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-rw-r--r--man/man5/faillog.564
-rw-r--r--man/man5/gshadow.5101
-rw-r--r--man/man5/limits.5274
-rw-r--r--man/man5/login.access.567
-rw-r--r--man/man5/login.defs.5854
-rw-r--r--man/man5/passwd.5193
-rw-r--r--man/man5/porttime.596
-rw-r--r--man/man5/shadow.5148
-rw-r--r--man/man5/suauth.5146
-rw-r--r--man/man5/subgid.5100
-rw-r--r--man/man5/subuid.5100
11 files changed, 2143 insertions, 0 deletions
diff --git a/man/man5/faillog.5 b/man/man5/faillog.5
new file mode 100644
index 0000000..1264619
--- /dev/null
+++ b/man/man5/faillog.5
@@ -0,0 +1,64 @@
+'\" t
+.\" Title: faillog
+.\" Author: Julianne Frances Haugh
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "FAILLOG" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+faillog \- login failure logging file
+.SH "DESCRIPTION"
+.PP
+/var/log/faillog
+maintains a count of login failures and the limits for each account\&.
+.PP
+The file contains fixed length records, indexed by numerical UID\&. Each record contains the count of login failures since the last successful login; the maximum number of failures before the account is disabled; the line on which the last login failure occurred; the date of the last login failure; and the duration (in seconds) during which the account will be locked after a failure\&.
+.PP
+The structure of the file is:
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+struct faillog {
+ short fail_cnt;
+ short fail_max;
+ char fail_line[12];
+ time_t fail_time;
+ long fail_locktime;
+};
+.fi
+.if n \{\
+.RE
+.\}
+.SH "FILES"
+.PP
+/var/log/faillog
+.RS 4
+Failure logging file\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBfaillog\fR(8)
diff --git a/man/man5/gshadow.5 b/man/man5/gshadow.5
new file mode 100644
index 0000000..d657c58
--- /dev/null
+++ b/man/man5/gshadow.5
@@ -0,0 +1,101 @@
+'\" t
+.\" Title: gshadow
+.\" Author: Nicolas François <nicolas.francois@centraliens.net>
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "GSHADOW" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+gshadow \- shadowed group file
+.SH "DESCRIPTION"
+.PP
+/etc/gshadow
+contains the shadowed information for group accounts\&.
+.PP
+This file must not be readable by regular users if password security is to be maintained\&.
+.PP
+Each line of this file contains the following colon\-separated fields:
+.PP
+\fBgroup name\fR
+.RS 4
+It must be a valid group name, which exist on the system\&.
+.RE
+.PP
+\fBencrypted password\fR
+.RS 4
+Refer to
+\fBcrypt\fR(3)
+for details on how this string is interpreted\&.
+.sp
+If the password field contains some string that is not a valid result of
+\fBcrypt\fR(3), for instance ! or *, users will not be able to use a unix password to access the group (but group members do not need the password)\&.
+.sp
+The password is used when a user who is not a member of the group wants to gain the permissions of this group (see
+\fBnewgrp\fR(1))\&.
+.sp
+This field may be empty, in which case only the group members can gain the group permissions\&.
+.sp
+A password field which starts with an exclamation mark means that the password is locked\&. The remaining characters on the line represent the password field before the password was locked\&.
+.sp
+This password supersedes any password specified in
+/etc/group\&.
+.RE
+.PP
+\fBadministrators\fR
+.RS 4
+It must be a comma\-separated list of user names\&.
+.sp
+Administrators can change the password or the members of the group\&.
+.sp
+Administrators also have the same permissions as the members (see below)\&.
+.RE
+.PP
+\fBmembers\fR
+.RS 4
+It must be a comma\-separated list of user names\&.
+.sp
+Members can access the group without being prompted for a password\&.
+.sp
+You should use the same list of users as in
+/etc/group\&.
+.RE
+.SH "FILES"
+.PP
+/etc/group
+.RS 4
+Group account information\&.
+.RE
+.PP
+/etc/gshadow
+.RS 4
+Secure group account information\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBgpasswd\fR(5),
+\fBgroup\fR(5),
+\fBgrpck\fR(8),
+\fBgrpconv\fR(8),
+\fBnewgrp\fR(1)\&.
diff --git a/man/man5/limits.5 b/man/man5/limits.5
new file mode 100644
index 0000000..ad3f734
--- /dev/null
+++ b/man/man5/limits.5
@@ -0,0 +1,274 @@
+'\" t
+.\" Title: limits
+.\" Author: Luca Berra
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "LIMITS" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+limits \- resource limits definition
+.SH "DESCRIPTION"
+.PP
+The
+\fIlimits\fR
+file (/etc/limits
+by default or LIMITS_FILE defined
+config\&.h) describes the resource limits you wish to impose\&. It should be owned by root and readable by root account only\&.
+.PP
+By default no quota is imposed on \*(Aqroot\*(Aq\&. In fact, there is no way to impose limits via this procedure to root\-equiv accounts (accounts with UID 0)\&.
+.PP
+Each line describes a limit for a user in the form:
+.PP
+\fIuser LIMITS_STRING\fR
+.PP
+or in the form:
+.PP
+\fI@group LIMITS_STRING\fR
+.PP
+The
+\fILIMITS_STRING\fR
+is a string of a concatenated list of resource limits\&. Each limit consists of a letter identifier followed by a numerical limit\&.
+.PP
+The valid identifiers are:
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+A: max address space (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+C: max core file size (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+D: max data size (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+F: maximum file size (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+K: file creation mask, set by
+\fBumask\fR(2)\&.
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+I: max nice value (0\&.\&.39 which translates to 20\&.\&.\-19)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+L: max number of logins for this user
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+M: max locked\-in\-memory address space (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+N: max number of open files
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+O: max real time priority
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+P: process priority, set by
+\fBsetpriority\fR(2)\&.
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+R: max resident set size (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+S: max stack size (KB)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+T: max CPU time (MIN)
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+U: max number of processes
+.RE
+.PP
+For example,
+\fIL2D2048N5\fR
+is a valid
+\fILIMITS_STRING\fR\&. For reading convenience, the following entries are equivalent:
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+ username L2D2048N5
+ username L2 D2048 N5
+
+.fi
+.if n \{\
+.RE
+.\}
+.PP
+Be aware that after
+\fIusername\fR
+the rest of the line is considered a limit string, thus comments are not allowed\&. An invalid limits string will be rejected (not considered) by the
+\fBlogin\fR
+program\&.
+.PP
+The default entry is denoted by username "\fI*\fR"\&. If you have multiple
+\fIdefault\fR
+entries in your
+\fILIMITS_FILE\fR, then the last one will be used as the default entry\&.
+.PP
+The limits specified in the form "\fI@group\fR" apply to the members of the specified
+\fIgroup\fR\&.
+.PP
+If more than one line with limits for a user exist, only the first line for this user will be considered\&.
+.PP
+If no lines are specified for a user, the last
+\fI@group\fR
+line matching a group whose the user is a member of will be considered, or the last line with default limits if no groups contain the user\&.
+.PP
+To completely disable limits for a user, a single dash "\fI\-\fR" will do\&.
+.PP
+To disable a limit for a user, a single dash "\fI\-\fR" can be used instead of the numerical value for this limit\&.
