<?xml version="1.0" encoding="UTF-8"?>
<!--
SPDX-FileCopyrightText: 1991 - 1994, Julianne Frances Haugh
SPDX-FileCopyrightText: 2007 - 2011, Nicolas François
SPDX-License-Identifier: BSD-3-Clause
-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY LASTLOG_UID_MAX SYSTEM "login.defs.d/LASTLOG_UID_MAX.xml">
<!ENTITY MAIL_DIR SYSTEM "login.defs.d/MAIL_DIR.xml">
<!ENTITY MAX_MEMBERS_PER_GROUP SYSTEM "login.defs.d/MAX_MEMBERS_PER_GROUP.xml">
<!ENTITY SUB_GID_COUNT SYSTEM "login.defs.d/SUB_GID_COUNT.xml">
<!ENTITY SUB_UID_COUNT SYSTEM "login.defs.d/SUB_UID_COUNT.xml">
<!ENTITY TCB_SYMLINKS SYSTEM "login.defs.d/TCB_SYMLINKS.xml">
<!ENTITY USE_TCB SYSTEM "login.defs.d/USE_TCB.xml">
<!-- SHADOW-CONFIG-HERE -->
]>
<refentry id='usermod.8'>
<!-- $Id$ -->
<refentryinfo>
<author>
<firstname>Julianne Frances</firstname>
<surname>Haugh</surname>
<contrib>Creation, 1991</contrib>
</author>
<author>
<firstname>Thomas</firstname>
<surname>Kłoczko</surname>
<email>kloczek@pld.org.pl</email>
<contrib>shadow-utils maintainer, 2000 - 2007</contrib>
</author>
<author>
<firstname>Nicolas</firstname>
<surname>François</surname>
<email>nicolas.francois@centraliens.net</email>
<contrib>shadow-utils maintainer, 2007 - now</contrib>
</author>
</refentryinfo>
<refmeta>
<refentrytitle>usermod</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class="sectdesc">System Management Commands</refmiscinfo>
<refmiscinfo class="source">shadow-utils</refmiscinfo>
<refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
</refmeta>
<refnamediv id='name'>
<refname>usermod</refname>
<refpurpose>modify a user account</refpurpose>
</refnamediv>
<refsynopsisdiv id='synopsis'>
<cmdsynopsis>
<command>usermod</command>
<arg choice='opt'>
<replaceable>options</replaceable>
</arg>
<arg choice='plain'><replaceable>LOGIN</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id='description'>
<title>DESCRIPTION</title>
<para>
The <command>usermod</command> command modifies the system account
files.
</para>
</refsect1>
<refsect1 id='options'>
<title>OPTIONS</title>
<para>
The options which apply to the <command>usermod</command> command
are:
</para>
<variablelist>
<varlistentry>
<term>
<option>-a</option>, <option>--append</option>
</term>
<listitem>
<para>
Add the user to the supplementary group(s). Use only with the
<option>-G</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-b</option>, <option>--badname</option>
</term>
<listitem>
<para>
Allow names that do not conform to standards.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-c</option>, <option>--comment</option> <replaceable>COMMENT</replaceable>
</term>
<listitem>
<para>
update the comment field of the user in <filename>/etc/passwd
</filename>, which is normally modified using the <citerefentry>
<refentrytitle>chfn</refentrytitle><manvolnum>1</manvolnum>
</citerefentry> utility.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-d</option>, <option>--home</option> <replaceable>HOME_DIR</replaceable>
</term>
<listitem>
<para>
The user's new login directory.
</para>
<para>
If the <option>-m</option>
option is given, the contents of the current home directory will
be moved to the new home directory, which is created if it does
not already exist. If the current home directory does not exist
the new home directory will not be created.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-e</option>, <option>--expiredate</option> <replaceable>EXPIRE_DATE</replaceable>
</term>
<listitem>
<para>
The date on which the user account will be disabled. The
date is specified in the format
<emphasis remap="I">YYYY-MM-DD</emphasis>. Integers as input are
interpreted as days after 1970-01-01.
</para>
<para>
An input of -1 or an empty string will blank the account
expiration field in the shadow password file. The account
will remain available with no date limit.
