurations are only rarely used. To ensure the
+quality bootchecks are available for all x86 targets except EFI
+chainloader, Appleloader and XNU. All x86 platforms have bootcheck
+facility except ieee1275. Multiboot, multiboot2, BIOS chainloader,
+ntldr and freebsd-bootloader boot targets are tested only with a fake
+kernel images. Only Linux is tested among the payloads using Linux
+protocols.
+
+ Following variables must be defined:
+
+GRUB_PAYLOADS_DIR directory containing the required kernels
+GRUB_CBFSTOOL cbfstool from Coreboot package (for coreboot
+ platform only)
+GRUB_COREBOOT_ROM empty Coreboot ROM
+GRUB_QEMU_OPTS additional options to be supplied to QEMU
+
+ Required files are:
+
+kfreebsd_env.i386 32-bit kFreeBSD device hints
+kfreebsd.i386 32-bit FreeBSD kernel image
+kfreebsd.x86_64, same from 64-bit kFreeBSD
+kfreebsd_env.x86_64
+knetbsd.i386 32-bit NetBSD kernel image
+knetbsd.miniroot.i386 32-bit kNetBSD miniroot.kmod.
+knetbsd.x86_64, same from 64-bit kNetBSD
+knetbsd.miniroot.x86_64
+kopenbsd.i386 32-bit OpenBSD kernel bsd.rd image
+kopenbsd.x86_64 same from 64-bit kOpenBSD
+linux.i386 32-bit Linux
+linux.x86_64 64-bit Linux
+
+
+File: grub.info, Node: Troubleshooting, Next: Invoking grub-install, Prev: Supported kernels, Up: Top
+
+22 Error messages produced by GRUB
+**********************************
+
+* Menu:
+
+* GRUB only offers a rescue shell::
+* Firmware stalls instead of booting GRUB::
+
+
+File: grub.info, Node: GRUB only offers a rescue shell, Next: Firmware stalls instead of booting GRUB, Up: Troubleshooting
+
+22.1 GRUB only offers a rescue shell
+====================================
+
+GRUB's normal start-up procedure involves setting the 'prefix'
+environment variable to a value set in the core image by 'grub-install',
+setting the 'root' variable to match, loading the 'normal' module from
+the prefix, and running the 'normal' command (*note normal::). This
+command is responsible for reading '/boot/grub/grub.cfg', running the
+menu, and doing all the useful things GRUB is supposed to do.
+
+ If, instead, you only get a rescue shell, this usually means that
+GRUB failed to load the 'normal' module for some reason. It may be
+possible to work around this temporarily: for instance, if the reason
+for the failure is that 'prefix' is wrong (perhaps it refers to the
+wrong device, or perhaps the path to '/boot/grub' was not correctly made
+relative to the device), then you can correct this and enter normal mode
+manually:
+
+ # Inspect the current prefix (and other preset variables):
+ set
+ # Find out which devices are available:
+ ls
+ # Set to the correct value, which might be something like this:
+ set prefix=(hd0,1)/grub
+ set root=(hd0,1)
+ insmod normal
+ normal
+
+ However, any problem that leaves you in the rescue shell probably
+means that GRUB was not correctly installed. It may be more useful to
+try to reinstall it properly using 'grub-install DEVICE' (*note Invoking
+grub-install::). When doing this, there are a few things to remember:
+
+ * Drive ordering in your operating system may not be the same as the
+ boot drive ordering used by your firmware. Do not assume that your
+ first hard drive (e.g. '/dev/sda') is the one that your firmware
+ will boot from. 'device.map' (*note Device map::) can be used to
+ override this, but it is usually better to use UUIDs or file system
+ labels and avoid depending on drive ordering entirely.
+
+ * At least on BIOS systems, if you tell 'grub-install' to install
+ GRUB to a partition but GRUB has already been installed in the
+ master boot record, then the GRUB installation in the partition
+ will be ignored.
+
+ * If possible, it is generally best to avoid installing GRUB to a
+ partition (unless it is a special partition for the use of GRUB
+ alone, such as the BIOS Boot Partition used on GPT). Doing this
+ means that GRUB may stop being able to read its core image due to a
+ file system moving blocks around, such as while defragmenting,
+ running checks, or even during normal operation. Installing to the
+ whole disk device is normally more robust.
+
+ * Check that GRUB actually knows how to read from the device and file
+ system containing '/boot/grub'. It will not be able to read from
+ encrypted devices with unsupported encryption scheme, nor from file
+ systems for which support has not yet been added to GRUB.
+
+
+File: grub.info, Node: Firmware stalls instead of booting GRUB, Prev: GRUB only offers a rescue shell, Up: Troubleshooting
+
+22.2 Firmware stalls instead of booting GRUB
+============================================
+
+The EFI implementation of some older MacBook laptops stalls when it gets
+presented a grub-mkrescue ISO image for x86_64-efi target on an USB
+stick. Affected are models of year 2010 or earlier. Workaround is to
+zeroize the bytes 446 to 461 of the EFI partition, where mformat has put
+a partition table entry which claims partition start at block 0. This
+change will not hamper bootability on other machines.