+.PP
+Also, please note that all limit settings are set PER LOGIN\&. They are not global, nor are they permanent\&. Perhaps global limits will come, but for now this will have to do ;)
+.SH "FILES"
+.PP
+/etc/limits
+.RS 4
+.RE
+.SH "SEE ALSO"
+.PP
+\fBlogin\fR(1),
+\fBsetpriority\fR(2),
+\fBsetrlimit\fR(2)\&.
diff --git a/man/man5/login.access.5 b/man/man5/login.access.5
new file mode 100644
index 0000000..81e79ba
--- /dev/null
+++ b/man/man5/login.access.5
@@ -0,0 +1,67 @@
+'\" t
+.\" Title: login.access
+.\" Author: Marek Michałkiewicz
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "LOGIN\&.ACCESS" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+login.access \- login access control table
+.SH "DESCRIPTION"
+.PP
+The
+\fIlogin\&.access\fR
+file specifies (user, host) combinations and/or (user, tty) combinations for which a login will be either accepted or refused\&.
+.PP
+When someone logs in, the
+\fIlogin\&.access\fR
+is scanned for the first entry that matches the (user, host) combination, or, in case of non\-networked logins, the first entry that matches the (user, tty) combination\&. The permissions field of that table entry determines whether the login will be accepted or refused\&.
+.PP
+Each line of the login access control table has three fields separated by a ":" character:
+.PP
+\fIpermission\fR:\fIusers\fR:\fIorigins\fR
+.PP
+The first field should be a "\fI+\fR" (access granted) or "\fI\-\fR" (access denied) character\&. The second field should be a list of one or more login names, group names, or
+\fIALL\fR
+(always matches)\&. The third field should be a list of one or more tty names (for non\-networked logins), host names, domain names (begin with "\&."), host addresses, internet network numbers (end with "\&."),
+\fIALL\fR
+(always matches) or
+\fILOCAL\fR
+(matches any string that does not contain a "\&." character)\&. If you run NIS you can use @netgroupname in host or user patterns\&.
+.PP
+The
+\fIEXCEPT\fR
+operator makes it possible to write very compact rules\&.
+.PP
+The group file is searched only when a name does not match that of the logged\-in user\&. Only groups are matched in which users are explicitly listed: the program does not look at a user\*(Aqs primary group id value\&.
+.SH "FILES"
+.PP
+/etc/login\&.defs
+.RS 4
+Shadow password suite configuration\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBlogin\fR(1)\&.
diff --git a/man/man5/login.defs.5 b/man/man5/login.defs.5
new file mode 100644
index 0000000..3ac322f
--- /dev/null
+++ b/man/man5/login.defs.5
@@ -0,0 +1,854 @@
+'\" t
+.\" Title: login.defs
+.\" Author: Julianne Frances Haugh
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "LOGIN\&.DEFS" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+login.defs \- shadow password suite configuration
+.SH "DESCRIPTION"
+.PP
+The
+/etc/login\&.defs
+file defines the site\-specific configuration for the shadow password suite\&. This file is required\&. Absence of this file will not prevent system operation, but will probably result in undesirable operation\&.
+.PP
+This file is a readable text file, each line of the file describing one configuration parameter\&. The lines consist of a configuration name and value, separated by whitespace\&. Blank lines and comment lines are ignored\&. Comments are introduced with a "#" pound sign and the pound sign must be the first non\-white character of the line\&.
+.PP
+Parameter values may be of four types: strings, booleans, numbers, and long numbers\&. A string is comprised of any printable characters\&. A boolean should be either the value
+\fIyes\fR
+or
+\fIno\fR\&. An undefined boolean parameter or one with a value other than these will be given a
+\fIno\fR
+value\&. Numbers (both regular and long) may be either decimal values, octal values (precede the value with
+\fI0\fR) or hexadecimal values (precede the value with
+\fI0x\fR)\&. The maximum value of the regular and long numeric parameters is machine\-dependent\&.
+.PP
+The following configuration items are provided:
+.PP
+\fBCHFN_AUTH\fR (boolean)
+.RS 4
+If
+\fIyes\fR, the
+\fBchfn\fR
+program will require authentication before making any changes, unless run by the superuser\&.
+.RE
+.PP
+\fBCHFN_RESTRICT\fR (string)
+.RS 4
+This parameter specifies which values in the
+\fIgecos\fR
+field of the
+/etc/passwd
+file may be changed by regular users using the
+\fBchfn\fR
+program\&. It can be any combination of letters
+\fIf\fR,
+\fIr\fR,
+\fIw\fR,
+\fIh\fR, for Full name, Room number, Work phone, and Home phone, respectively\&. For backward compatibility,
+\fIyes\fR
+is equivalent to
+\fIrwh\fR
+and
+\fIno\fR
+is equivalent to
+\fIfrwh\fR\&. If not specified, only the superuser can make any changes\&. The most restrictive setting is better achieved by not installing
+\fBchfn\fR
+SUID\&.
+.RE
+.PP
+\fBCHSH_AUTH\fR (boolean)
+.RS 4
+If
+\fIyes\fR, the
+\fBchsh\fR
+program will require authentication before making any changes, unless run by the superuser\&.
+.RE
+.PP
+\fBCONSOLE\fR (string)
+.RS 4
+If defined, either full pathname of a file containing device names (one per line) or a ":" delimited list of device names\&. Root logins will be allowed only upon these devices\&.
+.sp
+If not defined, root will be allowed on any device\&.
+.sp
+The device should be specified without the /dev/ prefix\&.
+.RE
+.PP
+\fBCONSOLE_GROUPS\fR (string)
+.RS 4
+List of groups to add to the user\*(Aqs supplementary groups set when logging in on the console (as determined by the CONSOLE setting)\&. Default is none\&.
+
+Use with caution \- it is possible for users to gain permanent access to these groups, even when not logged in on the console\&.
+.RE
+.PP
+\fBCREATE_HOME\fR (boolean)
+.RS 4
+Indicate if a home directory should be created by default for new users\&.
+.sp
+This setting does not apply to system users, and can be overridden on the command line\&.
+.RE
+.PP
+\fBDEFAULT_HOME\fR (boolean)
+.RS 4
+Indicate if login is allowed if we can\*(Aqt cd to the home directory\&. Default is no\&.
+.sp
+If set to
+\fIyes\fR, the user will login in the root (/) directory if it is not possible to cd to her home directory\&.
+.RE
+.PP
+\fBENCRYPT_METHOD\fR (string)
+.RS 4
+This defines the system default encryption algorithm for encrypting passwords (if no algorithm are specified on the command line)\&.
+.sp
+It can take one of these values:
+\fIDES\fR
+(default),
+\fIMD5\fR, \fISHA256\fR, \fISHA512\fR\&.
+.sp
+Note: this parameter overrides the
+\fBMD5_CRYPT_ENAB\fR
+variable\&.
+.RE
+.PP
+\fBENV_HZ\fR (string)
+.RS 4
+If set, it will be used to define the HZ environment variable when a user login\&. The value must be preceded by
+\fIHZ=\fR\&. A common value on Linux is
+\fIHZ=100\fR\&.