</para>
<para>
This option requires a <filename>/etc/shadow</filename> file.
A <filename>/etc/shadow</filename> entry will be created if
there were none.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-f</option>, <option>--inactive</option> <replaceable>INACTIVE</replaceable>
</term>
<listitem>
<para>
defines the number of days after the password exceeded its maximum
age during which the user may still login by immediately replacing
the password. This grace period before the account becomes inactive
is stored in the shadow password file. An input of 0 will disable an
expired password with no delay. An input of -1 will blank the
respective field in the shadow password file. See <citerefentry>
<refentrytitle>shadow</refentrytitle><manvolnum>5</manvolnum>
</citerefentry> for more information.
</para>
<para>
This option requires a <filename>/etc/shadow</filename> file.
A <filename>/etc/shadow</filename> entry will be created if
there were none.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-g</option>, <option>--gid</option> <replaceable>GROUP</replaceable>
</term>
<listitem>
<para>
The name or numerical ID of the user's new primary group.
The group must exist.
</para>
<para>
Any file from the user's home directory owned by the previous
primary group of the user will be owned by this new group.
</para>
<para>
The group ownership of files outside of the user's home directory
must be fixed manually.
</para>
<para>
The change of the group ownership of files inside of the user's
home directory is also not done if the home dir owner uid is
different from the current or new user id. This is a safety measure
for special home directories such as <filename>/</filename>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-G</option>, <option>--groups</option> <replaceable>GROUP1</replaceable>[<emphasis remap='I'>,GROUP2,...</emphasis>[<emphasis remap='I'>,GROUPN</emphasis>]]]
</term>
<listitem>
<para>
A list of supplementary groups which the user is also a member
of. Each group is separated from the next by a comma, with no
intervening whitespace. The groups must exist.
</para>
<para>
If the user is currently a member of a group which is
not listed, the user will be removed from the group. This
behaviour can be changed via the <option>-a</option> option, which
appends the user to the current supplementary group list.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-l</option>, <option>--login</option> <replaceable>NEW_LOGIN</replaceable>
</term>
<listitem>
<para>
The name of the user will be changed from
<replaceable>LOGIN</replaceable> to
<replaceable>NEW_LOGIN</replaceable>. Nothing else is changed. In
particular, the user's home directory or mail spool should
probably be renamed manually to reflect the new login name.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-L</option>, <option>--lock</option>
</term>
<listitem>
<para>
Lock a user's password. This puts a '!' in front of the
encrypted password, effectively disabling the password. You
can't use this option with <option>-p</option> or
<option>-U</option>.
</para>
<para>
Note: if you wish to lock the account (not only access with a
password), you should also set the
<replaceable>EXPIRE_DATE</replaceable> to
<replaceable>1</replaceable>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-m</option>, <option>--move-home</option>
</term>
<listitem>
<para>
moves the content of the user's home directory to the new
location. If the current home directory does not exist
the new home directory will not be created.
</para>
<para>
This option is only valid in combination with the
<option>-d</option> (or <option>--home</option>) option.
</para>
<para>
<command>usermod</command> will try to adapt the ownership of the
files and to copy the modes, ACL and extended attributes, but
manual changes might be needed afterwards.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-o</option>, <option>--non-unique</option>
</term>
<listitem>
<para>
allows to change the user ID to a non-unique value.
</para>
<para>
This option is only valid in combination with the
<option>-u</option> option. As a user identity
serves as
key to map between users on one hand and permissions, file
ownerships and other aspects that determine the system's
behavior on the other hand, more than one login name
will access the account of the given UID.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-p</option>, <option>--password</option> <replaceable>PASSWORD</replaceable>
</term>
<listitem>
<para>
defines a new password for the user. PASSWORD is expected to
be encrypted, as returned by <citerefentry><refentrytitle>crypt
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
<para>
<emphasis role="bold">Note:</emphasis> Avoid this option on the
command line because the password (or encrypted password) will
be visible by users listing the processes.
</para>
<para condition="pam">
The password will be written in the local
<filename>/etc/passwd</filename> or
<filename>/etc/shadow</filename> file. This might differ from the
password database configured in your PAM configuration.