+
+
+File: grub.info, Node: Invoking grub-install, Next: Invoking grub-mkconfig, Prev: Troubleshooting, Up: Top
+
+23 Invoking grub-install
+************************
+
+The program 'grub-install' generates a GRUB core image using
+'grub-mkimage' and installs it on your system. You must specify the
+device name on which you want to install GRUB, like this:
+
+ grub-install INSTALL_DEVICE
+
+ The device name INSTALL_DEVICE is an OS device name or a GRUB device
+name.
+
+ 'grub-install' accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+'--boot-directory=DIR'
+ Install GRUB images under the directory 'DIR/grub/' This option is
+ useful when you want to install GRUB into a separate partition or a
+ removable disk. If this option is not specified then it defaults
+ to '/boot', so
+
+ grub-install /dev/sda
+
+ is equivalent to
+
+ grub-install --boot-directory=/boot/ /dev/sda
+
+ Here is an example in which you have a separate "boot" partition
+ which is mounted on '/mnt/boot':
+
+ grub-install --boot-directory=/mnt/boot /dev/sdb
+
+'--recheck'
+ Recheck the device map, even if '/boot/grub/device.map' already
+ exists. You should use this option whenever you add/remove a disk
+ into/from your computer.
+
+'--no-rs-codes'
+ By default on x86 BIOS systems, 'grub-install' will use some extra
+ space in the bootloader embedding area for Reed-Solomon
+ error-correcting codes. This enables GRUB to still boot
+ successfully if some blocks are corrupted. The exact amount of
+ protection offered is dependent on available space in the embedding
+ area. R sectors of redundancy can tolerate up to R/2 corrupted
+ sectors. This redundancy may be cumbersome if attempting to
+ cryptographically validate the contents of the bootloader embedding
+ area, or in more modern systems with GPT-style partition tables
+ (*note BIOS installation::) where GRUB does not reside in any
+ unpartitioned space outside of the MBR. Disable the Reed-Solomon
+ codes with this option.
+
+
+File: grub.info, Node: Invoking grub-mkconfig, Next: Invoking grub-mkpasswd-pbkdf2, Prev: Invoking grub-install, Up: Top
+
+24 Invoking grub-mkconfig
+*************************
+
+The program 'grub-mkconfig' generates a configuration file for GRUB
+(*note Simple configuration::).
+
+ grub-mkconfig -o /boot/grub/grub.cfg
+
+ 'grub-mkconfig' accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+'-o FILE'
+'--output=FILE'
+ Send the generated configuration file to FILE. The default is to
+ send it to standard output.
+
+
+File: grub.info, Node: Invoking grub-mkpasswd-pbkdf2, Next: Invoking grub-mkrelpath, Prev: Invoking grub-mkconfig, Up: Top
+
+25 Invoking grub-mkpasswd-pbkdf2
+********************************
+
+The program 'grub-mkpasswd-pbkdf2' generates password hashes for GRUB
+(*note Security::).
+
+ grub-mkpasswd-pbkdf2
+
+ 'grub-mkpasswd-pbkdf2' accepts the following options:
+
+'-c NUMBER'
+'--iteration-count=NUMBER'
+ Number of iterations of the underlying pseudo-random function.
+ Defaults to 10000.
+
+'-l NUMBER'
+'--buflen=NUMBER'
+ Length of the generated hash. Defaults to 64.
+
+'-s NUMBER'
+'--salt=NUMBER'
+ Length of the salt. Defaults to 64.
+
+
+File: grub.info, Node: Invoking grub-mkrelpath, Next: Invoking grub-mkrescue, Prev: Invoking grub-mkpasswd-pbkdf2, Up: Top
+
+26 Invoking grub-mkrelpath
+**************************
+
+The program 'grub-mkrelpath' makes a file system path relative to the
+root of its containing file system. For instance, if '/usr' is a mount
+point, then:
+
+ $ grub-mkrelpath /usr/share/grub/unicode.pf2
+ '/share/grub/unicode.pf2'
+
+ This is mainly used internally by other GRUB utilities such as
+'grub-mkconfig' (*note Invoking grub-mkconfig::), but may occasionally
+also be useful for debugging.
+
+ 'grub-mkrelpath' accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+
+File: grub.info, Node: Invoking grub-mkrescue, Next: Invoking grub-mount, Prev: Invoking grub-mkrelpath, Up: Top
+
+27 Invoking grub-mkrescue
+*************************
+
+The program 'grub-mkrescue' generates a bootable GRUB rescue image
+(*note Making a GRUB bootable CD-ROM::).