+.RE
+.PP
+\fBENV_PATH\fR (string)
+.RS 4
+If set, it will be used to define the PATH environment variable when a regular user login\&. The value is a colon separated list of paths (for example
+\fI/bin:/usr/bin\fR) and can be preceded by
+\fIPATH=\fR\&. The default value is
+\fIPATH=/bin:/usr/bin\fR\&.
+.RE
+.PP
+\fBENV_SUPATH\fR (string)
+.RS 4
+If set, it will be used to define the PATH environment variable when the superuser login\&. The value is a colon separated list of paths (for example
+\fI/sbin:/bin:/usr/sbin:/usr/bin\fR) and can be preceded by
+\fIPATH=\fR\&. The default value is
+\fIPATH=/sbin:/bin:/usr/sbin:/usr/bin\fR\&.
+.RE
+.PP
+\fBENV_TZ\fR (string)
+.RS 4
+If set, it will be used to define the TZ environment variable when a user login\&. The value can be the name of a timezone preceded by
+\fITZ=\fR
+(for example
+\fITZ=CST6CDT\fR), or the full path to the file containing the timezone specification (for example
+/etc/tzname)\&.
+.sp
+If a full path is specified but the file does not exist or cannot be read, the default is to use
+\fITZ=CST6CDT\fR\&.
+.RE
+.PP
+\fBENVIRON_FILE\fR (string)
+.RS 4
+If this file exists and is readable, login environment will be read from it\&. Every line should be in the form name=value\&.
+.sp
+Lines starting with a # are treated as comment lines and ignored\&.
+.RE
+.PP
+\fBERASECHAR\fR (number)
+.RS 4
+Terminal ERASE character (\fI010\fR
+= backspace,
+\fI0177\fR
+= DEL)\&.
+.sp
+The value can be prefixed "0" for an octal value, or "0x" for an hexadecimal value\&.
+.RE
+.PP
+\fBFAIL_DELAY\fR (number)
+.RS 4
+Delay in seconds before being allowed another attempt after a login failure\&.
+.RE
+.PP
+\fBFAILLOG_ENAB\fR (boolean)
+.RS 4
+Enable logging and display of
+/var/log/faillog
+login failure info\&.
+.RE
+.PP
+\fBFAKE_SHELL\fR (string)
+.RS 4
+If set,
+\fBlogin\fR
+will execute this shell instead of the users\*(Aq shell specified in
+/etc/passwd\&.
+.RE
+.PP
+\fBFTMP_FILE\fR (string)
+.RS 4
+If defined, login failures will be logged in this file in a utmp format\&.
+.RE
+.PP
+\fBGID_MAX\fR (number), \fBGID_MIN\fR (number)
+.RS 4
+Range of group IDs used for the creation of regular groups by
+\fBuseradd\fR,
+\fBgroupadd\fR, or
+\fBnewusers\fR\&.
+.sp
+The default value for
+\fBGID_MIN\fR
+(resp\&.
+\fBGID_MAX\fR) is 1000 (resp\&. 60000)\&.
+.RE
+.PP
+\fBHOME_MODE\fR (number)
+.RS 4
+The mode for new home directories\&. If not specified, the
+\fBUMASK\fR
+is used to create the mode\&.
+.sp
+\fBuseradd\fR
+and
+\fBnewusers\fR
+use this to set the mode of the home directory they create\&.
+.RE
+.PP
+\fBHUSHLOGIN_FILE\fR (string)
+.RS 4
+If defined, this file can inhibit all the usual chatter during the login sequence\&. If a full pathname is specified, then hushed mode will be enabled if the user\*(Aqs name or shell are found in the file\&. If not a full pathname, then hushed mode will be enabled if the file exists in the user\*(Aqs home directory\&.
+.RE
+.PP
+\fBISSUE_FILE\fR (string)
+.RS 4
+If defined, this file will be displayed before each login prompt\&.
+.RE
+.PP
+\fBKILLCHAR\fR (number)
+.RS 4
+Terminal KILL character (\fI025\fR
+= CTRL/U)\&.
+.sp
+The value can be prefixed "0" for an octal value, or "0x" for an hexadecimal value\&.
+.RE
+.PP
+\fBLASTLOG_ENAB\fR (boolean)
+.RS 4
+Enable logging and display of /var/log/lastlog login time info\&.
+.RE
+.PP
+\fBLASTLOG_UID_MAX\fR (number)
+.RS 4
+Highest user ID number for which the lastlog entries should be updated\&. As higher user IDs are usually tracked by remote user identity and authentication services there is no need to create a huge sparse lastlog file for them\&.
+.sp
+No
+\fBLASTLOG_UID_MAX\fR
+option present in the configuration means that there is no user ID limit for writing lastlog entries\&.
+.RE
+.PP
+\fBLOG_OK_LOGINS\fR (boolean)
+.RS 4
+Enable logging of successful logins\&.
+.RE
+.PP
+\fBLOG_UNKFAIL_ENAB\fR (boolean)
+.RS 4
+Enable display of unknown usernames when login failures are recorded\&.
+.sp
+Note: logging unknown usernames may be a security issue if an user enter her password instead of her login name\&.
+.RE
+.PP
+\fBLOGIN_RETRIES\fR (number)
+.RS 4
+Maximum number of login retries in case of bad password\&.
+.RE
+.PP
+\fBLOGIN_STRING\fR (string)
+.RS 4
+The string used for prompting a password\&. The default is to use "Password: ", or a translation of that string\&. If you set this variable, the prompt will not be translated\&.
+.sp
+If the string contains
+\fI%s\fR, this will be replaced by the user\*(Aqs name\&.
+.RE
+.PP
+\fBLOGIN_TIMEOUT\fR (number)
+.RS 4
+Max time in seconds for login\&.
+.RE
+.PP
+\fBMAIL_CHECK_ENAB\fR (boolean)
+.RS 4
+Enable checking and display of mailbox status upon login\&.
+.sp
+You should disable it if the shell startup files already check for mail ("mailx \-e" or equivalent)\&.
+.RE
+.PP
+\fBMAIL_DIR\fR (string)
+.RS 4
+The mail spool directory\&. This is needed to manipulate the mailbox when its corresponding user account is modified or deleted\&. If not specified, a compile\-time default is used\&.
+.RE
+.PP
+\fBMAIL_FILE\fR (string)
+.RS 4
+Defines the location of the users mail spool files relatively to their home directory\&.
+.RE
+.PP
+The
+\fBMAIL_DIR\fR
+and
+\fBMAIL_FILE\fR
+variables are used by
+\fBuseradd\fR,
+\fBusermod\fR, and
+\fBuserdel\fR
+to create, move, or delete the user\*(Aqs mail spool\&.
+.PP
+If
+\fBMAIL_CHECK_ENAB\fR
+is set to
+\fIyes\fR, they are also used to define the
+\fBMAIL\fR
+environment variable\&.
+.PP
+\fBMAX_MEMBERS_PER_GROUP\fR (number)
+.RS 4
+Maximum members per group entry\&. When the maximum is reached, a new group entry (line) is started in
+/etc/group
+(with the same name, same password, and same GID)\&.
+.sp
+The default value is 0, meaning that there are no limits in the number of members in a group\&.
+.sp
+This feature (split group) permits to limit the length of lines in the group file\&. This is useful to make sure that lines for NIS groups are not larger than 1024 characters\&.
+.sp
+If you need to enforce such limit, you can use 25\&.