</para>
<para>
You should make sure the password respects the system's
password policy.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-r</option>, <option>--remove</option>
</term>
<listitem>
<para>
Remove the user from named supplementary group(s). Use only with the
<option>-G</option> option.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-R</option>, <option>--root</option> <replaceable>CHROOT_DIR</replaceable>
</term>
<listitem>
<para>
Apply changes in the <replaceable>CHROOT_DIR</replaceable>
directory and use the configuration files from the
<replaceable>CHROOT_DIR</replaceable> directory.
Only absolute paths are supported.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-P</option>, <option>--prefix</option> <replaceable>PREFIX_DIR</replaceable>
</term>
<listitem>
<para>
Apply changes within the directory tree starting with
<replaceable>PREFIX_DIR</replaceable> and use as well the
configuration files located there. This option does not
chroot and is intended for preparing a cross-compilation
target. Some limitations: NIS and LDAP users/groups are
not verified. PAM authentication is using the host
files. No SELINUX support.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-s</option>, <option>--shell</option> <replaceable>SHELL</replaceable>
</term>
<listitem>
<para>
changes the user's login shell. An empty string for SHELL blanks the
field in <filename>/etc/passwd</filename> and logs the user into the
system's default shell.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-u</option>, <option>--uid</option> <replaceable>UID</replaceable>
</term>
<listitem>
<para>
The new value of the user's ID.
</para>
<para>
This value must be unique,
unless the <option>-o</option> option is used. The value must be
non-negative.
</para>
<para>
The user's mailbox, and any files which the user owns and which are
located in the user's home
directory will have the file user ID changed automatically.
</para>
<para>
The ownership of files outside of the user's home directory
must be fixed manually.
</para>
<para>
The change of the user ownership of files inside of the user's
home directory is also not done if the home dir owner uid is
different from the current or new user id. This is a safety measure
for special home directories such as <filename>/</filename>.
</para>
<para>
No checks will be performed with regard to the
<option>UID_MIN</option>, <option>UID_MAX</option>,
<option>SYS_UID_MIN</option>, or <option>SYS_UID_MAX</option>
from <filename>/etc/login.defs</filename>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-U</option>, <option>--unlock</option>
</term>
<listitem>
<para>
Unlock a user's password. This removes the '!' in front of the
encrypted password. You can't use this option with
<option>-p</option> or <option>-L</option>.
</para>
<para>
Note: if you wish to unlock the account (not only access with a
password), you should also set the
<replaceable>EXPIRE_DATE</replaceable> (for example to
<replaceable>99999</replaceable>, or to the
<option>EXPIRE</option> value from
<filename>/etc/default/useradd</filename>).
</para>
</listitem>
</varlistentry>
<varlistentry condition="subids">
<term>
<option>-v</option>, <option>--add-subuids</option> <replaceable>FIRST</replaceable>-<replaceable>LAST</replaceable>
</term>
<listitem>
<para>
Add a range of subordinate uids to the user's account.
</para>
<para>
This option may be specified multiple times to add multiple ranges to a user's account.
</para>
<para>
No checks will be performed with regard to
<option>SUB_UID_MIN</option>, <option>SUB_UID_MAX</option>, or
<option>SUB_UID_COUNT</option> from /etc/login.defs.
</para>
</listitem>
</varlistentry>
<varlistentry condition="subids">
<term>
<option>-V</option>, <option>--del-subuids</option> <replaceable>FIRST</replaceable>-<replaceable>LAST</replaceable>
</term>
<listitem>
<para>
Remove a range of subordinate uids from the user's account.
</para>
<para>
This option may be specified multiple times to remove multiple ranges to a user's account.
When both <option>--del-subuids</option> and <option>--add-subuids</option> are specified,
the removal of all subordinate uid ranges happens before any subordinate uid range is added.
</para>
<para>
No checks will be performed with regard to
<option>SUB_UID_MIN</option>, <option>SUB_UID_MAX</option>, or
<option>SUB_UID_COUNT</option> from /etc/login.defs.
