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Diffstat (limited to 'USAGE-4.6')
| -rw-r--r-- | USAGE-4.6 | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/USAGE-4.6 b/USAGE-4.6 new file mode 100644 index 0000000..fcc28dc --- /dev/null +++ b/USAGE-4.6 @@ -0,0 +1,94 @@ + SQUASHFS - A squashed read-only filesystem for Linux + + Copyright 2002-2023 Phillip Lougher <phillip@squashfs.org.uk> + + Released under the GPL licence (version 2 or later). + +Welcome to Squashfs-tools. Please read the CHANGES and README-4.6 files for the +added features and improvements. + +Squashfs is a highly compressed read-only filesystem for Linux. +It uses either gzip/xz/lzo/lz4/zstd compression to compress both files, inodes +and directories. Inodes in the system are very small and all blocks are +packed to minimise data overhead. Block sizes greater than 4K are supported +up to a maximum of 1Mbytes (default block size 128K). + +Squashfs is intended for general read-only filesystem use, for archival +use (i.e. in cases where a .tar.gz file may be used), and in constrained +block device/memory systems (e.g. embedded systems) where low overhead is +needed. + +1. SQUASHFS AND TOOLS OVERVIEW +------------------------------ + +1. Data, inodes and directories can be compressed. + +2. Squashfs stores full uid/gids (32 bits), and file creation time. + +3. In theory files up to 2^64 bytes are supported. In theory filesystems can + be up to 2^64 bytes. + +4. Inode and directory data are highly compacted, and packed on byte + boundaries. Each compressed inode is on average 8 bytes in length + (the exact length varies on file type, i.e. regular file, directory, + symbolic link, and block/char device inodes have different sizes). + +5. Squashfs can use block sizes up to 1Mbyte (the default size is 128K). + Using 128K blocks achieves greater compression ratios than the normal + 4K block size. + +6. File duplicates are detected and removed. + +7. Filesystems can be compressed with gzip, xz (lzma2), lzo, lz4 + or zstd compression algorithms. + +8. Pseudo files are supported by Mksquashfs/Sqfstar which allow files which + don't exist in the source filesystem to be created on-demand. + +9. Creation of Squashfs filesystems from TAR archives is supported using + Sqfstar or the -tar option of Mksquashfs. + +10. External attributes are supported, and there are a full range of options + to filter attributes on filesystem creation and extraction, and additional + external attributes can be created which don't exist in the source + filesystem. + + +2. SQUASHFS TOOLS AVAILABLE +--------------------------- + +The Squashfs-tools consists of 4 programs. + +1. MKSQUASHFS + +This tool creates Squashfs filesystems from a set of source files and +directories. The file USAGE-MKSQUASHFS-4.6 describes how to use this +program. The (once installed) mksquashfs manpage contains more brief +information and a lot of usage examples. + +2. UNSQUASHFS + +This tool allows you to extract and list the contents of Squashfs +filesystems without mounting. The file USAGE-UNSQUASHFS-4.6 describes +how to use this program. The (once installed) unsquashfs manpage contains +more brief information and a lot of usage examples. + +3. SQFSTAR + +This tool creates Squashfs filesystems from a TAR archive. The file +USAGE-SQFSTAR-4.6 describes how to use this program. The (once installed) +sqfstar manpage contains more brief information and a lot of usage examples. + +4. SQFSCAT + +This program allows you to "cat" files to STDOUT from a Squashfs filesystem. +USAGE-SQFSCAT-4.6 describes how to use this program. The (once installed) +sqfscat manpage contains more brief information and a lot of usage examples. + +3. SUMMARY OF USAGE FILES +------------------------- + +For MKSQUASHFS see USAGE-MKSQUASHFS-4.6 +For UNSQUASHFS see USAGE-UNSQUASHFS-4.6 +For SQFSTAR see USAGE-SQFSTAR-4.6 +For SQFSCAT see USAGE-SQFSCAT-4.6 |