+.sp
+Note: split groups may not be supported by all tools (even in the Shadow toolsuite)\&. You should not use this variable unless you really need it\&.
+.RE
+.PP
+\fBMD5_CRYPT_ENAB\fR (boolean)
+.RS 4
+Indicate if passwords must be encrypted using the MD5\-based algorithm\&. If set to
+\fIyes\fR, new passwords will be encrypted using the MD5\-based algorithm compatible with the one used by recent releases of FreeBSD\&. It supports passwords of unlimited length and longer salt strings\&. Set to
+\fIno\fR
+if you need to copy encrypted passwords to other systems which don\*(Aqt understand the new algorithm\&. Default is
+\fIno\fR\&.
+.sp
+This variable is superseded by the
+\fBENCRYPT_METHOD\fR
+variable or by any command line option used to configure the encryption algorithm\&.
+.sp
+This variable is deprecated\&. You should use
+\fBENCRYPT_METHOD\fR\&.
+.RE
+.PP
+\fBMOTD_FILE\fR (string)
+.RS 4
+If defined, ":" delimited list of "message of the day" files to be displayed upon login\&.
+.RE
+.PP
+\fBNOLOGINS_FILE\fR (string)
+.RS 4
+If defined, name of file whose presence will inhibit non\-root logins\&. The contents of this file should be a message indicating why logins are inhibited\&.
+.RE
+.PP
+\fBOBSCURE_CHECKS_ENAB\fR (boolean)
+.RS 4
+Enable additional checks upon password changes\&.
+.RE
+.PP
+\fBPASS_ALWAYS_WARN\fR (boolean)
+.RS 4
+Warn about weak passwords (but still allow them) if you are root\&.
+.RE
+.PP
+\fBPASS_CHANGE_TRIES\fR (number)
+.RS 4
+Maximum number of attempts to change password if rejected (too easy)\&.
+.RE
+.PP
+\fBPASS_MAX_DAYS\fR (number)
+.RS 4
+The maximum number of days a password may be used\&. If the password is older than this, a password change will be forced\&. If not specified, \-1 will be assumed (which disables the restriction)\&.
+.RE
+.PP
+\fBPASS_MIN_DAYS\fR (number)
+.RS 4
+The minimum number of days allowed between password changes\&. Any password changes attempted sooner than this will be rejected\&. If not specified, \-1 will be assumed (which disables the restriction)\&.
+.RE
+.PP
+\fBPASS_WARN_AGE\fR (number)
+.RS 4
+The number of days warning given before a password expires\&. A zero means warning is given only upon the day of expiration, a negative value means no warning is given\&. If not specified, no warning will be provided\&.
+.RE
+.PP
+\fBPASS_MAX_DAYS\fR,
+\fBPASS_MIN_DAYS\fR
+and
+\fBPASS_WARN_AGE\fR
+are only used at the time of account creation\&. Any changes to these settings won\*(Aqt affect existing accounts\&.
+.PP
+\fBPASS_MAX_LEN\fR (number), \fBPASS_MIN_LEN\fR (number)
+.RS 4
+Number of significant characters in the password for crypt()\&.
+\fBPASS_MAX_LEN\fR
+is 8 by default\&. Don\*(Aqt change unless your crypt() is better\&. This is ignored if
+\fBMD5_CRYPT_ENAB\fR
+set to
+\fIyes\fR\&.
+.RE
+.PP
+\fBPORTTIME_CHECKS_ENAB\fR (boolean)
+.RS 4
+Enable checking of time restrictions specified in
+/etc/porttime\&.
+.RE
+.PP
+\fBQUOTAS_ENAB\fR (boolean)
+.RS 4
+Enable setting of resource limits from
+/etc/limits
+and ulimit, umask, and niceness from the user\*(Aqs passwd gecos field\&.
+.RE
+.PP
+\fBSHA_CRYPT_MIN_ROUNDS\fR (number), \fBSHA_CRYPT_MAX_ROUNDS\fR (number)
+.RS 4
+When
+\fBENCRYPT_METHOD\fR
+is set to
+\fISHA256\fR
+or
+\fISHA512\fR, this defines the number of SHA rounds used by the encryption algorithm by default (when the number of rounds is not specified on the command line)\&.
+.sp
+With a lot of rounds, it is more difficult to brute forcing the password\&. But note also that more CPU resources will be needed to authenticate users\&.
+.sp
+If not specified, the libc will choose the default number of rounds (5000)\&.
+.sp
+The values must be inside the 1000\-999,999,999 range\&.
+.sp
+If only one of the
+\fBSHA_CRYPT_MIN_ROUNDS\fR
+or
+\fBSHA_CRYPT_MAX_ROUNDS\fR
+values is set, then this value will be used\&.
+.sp
+If
+\fBSHA_CRYPT_MIN_ROUNDS\fR
+>
+\fBSHA_CRYPT_MAX_ROUNDS\fR, the highest value will be used\&.
+.RE
+.PP
+\fBSULOG_FILE\fR (string)
+.RS 4
+If defined, all su activity is logged to this file\&.
+.RE
+.PP
+\fBSU_NAME\fR (string)
+.RS 4
+If defined, the command name to display when running "su \-"\&. For example, if this is defined as "su" then a "ps" will display the command is "\-su"\&. If not defined, then "ps" would display the name of the shell actually being run, e\&.g\&. something like "\-sh"\&.
+.RE
+.PP
+\fBSU_WHEEL_ONLY\fR (boolean)
+.RS 4
+If
+\fIyes\fR, the user must be listed as a member of the first gid 0 group in
+/etc/group
+(called
+\fIroot\fR
+on most Linux systems) to be able to
+\fBsu\fR
+to uid 0 accounts\&. If the group doesn\*(Aqt exist or is empty, no one will be able to
+\fBsu\fR
+to uid 0\&.
+.RE
+.PP
+\fBSUB_GID_MIN\fR (number), \fBSUB_GID_MAX\fR (number), \fBSUB_GID_COUNT\fR (number)
+.RS 4
+If
+/etc/subuid
+exists, the commands
+\fBuseradd\fR
+and
+\fBnewusers\fR
+(unless the user already have subordinate group IDs) allocate
+\fBSUB_GID_COUNT\fR
+unused group IDs from the range
+\fBSUB_GID_MIN\fR
+to
+\fBSUB_GID_MAX\fR
+for each new user\&.
+.sp
+The default values for
+\fBSUB_GID_MIN\fR,
+\fBSUB_GID_MAX\fR,
+\fBSUB_GID_COUNT\fR
+are respectively 100000, 600100000 and 65536\&.
+.RE
+.PP
+\fBSUB_UID_MIN\fR (number), \fBSUB_UID_MAX\fR (number), \fBSUB_UID_COUNT\fR (number)
+.RS 4
+If
+/etc/subuid
+exists, the commands
+\fBuseradd\fR
+and
+\fBnewusers\fR
+(unless the user already have subordinate user IDs) allocate
+\fBSUB_UID_COUNT\fR
+unused user IDs from the range
+\fBSUB_UID_MIN\fR
+to
+\fBSUB_UID_MAX\fR
+for each new user\&.
+.sp
+The default values for
+\fBSUB_UID_MIN\fR,
+\fBSUB_UID_MAX\fR,
+\fBSUB_UID_COUNT\fR
+are respectively 100000, 600100000 and 65536\&.