+
+ grub-mkrescue -o grub.iso
+
+ All arguments not explicitly listed as 'grub-mkrescue' options are
+passed on directly to 'xorriso' in 'mkisofs' emulation mode. Options
+passed to 'xorriso' will normally be interpreted as 'mkisofs' options;
+if the option '--' is used, then anything after that will be interpreted
+as native 'xorriso' options.
+
+ Non-option arguments specify additional source directories. This is
+commonly used to add extra files to the image:
+
+ mkdir -p disk/boot/grub
+ (add extra files to 'disk/boot/grub')
+ grub-mkrescue -o grub.iso disk
+
+ 'grub-mkrescue' accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+'-o FILE'
+'--output=FILE'
+ Save output in FILE. This "option" is required.
+
+'--modules=MODULES'
+ Pre-load the named GRUB modules in the image. Multiple entries in
+ MODULES should be separated by whitespace (so you will probably
+ need to quote this for your shell).
+
+'--rom-directory=DIR'
+ If generating images for the QEMU or Coreboot platforms, copy the
+ resulting 'qemu.img' or 'coreboot.elf' files respectively to the
+ DIR directory as well as including them in the image.
+
+'--xorriso=FILE'
+ Use FILE as the 'xorriso' program, rather than the built-in
+ default.
+
+'--grub-mkimage=FILE'
+ Use FILE as the 'grub-mkimage' program, rather than the built-in
+ default.
+
+
+File: grub.info, Node: Invoking grub-mount, Next: Invoking grub-probe, Prev: Invoking grub-mkrescue, Up: Top
+
+28 Invoking grub-mount
+**********************
+
+The program 'grub-mount' performs a read-only mount of any file system
+or file system image that GRUB understands, using GRUB's file system
+drivers via FUSE. (It is only available if FUSE development files were
+present when GRUB was built.) This has a number of uses:
+
+ * It provides a convenient way to check how GRUB will view a file
+ system at boot time. You can use normal command-line tools to
+ compare that view with that of your operating system, making it
+ easy to find bugs.
+
+ * It offers true read-only mounts. Linux does not have these for
+ journalling file systems, because it will always attempt to replay
+ the journal at mount time; while you can temporarily mark the block
+ device read-only to avoid this, that causes the mount to fail.
+ Since GRUB intentionally contains no code for writing to file
+ systems, it can easily provide a guaranteed read-only mount
+ mechanism.
+
+ * It allows you to examine any file system that GRUB understands
+ without needing to load additional modules into your running
+ kernel, which may be useful in constrained environments such as
+ installers.
+
+ * Since it can examine file system images (contained in regular
+ files) just as easily as file systems on block devices, you can use
+ it to inspect any file system image that GRUB understands with only
+ enough privileges to use FUSE, even if nobody has yet written a
+ FUSE module specifically for that file system type.
+
+ Using 'grub-mount' is normally as simple as:
+
+ grub-mount /dev/sda1 /mnt
+
+ 'grub-mount' must be given one or more images and a mount point as
+non-option arguments (if it is given more than one image, it will treat
+them as a RAID set), and also accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+'-C'
+'--crypto'
+ Mount encrypted devices, prompting for a passphrase if necessary.
+
+'-d STRING'
+'--debug=STRING'
+ Show debugging output for conditions matching STRING.
+
+'-K prompt|FILE'
+'--zfs-key=prompt|FILE'
+ Load a ZFS encryption key. If you use 'prompt' as the argument,
+ 'grub-mount' will read a passphrase from the terminal; otherwise,
+ it will read key material from the specified file.
+
+'-r DEVICE'
+'--root=DEVICE'
+ Set the GRUB root device to DEVICE. You do not normally need to
+ set this; 'grub-mount' will automatically set the root device to
+ the root of the supplied file system.
+
+ If DEVICE is just a number, then it will be treated as a partition
+ number within the supplied image. This means that, if you have an
+ image of an entire disk in 'disk.img', then you can use this
+ command to mount its second partition:
+
+ grub-mount -r 2 disk.img mount-point
+
+'-v'
+'--verbose'
+ Print verbose messages.
+
+
+File: grub.info, Node: Invoking grub-probe, Next: Invoking grub-script-check, Prev: Invoking grub-mount, Up: Top
+
+29 Invoking grub-probe
+**********************
+
+The program 'grub-probe' probes device information for a given path or
+device.
+
+ grub-probe --target=fs /boot/grub
+ grub-probe --target=drive --device /dev/sda1
+
+ 'grub-probe' must be given a path or device as a non-option argument,
+and also accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+'-d'
+'--device'
+ If this option is given, then the non-option argument is a system
+ device name (such as '/dev/sda1'), and 'grub-probe' will print
+ information about that device. If it is not given, then the
+ non-option argument is a filesystem path (such as '/boot/grub'),
+ and 'grub-probe' will print information about the device containing
+ that part of the filesystem.