</para>
</listitem>
</varlistentry>
<varlistentry condition="subids">
<term>
<option>-w</option>, <option>--add-subgids</option> <replaceable>FIRST</replaceable>-<replaceable>LAST</replaceable>
</term>
<listitem>
<para>
Add a range of subordinate gids to the user's account.
</para>
<para>
This option may be specified multiple times to add multiple ranges to a user's account.
</para>
<para>
No checks will be performed with regard to
<option>SUB_GID_MIN</option>, <option>SUB_GID_MAX</option>, or
<option>SUB_GID_COUNT</option> from /etc/login.defs.
</para>
</listitem>
</varlistentry>
<varlistentry condition="subids">
<term>
<option>-W</option>, <option>--del-subgids</option> <replaceable>FIRST</replaceable>-<replaceable>LAST</replaceable>
</term>
<listitem>
<para>
Remove a range of subordinate gids from the user's account.
</para>
<para>
This option may be specified multiple times to remove multiple ranges to a user's account.
When both <option>--del-subgids</option> and <option>--add-subgids</option> are specified,
the removal of all subordinate gid ranges happens before any subordinate gid range is added.
</para>
<para>
No checks will be performed with regard to
<option>SUB_GID_MIN</option>, <option>SUB_GID_MAX</option>, or
<option>SUB_GID_COUNT</option> from /etc/login.defs.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-Z</option>, <option>--selinux-user</option> <replaceable>SEUSER</replaceable>
</term>
<listitem>
<para>
defines the SELinux user to be mapped with
<replaceable>LOGIN</replaceable>. An empty string ("")
will remove the respective entry (if any). Note that the
shadow system doesn't store the selinux-user, it uses
semanage(8) for that.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='caveats'>
<title>CAVEATS</title>
<para>
You must make certain that the named user is
not executing any processes when this command is being executed if the
user's numerical user ID, the user's name, or the user's home
directory is being changed. <command>usermod</command> checks this
on Linux. On other operating systems it only uses utmp to check if
the user is logged in.
</para>
<para>
You must change the owner of any <command>crontab</command> files or
<command>at</command> jobs manually.
</para>
<para>
You must make any changes involving NIS on the NIS server.
</para>
</refsect1>
<refsect1 id='configuration'>
<title>CONFIGURATION</title>
<para>
The following configuration variables in
<filename>/etc/login.defs</filename> change the behavior of this
tool:
</para>
<variablelist>
&LASTLOG_UID_MAX;
&MAIL_DIR; <!-- documents also MAIL_FILE -->
&MAX_MEMBERS_PER_GROUP;
&SUB_GID_COUNT; <!-- documents also SUB_GID_MAX and SUB_GID_MIN -->
&SUB_UID_COUNT; <!-- documents also SUB_UID_MAX and SUB_UID_MIN -->
&TCB_SYMLINKS;
&USE_TCB;
</variablelist>
</refsect1>
<refsect1 id='files'>
<title>FILES</title>
<variablelist>
<varlistentry>
<term><filename>/etc/group</filename></term>
<listitem>
<para>Group account information</para>
</listitem>
</varlistentry>
<varlistentry condition="gshadow">
<term><filename>/etc/gshadow</filename></term>
<listitem>
<para>Secure group account informatio.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/login.defs</filename></term>
<listitem>
<para>Shadow password suite configuration</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/passwd</filename></term>
<listitem>
<para>User account information</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/shadow</filename></term>
<listitem>
<para>Secure user account information</para>
</listitem>
</varlistentry>
<varlistentry condition="subids">
<term><filename>/etc/subgid</filename></term>
<listitem>
<para>Per user subordinate group IDs</para>
</listitem>
</varlistentry>
<varlistentry condition="subids">
<term><filename>/etc/subuid</filename></term>
<listitem>
<para>Per user subordinate user IDs</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='see_also'>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>chfn</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>chsh</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>passwd</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>gpasswd</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>groupadd</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>groupdel</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>groupmod</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>login.defs</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<phrase condition="subids">
<citerefentry>
<refentrytitle>subgid</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>subuid</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
</phrase>
<citerefentry>
<refentrytitle>useradd</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>userdel</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>.
</para>
</refsect1>
</refentry>