+.RE
+.PP
+\fBSYS_GID_MAX\fR (number), \fBSYS_GID_MIN\fR (number)
+.RS 4
+Range of group IDs used for the creation of system groups by
+\fBuseradd\fR,
+\fBgroupadd\fR, or
+\fBnewusers\fR\&.
+.sp
+The default value for
+\fBSYS_GID_MIN\fR
+(resp\&.
+\fBSYS_GID_MAX\fR) is 101 (resp\&.
+\fBGID_MIN\fR\-1)\&.
+.RE
+.PP
+\fBSYS_UID_MAX\fR (number), \fBSYS_UID_MIN\fR (number)
+.RS 4
+Range of user IDs used for the creation of system users by
+\fBuseradd\fR
+or
+\fBnewusers\fR\&.
+.sp
+The default value for
+\fBSYS_UID_MIN\fR
+(resp\&.
+\fBSYS_UID_MAX\fR) is 101 (resp\&.
+\fBUID_MIN\fR\-1)\&.
+.RE
+.PP
+\fBSYSLOG_SG_ENAB\fR (boolean)
+.RS 4
+Enable "syslog" logging of
+\fBsg\fR
+activity\&.
+.RE
+.PP
+\fBSYSLOG_SU_ENAB\fR (boolean)
+.RS 4
+Enable "syslog" logging of
+\fBsu\fR
+activity \- in addition to sulog file logging\&.
+.RE
+.PP
+\fBTTYGROUP\fR (string), \fBTTYPERM\fR (string)
+.RS 4
+The terminal permissions: the login tty will be owned by the
+\fBTTYGROUP\fR
+group, and the permissions will be set to
+\fBTTYPERM\fR\&.
+.sp
+By default, the ownership of the terminal is set to the user\*(Aqs primary group and the permissions are set to
+\fI0600\fR\&.
+.sp
+\fBTTYGROUP\fR
+can be either the name of a group or a numeric group identifier\&.
+.sp
+If you have a
+\fBwrite\fR
+program which is "setgid" to a special group which owns the terminals, define TTYGROUP to the group number and TTYPERM to 0620\&. Otherwise leave TTYGROUP commented out and assign TTYPERM to either 622 or 600\&.
+.RE
+.PP
+\fBTTYTYPE_FILE\fR (string)
+.RS 4
+If defined, file which maps tty line to TERM environment parameter\&. Each line of the file is in a format something like "vt100 tty01"\&.
+.RE
+.PP
+\fBUID_MAX\fR (number), \fBUID_MIN\fR (number)
+.RS 4
+Range of user IDs used for the creation of regular users by
+\fBuseradd\fR
+or
+\fBnewusers\fR\&.
+.sp
+The default value for
+\fBUID_MIN\fR
+(resp\&.
+\fBUID_MAX\fR) is 1000 (resp\&. 60000)\&.
+.RE
+.PP
+\fBULIMIT\fR (number)
+.RS 4
+Default
+\fBulimit\fR
+value\&.
+.RE
+.PP
+\fBUMASK\fR (number)
+.RS 4
+The file mode creation mask is initialized to this value\&. If not specified, the mask will be initialized to 022\&.
+.sp
+\fBuseradd\fR
+and
+\fBnewusers\fR
+use this mask to set the mode of the home directory they create if
+\fBHOME_MODE\fR
+is not set\&.
+.sp
+It is also used by
+\fBlogin\fR
+to define users\*(Aq initial umask\&. Note that this mask can be overridden by the user\*(Aqs GECOS line (if
+\fBQUOTAS_ENAB\fR
+is set) or by the specification of a limit with the
+\fIK\fR
+identifier in
+\fBlimits\fR(5)\&.
+.RE
+.PP
+\fBUSERDEL_CMD\fR (string)
+.RS 4
+If defined, this command is run when removing a user\&. It should remove any at/cron/print jobs etc\&. owned by the user to be removed (passed as the first argument)\&.
+.sp
+The return code of the script is not taken into account\&.
+.sp
+Here is an example script, which removes the user\*(Aqs cron, at and print jobs:
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+#! /bin/sh
+
+# Check for the required argument\&.
+if [ $# != 1 ]; then
+ echo "Usage: $0 username"
+ exit 1
+fi
+
+# Remove cron jobs\&.
+crontab \-r \-u $1
+
+# Remove at jobs\&.
+# Note that it will remove any jobs owned by the same UID,
+# even if it was shared by a different username\&.
+AT_SPOOL_DIR=/var/spool/cron/atjobs
+find $AT_SPOOL_DIR \-name "[^\&.]*" \-type f \-user $1 \-delete \e;
+
+# Remove print jobs\&.
+lprm $1
+
+# All done\&.
+exit 0
+
+.fi
+.if n \{\
+.RE
+.\}
+.sp
+.RE
+.PP
+\fBUSERGROUPS_ENAB\fR (boolean)
+.RS 4
+Enable setting of the umask group bits to be the same as owner bits (examples: 022 \-> 002, 077 \-> 007) for non\-root users, if the uid is the same as gid, and username is the same as the primary group name\&.
+.sp
+If set to
+\fIyes\fR,
+\fBuserdel\fR
+will remove the user\*(Aqs group if it contains no more members, and
+\fBuseradd\fR
+will create by default a group with the name of the user\&.
+.RE
+.SH "CROSS REFERENCES"
+.PP
+The following cross references show which programs in the shadow password suite use which parameters\&.