+
+'-m FILE'
+'--device-map=FILE'
+ Use FILE as the device map (*note Device map::) rather than the
+ default, usually '/boot/grub/device.map'.
+
+'-t TARGET'
+'--target=TARGET'
+ Print information about the given path or device as defined by
+ TARGET. The available targets and their meanings are:
+
+ 'fs'
+ GRUB filesystem module.
+ 'fs_uuid'
+ Filesystem Universally Unique Identifier (UUID).
+ 'fs_label'
+ Filesystem label.
+ 'drive'
+ GRUB device name.
+ 'device'
+ System device name.
+ 'partmap'
+ GRUB partition map module.
+ 'abstraction'
+ GRUB abstraction module (e.g. 'lvm').
+ 'cryptodisk_uuid'
+ Crypto device UUID.
+ 'msdos_parttype'
+ MBR partition type code (two hexadecimal digits).
+ 'hints_string'
+ A string of platform search hints suitable for passing to the
+ 'search' command (*note search::).
+ 'bios_hints'
+ Search hints for the PC BIOS platform.
+ 'ieee1275_hints'
+ Search hints for the IEEE1275 platform.
+ 'baremetal_hints'
+ Search hints for platforms where disks are addressed directly
+ rather than via firmware.
+ 'efi_hints'
+ Search hints for the EFI platform.
+ 'arc_hints'
+ Search hints for the ARC platform.
+ 'compatibility_hint'
+ A guess at a reasonable GRUB drive name for this device, which
+ may be used as a fallback if the 'search' command fails.
+ 'disk'
+ System device name for the whole disk.
+
+'-v'
+'--verbose'
+ Print verbose messages.
+
+
+File: grub.info, Node: Invoking grub-script-check, Next: Obtaining and Building GRUB, Prev: Invoking grub-probe, Up: Top
+
+30 Invoking grub-script-check
+*****************************
+
+The program 'grub-script-check' takes a GRUB script file (*note
+Shell-like scripting::) and checks it for syntax errors, similar to
+commands such as 'sh -n'. It may take a PATH as a non-option argument;
+if none is supplied, it will read from standard input.
+
+ grub-script-check /boot/grub/grub.cfg
+
+ 'grub-script-check' accepts the following options:
+
+'--help'
+ Print a summary of the command-line options and exit.
+
+'--version'
+ Print the version number of GRUB and exit.
+
+'-v'
+'--verbose'
+ Print each line of input after reading it.
+
+
+File: grub.info, Node: Obtaining and Building GRUB, Next: Reporting bugs, Prev: Invoking grub-script-check, Up: Top
+
+Appendix A How to obtain and build GRUB
+***************************************
+
+ *Caution:* GRUB requires binutils-2.9.1.0.23 or later because the
+ GNU assembler has been changed so that it can produce real 16bits
+ machine code between 2.9.1 and 2.9.1.0.x. See
+ <http://sources.redhat.com/binutils/>, to obtain information on how
+ to get the latest version.
+
+ GRUB is available from the GNU alpha archive site
+<ftp://ftp.gnu.org/gnu/grub> or any of its mirrors. The file will be
+named grub-version.tar.gz. The current version is 2.06, so the file you
+should grab is:
+
+ <ftp://ftp.gnu.org/gnu/grub/grub-2.06.tar.gz>
+
+ To unbundle GRUB use the instruction:
+
+ zcat grub-2.06.tar.gz | tar xvf -
+
+ which will create a directory called 'grub-2.06' with all the
+sources. You can look at the file 'INSTALL' for detailed instructions
+on how to build and install GRUB, but you should be able to just do:
+
+ cd grub-2.06
+ ./configure
+ make install
+
+ Also, the latest version is available using Git. See
+<http://www.gnu.org/software/grub/grub-download.html> for more
+information.
+
+
+File: grub.info, Node: Reporting bugs, Next: Future, Prev: Obtaining and Building GRUB, Up: Top
+
+Appendix B Reporting bugs
+*************************
+
+These are the guideline for how to report bugs. Take a look at this
+list below before you submit bugs:
+
+ 1. Before getting unsettled, read this manual through and through.
+ Also, see the GNU GRUB FAQ
+ (http://www.gnu.org/software/grub/grub-faq.html).
+
+ 2. Always mention the information on your GRUB. The version number and
+ the configuration are quite important. If you build it yourself,
+ write the options specified to the configure script and your
+ operating system, including the versions of gcc and binutils.
+
+ 3. If you have trouble with the installation, inform us of how you
+ installed GRUB. Don't omit error messages, if any. Just 'GRUB
+ hangs up when it boots' is not enough.
+
+ The information on your hardware is also essential. These are
+ especially important: the geometries and the partition tables of
+ your hard disk drives and your BIOS.