+.PP
+chfn
+.RS 4
+CHFN_AUTH
+CHFN_RESTRICT
+LOGIN_STRING
+.RE
+.PP
+chgpasswd
+.RS 4
+ENCRYPT_METHOD MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB
+SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
+.RE
+.PP
+chpasswd
+.RS 4
+ENCRYPT_METHOD MD5_CRYPT_ENAB
+SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
+.RE
+.PP
+chsh
+.RS 4
+CHSH_AUTH LOGIN_STRING
+.RE
+.PP
+gpasswd
+.RS 4
+ENCRYPT_METHOD MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB
+SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
+.RE
+.PP
+groupadd
+.RS 4
+GID_MAX GID_MIN MAX_MEMBERS_PER_GROUP SYS_GID_MAX SYS_GID_MIN
+.RE
+.PP
+groupdel
+.RS 4
+MAX_MEMBERS_PER_GROUP
+.RE
+.PP
+groupmems
+.RS 4
+MAX_MEMBERS_PER_GROUP
+.RE
+.PP
+groupmod
+.RS 4
+MAX_MEMBERS_PER_GROUP
+.RE
+.PP
+grpck
+.RS 4
+MAX_MEMBERS_PER_GROUP
+.RE
+.PP
+grpconv
+.RS 4
+MAX_MEMBERS_PER_GROUP
+.RE
+.PP
+grpunconv
+.RS 4
+MAX_MEMBERS_PER_GROUP
+.RE
+.PP
+lastlog
+.RS 4
+LASTLOG_UID_MAX
+.RE
+.PP
+login
+.RS 4
+CONSOLE
+CONSOLE_GROUPS DEFAULT_HOME
+ENV_HZ ENV_PATH ENV_SUPATH ENV_TZ ENVIRON_FILE
+ERASECHAR FAIL_DELAY
+FAILLOG_ENAB
+FAKE_SHELL
+FTMP_FILE
+HUSHLOGIN_FILE
+ISSUE_FILE
+KILLCHAR
+LASTLOG_ENAB LASTLOG_UID_MAX
+LOGIN_RETRIES
+LOGIN_STRING
+LOGIN_TIMEOUT LOG_OK_LOGINS LOG_UNKFAIL_ENAB
+MAIL_CHECK_ENAB MAIL_DIR MAIL_FILE MOTD_FILE NOLOGINS_FILE PORTTIME_CHECKS_ENAB QUOTAS_ENAB
+TTYGROUP TTYPERM TTYTYPE_FILE
+ULIMIT UMASK
+USERGROUPS_ENAB
+.RE
+.PP
+newgrp / sg
+.RS 4
+SYSLOG_SG_ENAB
+.RE
+.PP
+newusers
+.RS 4
+ENCRYPT_METHOD GID_MAX GID_MIN MAX_MEMBERS_PER_GROUP MD5_CRYPT_ENAB HOME_MODE PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE
+SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
+SUB_GID_COUNT SUB_GID_MAX SUB_GID_MIN SUB_UID_COUNT SUB_UID_MAX SUB_UID_MIN SYS_GID_MAX SYS_GID_MIN SYS_UID_MAX SYS_UID_MIN UID_MAX UID_MIN UMASK
+.RE
+.PP
+passwd
+.RS 4
+ENCRYPT_METHOD MD5_CRYPT_ENAB OBSCURE_CHECKS_ENAB PASS_ALWAYS_WARN PASS_CHANGE_TRIES PASS_MAX_LEN PASS_MIN_LEN
+SHA_CRYPT_MAX_ROUNDS SHA_CRYPT_MIN_ROUNDS
+.RE
+.PP
+pwck
+.RS 4
+PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE
+.RE
+.PP
+pwconv
+.RS 4
+PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE
+.RE
+.PP
+su
+.RS 4
+CONSOLE
+CONSOLE_GROUPS DEFAULT_HOME
+ENV_HZ ENVIRON_FILE
+ENV_PATH ENV_SUPATH
+ENV_TZ LOGIN_STRING MAIL_CHECK_ENAB MAIL_DIR MAIL_FILE QUOTAS_ENAB
+SULOG_FILE SU_NAME
+SU_WHEEL_ONLY
+SYSLOG_SU_ENAB
+USERGROUPS_ENAB
+.RE
+.PP
+sulogin
+.RS 4
+ENV_HZ
+ENV_TZ
+.RE
+.PP
+useradd
+.RS 4
+CREATE_HOME GID_MAX GID_MIN HOME_MODE LASTLOG_UID_MAX MAIL_DIR MAX_MEMBERS_PER_GROUP PASS_MAX_DAYS PASS_MIN_DAYS PASS_WARN_AGE SUB_GID_COUNT SUB_GID_MAX SUB_GID_MIN SUB_UID_COUNT SUB_UID_MAX SUB_UID_MIN SYS_GID_MAX SYS_GID_MIN SYS_UID_MAX SYS_UID_MIN UID_MAX UID_MIN UMASK
+.RE
+.PP
+userdel
+.RS 4
+MAIL_DIR MAIL_FILE MAX_MEMBERS_PER_GROUP USERDEL_CMD USERGROUPS_ENAB
+.RE
+.PP
+usermod
+.RS 4
+LASTLOG_UID_MAX MAIL_DIR MAIL_FILE MAX_MEMBERS_PER_GROUP
+.RE
+.SH "SEE ALSO"
+.PP
+\fBlogin\fR(1),
+\fBpasswd\fR(1),
+\fBsu\fR(1),
+\fBpasswd\fR(5),
+\fBshadow\fR(5),
+\fBpam\fR(8)\&.
diff --git a/man/man5/passwd.5 b/man/man5/passwd.5
new file mode 100644
index 0000000..c66e932
--- /dev/null
+++ b/man/man5/passwd.5
@@ -0,0 +1,193 @@
+'\" t
+.\" Title: passwd
+.\" Author: Julianne Frances Haugh
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "PASSWD" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+passwd \- the password file
+.SH "DESCRIPTION"
+.PP
+/etc/passwd
+contains one line for each user account, with seven fields delimited by colons (\(lq:\(rq)\&. These fields are:
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+login name
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+optional encrypted password
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+numerical user ID
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+numerical group ID
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+user name or comment field
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+user home directory
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+optional user command interpreter
+.RE
+.PP
+If the
+\fIpassword\fR
+field is a lower\-case
+\(lqx\(rq, then the encrypted password is actually stored in the
+\fBshadow\fR(5)
+file instead; there
+\fImust\fR
+be a corresponding line in the
+/etc/shadow
+file, or else the user account is invalid\&.
+.PP
+The encrypted
+\fIpassword\fR
+field may be empty, in which case no password is required to authenticate as the specified login name\&. However, some applications which read the
+/etc/passwd
+file may decide not to permit
+\fIany\fR
+access at all if the
+\fIpassword\fR
+field is blank\&.
+.PP
+A
+\fIpassword\fR
+field which starts with an exclamation mark means that the password is locked\&. The remaining characters on the line represent the
+\fIpassword\fR
+field before the password was locked\&.
+.PP
+Refer to
+\fBcrypt\fR(3)
+for details on how this string is interpreted\&.
+.PP
+If the password field contains some string that is not a valid result of
+\fBcrypt\fR(3), for instance ! or *, the user will not be able to use a unix password to log in (but the user may log in the system by other means)\&.
+.PP
+The comment field is used by various system utilities, such as
+\fBfinger\fR(1)\&.
+.PP
+The home directory field provides the name of the initial working directory\&. The
+\fBlogin\fR
+program uses this information to set the value of the
+\fB$HOME\fR
+environmental variable\&.
+.PP
+The command interpreter field provides the name of the user\*(Aqs command language interpreter, or the name of the initial program to execute\&. The
+\fBlogin\fR
+program uses this information to set the value of the
+\fB$SHELL\fR
+environmental variable\&. If this field is empty, it defaults to the value
+/bin/sh\&.
+.SH "FILES"
+.PP
+/etc/passwd
+.RS 4
+User account information\&.
+.RE
+.PP
+/etc/shadow
+.RS 4
+optional encrypted password file
+.RE
+.PP
+/etc/passwd\-
+.RS 4
+Backup file for /etc/passwd\&.
+.sp
+Note that this file is used by the tools of the shadow toolsuite, but not by all user and password management tools\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBcrypt\fR(3),
+\fBgetent\fR(1),
+\fBgetpwnam\fR(3),
+\fBlogin\fR(1),
+\fBpasswd\fR(1),
+\fBpwck\fR(8),
+\fBpwconv\fR(8),
+\fBpwunconv\fR(8),
+\fBshadow\fR(5),
+\fBsu\fR(1),
+\fBsulogin\fR(8)\&.
diff --git a/man/man5/porttime.5 b/man/man5/porttime.5
new file mode 100644
index 0000000..38105cf
--- /dev/null
+++ b/man/man5/porttime.5
@@ -0,0 +1,96 @@
+'\" t
+.\" Title: porttime
+.\" Author: Julianne Frances Haugh
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "PORTTIME" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+porttime \- port access time file
+.SH "DESCRIPTION"
+.PP
+\fIporttime\fR
+contains a list of tty devices, user names, and permitted login times\&.
+.PP
+Each entry consists of three colon separated fields\&. The first field is a comma separated list of tty devices, or an asterisk to indicate that all tty devices are matched by this entry\&. The second field is a comma separated list of user names, or an asterisk to indicated that all user names are matched by this entry\&. The third field is a comma separated list of permitted access times\&.
+.PP
+Each access time entry consists of zero or more days of the week, abbreviated
+\fISu\fR,
+\fIMo\fR,
+\fITu\fR,
+\fIWe\fR,
+\fITh\fR,
+\fIFr\fR, and
+\fISa\fR, followed by a pair of times separated by a hyphen\&. The abbreviation
+\fIWk\fR
+may be used to represent Monday thru Friday, and
+\fIAl\fR
+may be used to indicate every day\&. If no days are given,
+\fIAl\fR
+is assumed\&.
+.SH "EXAMPLES"
+.PP
+The following entry allows access to user
+\fBjfh\fR
+on every port during weekdays from 9am to 5pm\&.
+.PP
+*:jfh:Wk0900\-1700
+.PP
+The following entries allow access only to the users
+\fIroot\fR
+and
+\fIoper\fR
+on
+/dev/console
+at any time\&. This illustrates how the
+/etc/porttime
+file is an ordered list of access times\&. Any other user would match the second entry which does not permit access at any time\&.
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+ console:root,oper:Al0000\-2400
+ console:*:
+
+.fi
+.if n \{\
+.RE
+.\}
+.PP
+The following entry allows access for the user
+\fIgames\fR
+on any port during non\-working hours\&.
+.PP
+*:games:Wk1700\-0900,SaSu0000\-2400
+.SH "FILES"
+.PP
+/etc/porttime
+.RS 4
+File containing port access\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBlogin\fR(1)\&.
diff --git a/man/man5/shadow.5 b/man/man5/shadow.5
new file mode 100644
index 0000000..2b4a707
--- /dev/null
+++ b/man/man5/shadow.5
@@ -0,0 +1,148 @@
+'\" t
+.\" Title: shadow
+.\" Author: Julianne Frances Haugh
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "SHADOW" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+shadow \- shadowed password file
+.SH "DESCRIPTION"
+.PP
+shadow
+is a file which contains the password information for the system\*(Aqs accounts and optional aging information\&.
+.PP
+This file must not be readable by regular users if password security is to be maintained\&.
+.PP
+Each line of this file contains 9 fields, separated by colons (\(lq:\(rq), in the following order:
+.PP
+\fBlogin name\fR
+.RS 4
+It must be a valid account name, which exist on the system\&.
+.RE
+.PP
+\fBencrypted password\fR
+.RS 4
+This field may be empty, in which case no passwords are required to authenticate as the specified login name\&. However, some applications which read the
+/etc/shadow
+file may decide not to permit any access at all if the password field is empty\&.
+.sp
+A password field which starts with an exclamation mark means that the password is locked\&. The remaining characters on the line represent the password field before the password was locked\&.
+.sp
+Refer to
+\fBcrypt\fR(3)
+for details on how this string is interpreted\&.
+.sp
+If the password field contains some string that is not a valid result of
+\fBcrypt\fR(3), for instance ! or *, the user will not be able to use a unix password to log in (but the user may log in the system by other means)\&.
+.RE
+.PP
+\fBdate of last password change\fR
+.RS 4
+The date of the last password change, expressed as the number of days since Jan 1, 1970\&.
+.sp
+The value 0 has a special meaning, which is that the user should change her password the next time she will log in the system\&.
+.sp
+An empty field means that password aging features are disabled\&.
+.RE
+.PP
+\fBminimum password age\fR
+.RS 4
+The minimum password age is the number of days the user will have to wait before she will be allowed to change her password again\&.
+.sp
+An empty field and value 0 mean that there are no minimum password age\&.
+.RE
+.PP
+\fBmaximum password age\fR
+.RS 4
+The maximum password age is the number of days after which the user will have to change her password\&.
+.sp
+After this number of days is elapsed, the password may still be valid\&. The user should be asked to change her password the next time she will log in\&.
+.sp
+An empty field means that there are no maximum password age, no password warning period, and no password inactivity period (see below)\&.
+.sp
+If the maximum password age is lower than the minimum password age, the user cannot change her password\&.
+.RE
+.PP
+\fBpassword warning period\fR
+.RS 4
+The number of days before a password is going to expire (see the maximum password age above) during which the user should be warned\&.
+.sp
+An empty field and value 0 mean that there are no password warning period\&.
+.RE
+.PP
+\fBpassword inactivity period\fR
+.RS 4
+The number of days after a password has expired (see the maximum password age above) during which the password should still be accepted (and the user should update her password during the next login)\&.
+.sp
+After expiration of the password and this expiration period is elapsed, no login is possible using the current user\*(Aqs password\&. The user should contact her administrator\&.
+.sp
+An empty field means that there are no enforcement of an inactivity period\&.
+.RE
+.PP
+\fBaccount expiration date\fR
+.RS 4
+The date of expiration of the account, expressed as the number of days since Jan 1, 1970\&.
+.sp
+Note that an account expiration differs from a password expiration\&. In case of an account expiration, the user shall not be allowed to login\&. In case of a password expiration, the user is not allowed to login using her password\&.
+.sp
+An empty field means that the account will never expire\&.
+.sp
+The value 0 should not be used as it is interpreted as either an account with no expiration, or as an expiration on Jan 1, 1970\&.
+.RE
+.PP
+\fBreserved field\fR
+.RS 4
+This field is reserved for future use\&.
+.RE
+.SH "FILES"
+.PP
+/etc/passwd
+.RS 4
+User account information\&.
+.RE
+.PP
+/etc/shadow
+.RS 4
+Secure user account information\&.
+.RE
+.PP
+/etc/shadow\-
+.RS 4
+Backup file for /etc/shadow\&.
+.sp
+Note that this file is used by the tools of the shadow toolsuite, but not by all user and password management tools\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBchage\fR(1),
+\fBlogin\fR(1),
+\fBpasswd\fR(1),
+\fBpasswd\fR(5),
+\fBpwck\fR(8),
+\fBpwconv\fR(8),
+\fBpwunconv\fR(8),
+\fBsu\fR(1),
+\fBsulogin\fR(8)\&.
diff --git a/man/man5/suauth.5 b/man/man5/suauth.5
new file mode 100644
index 0000000..9b5ad03
--- /dev/null
+++ b/man/man5/suauth.5
@@ -0,0 +1,146 @@
+'\" t
+.\" Title: suauth
+.\" Author: Marek Michałkiewicz
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "SUAUTH" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+suauth \- detailed su control file
+.SH "SYNOPSIS"
+.HP \w'\fB/etc/suauth\fR\ 'u
+\fB/etc/suauth\fR
+.SH "DESCRIPTION"
+.PP
+The file
+/etc/suauth
+is referenced whenever the su command is called\&. It can change the behaviour of the su command, based upon:
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+ 1) the user su is targeting
+
+.fi
+.if n \{\
+.RE
+.\}
+.PP
+2) the user executing the su command (or any groups he might be a member of)
+.PP
+The file is formatted like this, with lines starting with a # being treated as comment lines and ignored;
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+ to\-id:from\-id:ACTION
+
+.fi
+.if n \{\
+.RE
+.\}
+.PP
+Where to\-id is either the word
+\fIALL\fR, a list of usernames delimited by "," or the words
+\fIALL EXCEPT\fR
+followed by a list of usernames delimited by ","\&.