+
+ 4. If GRUB cannot boot your operating system, write down _everything_
+ you see on the screen. Don't paraphrase them, like 'The foo OS
+ crashes with GRUB, even though it can boot with the bar boot loader
+ just fine'. Mention the commands you executed, the messages
+ printed by them, and information on your operating system including
+ the version number.
+
+ 5. Explain what you wanted to do. It is very useful to know your
+ purpose and your wish, and how GRUB didn't satisfy you.
+
+ 6. If you can investigate the problem yourself, please do. That will
+ give you and us much more information on the problem. Attaching a
+ patch is even better.
+
+ When you attach a patch, make the patch in unified diff format, and
+ write ChangeLog entries. But, even when you make a patch, don't
+ forget to explain the problem, so that we can understand what your
+ patch is for.
+
+ 7. Write down anything that you think might be related. Please
+ understand that we often need to reproduce the same problem you
+ encountered in our environment. So your information should be
+ sufficient for us to do the same thing--Don't forget that we cannot
+ see your computer directly. If you are not sure whether to state a
+ fact or leave it out, state it! Reporting too many things is much
+ better than omitting something important.
+
+ If you follow the guideline above, submit a report to the Bug
+Tracking System (http://savannah.gnu.org/bugs/?group=grub).
+Alternatively, you can submit a report via electronic mail to
+<bug-grub@gnu.org>, but we strongly recommend that you use the Bug
+Tracking System, because e-mail can be passed over easily.
+
+ Once we get your report, we will try to fix the bugs.
+
+
+File: grub.info, Node: Future, Next: Copying This Manual, Prev: Reporting bugs, Up: Top
+
+Appendix C Where GRUB will go
+*****************************
+
+GRUB 2 is now quite stable and used in many production systems. We are
+currently working towards a 2.0 release.
+
+ If you are interested in the development of GRUB 2, take a look at
+the homepage (http://www.gnu.org/software/grub/grub.html).
+
+
+File: grub.info, Node: Copying This Manual, Next: Index, Prev: Future, Up: Top
+
+Appendix D Copying This Manual
+******************************
+
+* Menu:
+
+* GNU Free Documentation License:: License for copying this manual.
+
+
+File: grub.info, Node: GNU Free Documentation License, Up: Copying This Manual
+
+D.1 GNU Free Documentation License
+==================================
+
+ Version 1.2, November 2002
+
+ Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
+ 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ 0. PREAMBLE
+
+ The purpose of this License is to make a manual, textbook, or other
+ functional and useful document "free" in the sense of freedom: to
+ assure everyone the effective freedom to copy and redistribute it,
+ with or without modifying it, either commercially or
+ noncommercially. Secondarily, this License preserves for the
+ author and publisher a way to get credit for their work, while not
+ being considered responsible for modifications made by others.
+
+ This License is a kind of "copyleft", which means that derivative
+ works of the document must themselves be free in the same sense.
+ It complements the GNU General Public License, which is a copyleft
+ license designed for free software.
+
+ We have designed this License in order to use it for manuals for
+ free software, because free software needs free documentation: a
+ free program should come with manuals providing the same freedoms
+ that the software does. But this License is not limited to
+ software manuals; it can be used for any textual work, regardless
+ of subject matter or whether it is published as a printed book. We
+ recommend this License principally for works whose purpose is
+ instruction or reference.
+
+ 1. APPLICABILITY AND DEFINITIONS
+
+ This License applies to any manual or other work, in any medium,
+ that contains a notice placed by the copyright holder saying it can
+ be distributed under the terms of this License. Such a notice
+ grants a world-wide, royalty-free license, unlimited in duration,
+ to use that work under the conditions stated herein. The
+ "Document", below, refers to any such manual or work. Any member
+ of the public is a licensee, and is addressed as "you". You accept
+ the license if you copy, modify or distribute the work in a way
+ requiring permission under copyright law.
+
+ A "Modified Version" of the Document means any work containing the
+ Document or a portion of it, either copied verbatim, or with
+ modifications and/or translated into another language.
+
+ A "Secondary Section" is a named appendix or a front-matter section
+ of the Document that deals exclusively with the relationship of the
+ publishers or authors of the Document to the Document's overall
+ subject (or to related matters) and contains nothing that could
+ fall directly within that overall subject. (Thus, if the Document
+ is in part a textbook of mathematics, a Secondary Section may not
+ explain any mathematics.) The relationship could be a matter of
+ historical connection with the subject or with related matters, or
+ of legal, commercial, philosophical, ethical or political position
+ regarding them.
+
+ The "Invariant Sections" are certain Secondary Sections whose
+ titles are designated, as being those of Invariant Sections, in the
+ notice that says that the Document is released under this License.
+ If a section does not fit the above definition of Secondary then it
+ is not allowed to be designated as Invariant. The Document may
+ contain zero Invariant Sections. If the Document does not identify
+ any Invariant Sections then there are none.
+
+ The "Cover Texts" are certain short passages of text that are
+ listed, as Front-Cover Texts or Back-Cover Texts, in the notice
+ that says that the Document is released under this License. A
+ Front-Cover Text may be at most 5 words, and a Back-Cover Text may
+ be at most 25 words.
+
+ A "Transparent" copy of the Document means a machine-readable copy,
+ represented in a format whose specification is available to the
+ general public, that is suitable for revising the document
+ straightforwardly with generic text editors or (for images composed
+ of pixels) generic paint programs or (for drawings) some widely
+ available drawing editor, and that is suitable for input to text
+ formatters or for automatic translation to a variety of formats
+ suitable for input to text formatters. A copy made in an otherwise
+ Transparent file format whose markup, or absence of markup, has
+ been arranged to thwart or discourage subsequent modification by
+ readers is not Transparent. An image format is not Transparent if
+ used for any substantial amount of text. A copy that is not
+ "Transparent" is called "Opaque".
+
+ Examples of suitable formats for Transparent copies include plain
+ ASCII without markup, Texinfo input format, LaTeX input format,
+ SGML or XML using a publicly available DTD, and standard-conforming
+ simple HTML, PostScript or PDF designed for human modification.
+ Examples of transparent image formats include PNG, XCF and JPG.
+ Opaque formats include proprietary formats that can be read and
+ edited only by proprietary word processors, SGML or XML for which
+ the DTD and/or processing tools are not generally available, and
+ the machine-generated HTML, PostScript or PDF produced by some word
+ processors for output purposes only.
+
+ The "Title Page" means, for a printed book, the title page itself,
+ plus such following pages as are needed to hold, legibly, the
+ material this License requires to appear in the title page. For
+ works in formats which do not have any title page as such, "Title
+ Page" means the text near the most prominent appearance of the
+ work's title, preceding the beginning of the body of the text.
+
+ A section "Entitled XYZ" means a named subunit of the Document
+ whose title either is precisely XYZ or contains XYZ in parentheses
+ following text that translates XYZ in another language. (Here XYZ
+ stands for a specific section name mentioned below, such as
+ "Acknowledgements", "Dedications", "Endorsements", or "History".)
+ To "Preserve the Title" of such a section when you modify the
+ Document means that it remains a section "Entitled XYZ" according
+ to this definition.
+
+ The Document may include Warranty Disclaimers next to the notice
+ which states that this License applies to the Document. These
+ Warranty Disclaimers are considered to be included by reference in
+ this License, but only as regards disclaiming warranties: any other
+ implication that these Warranty Disclaimers may have is void and
+ has no effect on the meaning of this License.
+
+ 2. VERBATIM COPYING
+
+ You may copy and distribute the Document in any medium, either
+ commercially or noncommercially, provided that this License, the
+ copyright notices, and the license notice saying this License
+ applies to the Document are reproduced in all copies, and that you
+ add no other conditions whatsoever to those of this License. You
+ may not use technical measures to obstruct or control the reading
+ or further copying of the copies you make or distribute. However,
+ you may accept compensation in exchange for copies. If you
+ distribute a large enough number of copies you must also follow the
+ conditions in section 3.
+
+ You may also lend copies, under the same conditions stated above,
+ and you may publicly display copies.
+
+ 3. COPYING IN QUANTITY
+
+ If you publish printed copies (or copies in media that commonly
+ have printed covers) of the Document, numbering more than 100, and
+ the Document's license notice requires Cover Texts, you must
+ enclose the copies in covers that carry, clearly and legibly, all
+ these Cover Texts: Front-Cover Texts on the front cover, and
+ Back-Cover Texts on the back cover. Both covers must also clearly
+ and legibly identify you as the publisher of these copies. The
+ front cover must present the full title with all words of the title
+ equally prominent and visible. You may add other material on the
+ covers in addition. Copying with changes limited to the covers, as
+ long as they preserve the title of the Document and satisfy these
+ conditions, can be treated as verbatim copying in other respects.
+
+ If the required texts for either cover are too voluminous to fit
+ legibly, you should put the first ones listed (as many as fit
+ reasonably) on the actual cover, and continue the rest onto
+ adjacent pages.
+
+ If you publish or distribute Opaque copies of the Document
+ numbering more than 100, you must either include a machine-readable
+ Transparent copy along with each Opaque copy, or state in or with
+ each Opaque copy a computer-network location from which the general
+ network-using public has access to download using public-standard
+ network protocols a complete Transparent copy of the Document, free
+ of added material. If you use the latter option, you must take
+ reasonably prudent steps, when you begin distribution of Opaque
+ copies in quantity, to ensure that this Transparent copy will
+ remain thus accessible at the stated location until at least one
+ year after the last time you distribute an Opaque copy (directly or
+ through your agents or retailers) of that edition to the public.
+
+ It is requested, but not required, that you contact the authors of
+ the Document well before redistributing any large number of copies,
+ to give them a chance to provide you with an updated version of the
+ Document.