+.PP
+from\-id is formatted the same as to\-id except the extra word
+\fIGROUP\fR
+is recognized\&.
+\fIALL EXCEPT GROUP\fR
+is perfectly valid too\&. Following
+\fIGROUP\fR
+appears one or more group names, delimited by ","\&. It is not sufficient to have primary group id of the relevant group, an entry in
+\fB/etc/group\fR(5)
+is necessary\&.
+.PP
+Action can be one only of the following currently supported options\&.
+.PP
+\fIDENY\fR
+.RS 4
+The attempt to su is stopped before a password is even asked for\&.
+.RE
+.PP
+\fINOPASS\fR
+.RS 4
+The attempt to su is automatically successful; no password is asked for\&.
+.RE
+.PP
+\fIOWNPASS\fR
+.RS 4
+For the su command to be successful, the user must enter his or her own password\&. They are told this\&.
+.RE
+.PP
+Note there are three separate fields delimited by a colon\&. No whitespace must surround this colon\&. Also note that the file is examined sequentially line by line, and the first applicable rule is used without examining the file further\&. This makes it possible for a system administrator to exercise as fine control as he or she wishes\&.
+.SH "EXAMPLE"
+.sp
+.if n \{\
+.RS 4
+.\}
+.nf
+ # sample /etc/suauth file
+ #
+ # A couple of privileged usernames may
+ # su to root with their own password\&.
+ #
+ root:chris,birddog:OWNPASS
+ #
+ # Anyone else may not su to root unless in
+ # group wheel\&. This is how BSD does things\&.
+ #
+ root:ALL EXCEPT GROUP wheel:DENY
+ #
+ # Perhaps terry and birddog are accounts
+ # owned by the same person\&.
+ # Access can be arranged between them
+ # with no password\&.
+ #
+ terry:birddog:NOPASS
+ birddog:terry:NOPASS
+ #
+
+.fi
+.if n \{\
+.RE
+.\}
+.SH "FILES"
+.PP
+/etc/suauth
+.RS 4
+.RE
+.SH "BUGS"
+.PP
+There could be plenty lurking\&. The file parser is particularly unforgiving about syntax errors, expecting no spurious whitespace (apart from beginning and end of lines), and a specific token delimiting different things\&.
+.SH "DIAGNOSTICS"
+.PP
+An error parsing the file is reported using
+\fBsyslogd\fR(8)
+as level ERR on facility AUTH\&.
+.SH "SEE ALSO"
+.PP
+\fBsu\fR(1)\&.
diff --git a/man/man5/subgid.5 b/man/man5/subgid.5
new file mode 100644
index 0000000..8db1f45
--- /dev/null
+++ b/man/man5/subgid.5
@@ -0,0 +1,100 @@
+'\" t
+.\" Title: subgid
+.\" Author: Eric Biederman
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "SUBGID" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+subgid \- the subordinate gid file
+.SH "DESCRIPTION"
+.PP
+Each line in
+/etc/subgid
+contains a user name and a range of subordinate group ids that user is allowed to use\&. This is specified with three fields delimited by colons (\(lq:\(rq)\&. These fields are:
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+login name or UID
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+numerical subordinate group ID
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+numerical subordinate group ID count
+.RE
+.PP
+This file specifies the group IDs that ordinary users can use, with the
+\fBnewgidmap\fR
+command, to configure gid mapping in a user namespace\&.
+.PP
+Multiple ranges may be specified per user\&.
+.PP
+When large number of entries (10000\-100000 or more) are defined in
+/etc/subgid, parsing performance penalty will become noticeable\&. In this case it is recommended to use UIDs instead of login names\&. Benchmarks have shown speed\-ups up to 20x\&.
+.SH "FILES"
+.PP
+/etc/subgid
+.RS 4
+Per user subordinate group IDs\&.
+.RE
+.PP
+/etc/subgid\-
+.RS 4
+Backup file for /etc/subgid\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBlogin.defs\fR(5),
+\fBnewgidmap\fR(1),
+\fBnewuidmap\fR(1),
+\fBnewusers\fR(8),
+\fBsubuid\fR(5),
+\fBuseradd\fR(8),
+\fBuserdel\fR(8),
+\fBusermod\fR(8),
+\fBuser_namespaces\fR(7)\&.
diff --git a/man/man5/subuid.5 b/man/man5/subuid.5
new file mode 100644
index 0000000..0876ecb
--- /dev/null
+++ b/man/man5/subuid.5
@@ -0,0 +1,100 @@
+'\" t
+.\" Title: subuid
+.\" Author: Eric Biederman
+.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
+.\" Date: 01/23/2020
+.\" Manual: File Formats and Conversions
+.\" Source: shadow-utils 4.8.1
+.\" Language: English
+.\"
+.TH "SUBUID" "5" "01/23/2020" "shadow\-utils 4\&.8\&.1" "File Formats and Conversions"
+.\" -----------------------------------------------------------------
+.\" * Define some portability stuff
+.\" -----------------------------------------------------------------
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.\" http://bugs.debian.org/507673
+.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
+.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\" -----------------------------------------------------------------
+.\" * set default formatting
+.\" -----------------------------------------------------------------
+.\" disable hyphenation
+.nh
+.\" disable justification (adjust text to left margin only)
+.ad l
+.\" -----------------------------------------------------------------
+.\" * MAIN CONTENT STARTS HERE *
+.\" -----------------------------------------------------------------
+.SH "NAME"
+subuid \- the subordinate uid file
+.SH "DESCRIPTION"
+.PP
+Each line in
+/etc/subuid
+contains a user name and a range of subordinate user ids that user is allowed to use\&. This is specified with three fields delimited by colons (\(lq:\(rq)\&. These fields are:
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+login name or UID
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+numerical subordinate user ID
+.RE
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+numerical subordinate user ID count
+.RE
+.PP
+This file specifies the user IDs that ordinary users can use, with the
+\fBnewuidmap\fR
+command, to configure uid mapping in a user namespace\&.
+.PP
+Multiple ranges may be specified per user\&.
+.PP
+When large number of entries (10000\-100000 or more) are defined in
+/etc/subuid, parsing performance penalty will become noticeable\&. In this case it is recommended to use UIDs instead of login names\&. Benchmarks have shown speed\-ups up to 20x\&.
+.SH "FILES"
+.PP
+/etc/subuid
+.RS 4
+Per user subordinate user IDs\&.
+.RE
+.PP
+/etc/subuid\-
+.RS 4
+Backup file for /etc/subuid\&.
+.RE
+.SH "SEE ALSO"
+.PP
+\fBlogin.defs\fR(5),
+\fBnewgidmap\fR(1),
+\fBnewuidmap\fR(1),
+\fBnewusers\fR(1),
+\fBsubgid\fR(5),
+\fBuseradd\fR(8),
+\fBuserdel\fR(8),
+\fBusermod\fR(8),
+\fBuser_namespaces\fR(7)\&.