+
+ 4. MODIFICATIONS
+
+ You may copy and distribute a Modified Version of the Document
+ under the conditions of sections 2 and 3 above, provided that you
+ release the Modified Version under precisely this License, with the
+ Modified Version filling the role of the Document, thus licensing
+ distribution and modification of the Modified Version to whoever
+ possesses a copy of it. In addition, you must do these things in
+ the Modified Version:
+
+ A. Use in the Title Page (and on the covers, if any) a title
+ distinct from that of the Document, and from those of previous
+ versions (which should, if there were any, be listed in the
+ History section of the Document). You may use the same title
+ as a previous version if the original publisher of that
+ version gives permission.
+
+ B. List on the Title Page, as authors, one or more persons or
+ entities responsible for authorship of the modifications in
+ the Modified Version, together with at least five of the
+ principal authors of the Document (all of its principal
+ authors, if it has fewer than five), unless they release you
+ from this requirement.
+
+ C. State on the Title page the name of the publisher of the
+ Modified Version, as the publisher.
+
+ D. Preserve all the copyright notices of the Document.
+
+ E. Add an appropriate copyright notice for your modifications
+ adjacent to the other copyright notices.
+
+ F. Include, immediately after the copyright notices, a license
+ notice giving the public permission to use the Modified
+ Version under the terms of this License, in the form shown in
+ the Addendum below.
+
+ G. Preserve in that license notice the full lists of Invariant
+ Sections and required Cover Texts given in the Document's
+ license notice.
+
+ H. Include an unaltered copy of this License.
+
+ I. Preserve the section Entitled "History", Preserve its Title,
+ and add to it an item stating at least the title, year, new
+ authors, and publisher of the Modified Version as given on the
+ Title Page. If there is no section Entitled "History" in the
+ Document, create one stating the title, year, authors, and
+ publisher of the Document as given on its Title Page, then add
+ an item describing the Modified Version as stated in the
+ previous sentence.
+
+ J. Preserve the network location, if any, given in the Document
+ for public access to a Transparent copy of the Document, and
+ likewise the network locations given in the Document for
+ previous versions it was based on. These may be placed in the
+ "History" section. You may omit a network location for a work
+ that was published at least four years before the Document
+ itself, or if the original publisher of the version it refers
+ to gives permission.
+
+ K. For any section Entitled "Acknowledgements" or "Dedications",
+ Preserve the Title of the section, and preserve in the section
+ all the substance and tone of each of the contributor
+ acknowledgements and/or dedications given therein.
+
+ L. Preserve all the Invariant Sections of the Document, unaltered
+ in their text and in their titles. Section numbers or the
+ equivalent are not considered part of the section titles.
+
+ M. Delete any section Entitled "Endorsements". Such a section
+ may not be included in the Modified Version.
+
+ N. Do not retitle any existing section to be Entitled
+ "Endorsements" or to conflict in title with any Invariant
+ Section.
+
+ O. Preserve any Warranty Disclaimers.
+
+ If the Modified Version includes new front-matter sections or
+ appendices that qualify as Secondary Sections and contain no
+ material copied from the Document, you may at your option designate
+ some or all of these sections as invariant. To do this, add their
+ titles to the list of Invariant Sections in the Modified Version's
+ license notice. These titles must be distinct from any other
+ section titles.
+
+ You may add a section Entitled "Endorsements", provided it contains
+ nothing but endorsements of your Modified Version by various
+ parties--for example, statements of peer review or that the text
+ has been approved by an organization as the authoritative
+ definition of a standard.
+
+ You may add a passage of up to five words as a Front-Cover Text,
+ and a passage of up to 25 words as a Back-Cover Text, to the end of
+ the list of Cover Texts in the Modified Version. Only one passage
+ of Front-Cover Text and one of Back-Cover Text may be added by (or
+ through arrangements made by) any one entity. If the Document
+ already includes a cover text for the same cover, previously added
+ by you or by arrangement made by the same entity you are acting on
+ behalf of, you may not add another; but you may replace the old
+ one, on explicit permission from the previous publisher that added
+ the old one.
+
+ The author(s) and publisher(s) of the Document do not by this
+ License give permission to use their names for publicity for or to
+ assert or imply endorsement of any Modified Version.
+
+ 5. COMBINING DOCUMENTS
+
+ You may combine the Document with other documents released under
+ this License, under the terms defined in section 4 above for
+ modified versions, provided that you include in the combination all
+ of the Invariant Sections of all of the original documents,
+ unmodified, and list them all as Invariant Sections of your
+ combined work in its license notice, and that you preserve all
+ their Warranty Disclaimers.
+
+ The combined work need only contain one copy of this License, and
+ multiple identical Invariant Sections may be replaced with a single
+ copy. If there are multiple Invariant Sections with the same name
+ but different contents, make the title of each such section unique
+ by adding at the end of it, in parentheses, the name of the
+ original author or publisher of that section if known, or else a
+ unique number. Make the same adjustment to the section titles in
+ the list of Invariant Sections in the license notice of the
+ combined work.
+
+ In the combination, you must combine any sections Entitled
+ "History" in the various original documents, forming one section
+ Entitled "History"; likewise combine any sections Entitled
+ "Acknowledgements", and any sections Entitled "Dedications". You
+ must delete all sections Entitled "Endorsements."
+
+ 6. COLLECTIONS OF DOCUMENTS
+
+ You may make a collection consisting of the Document and other
+ documents released under this License, and replace the individual
+ copies of this License in the various documents with a single copy
+ that is included in the collection, provided that you follow the
+ rules of this License for verbatim copying of each of the documents
+ in all other respects.
+
+ You may extract a single document from such a collection, and
+ distribute it individually under this License, provided you insert
+ a copy of this License into the extracted document, and follow this
+ License in all other respects regarding verbatim copying of that
+ document.
+
+ 7. AGGREGATION WITH INDEPENDENT WORKS
+
+ A compilation of the Document or its derivatives with other
+ separate and independent documents or works, in or on a volume of a
+ storage or distribution medium, is called an "aggregate" if the
+ copyright resulting from the compilation is not used to limit the
+ legal rights of the compilation's users beyond what the individual
+ works permit. When the Document is included in an aggregate, this
+ License does not apply to the other works in the aggregate which
+ are not themselves derivative works of the Document.
+
+ If the Cover Text requirement of section 3 is applicable to these
+ copies of the Document, then if the Document is less than one half
+ of the entire aggregate, the Document's Cover Texts may be placed
+ on covers that bracket the Document within the aggregate, or the
+ electronic equivalent of covers if the Document is in electronic
+ form. Otherwise they must appear on printed covers that bracket
+ the whole aggregate.
+
+ 8. TRANSLATION
+
+ Translation is considered a kind of modification, so you may
+ distribute translations of the Document under the terms of section
+ 4. Replacing Invariant Sections with translations requires special
+ permission from their copyright holders, but you may include
+ translations of some or all Invariant Sections in addition to the
+ original versions of these Invariant Sections. You may include a
+ translation of this License, and all the license notices in the
+ Document, and any Warranty Disclaimers, provided that you also
+ include the original English version of this License and the
+ original versions of those notices and disclaimers. In case of a
+ disagreement between the translation and the original version of
+ this License or a notice or disclaimer, the original version will
+ prevail.
+
+ If a section in the Document is Entitled "Acknowledgements",
+ "Dedications", or "History", the requirement (section 4) to
+ Preserve its Title (section 1) will typically require changing the
+ actual title.
+
+ 9. TERMINATION
+
+ You may not copy, modify, sublicense, or distribute the Document
+ except as expressly provided for under this License. Any other
+ attempt to copy, modify, sublicense or distribute the Document is
+ void, and will automatically terminate your rights under this
+ License. However, parties who have received copies, or rights,
+ from you under this License will not have their licenses terminated
+ so long as such parties remain in full compliance.
+
+ 10. FUTURE REVISIONS OF THIS LICENSE
+
+ The Free Software Foundation may publish new, revised versions of
+ the GNU Free Documentation License from time to time. Such new
+ versions will be similar in spirit to the present version, but may
+ differ in detail to address new problems or concerns. See
+ <http://www.gnu.org/copyleft/>.
+
+ Each version of the License is given a distinguishing version
+ number. If the Document specifies that a particular numbered
+ version of this License "or any later version" applies to it, you
+ have the option of following the terms and conditions either of
+ that specified version or of any later version that has been
+ published (not as a draft) by the Free Software Foundation. If the
+ Document does not specify a version number of this License, you may
+ choose any version ever published (not as a draft) by the Free
+ Software Foundation.
+
+D.1.1 ADDENDUM: How to use this License for your documents
+----------------------------------------------------------
+
+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and license
+notices just after the title page:
+
+ Copyright (C) YEAR YOUR NAME.
+ Permission is granted to copy, distribute and/or modify this document
+ under the terms of the GNU Free Documentation License, Version 1.2
+ or any later version published by the Free Software Foundation;
+ with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
+ Texts. A copy of the license is included in the section entitled ``GNU
+ Free Documentation License''.
+
+ If you have Invariant Sections, Front-Cover Texts and Back-Cover
+Texts, replace the "with...Texts." line with this:
+
+ with the Invariant Sections being LIST THEIR TITLES, with
+ the Front-Cover Texts being LIST, and with the Back-Cover Texts
+ being LIST.
+
+ If you have Invariant Sections without Cover Texts, or some other
+combination of the three, merge those two alternatives to suit the
+situation.
+
+ If your document contains nontrivial examples of program code, we
+recommend releasing these examples in parallel under your choice of free
+software license, such as the GNU General Public License, to permit
+their use in free software.
+
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