man/usermod.8.xml - master - niceSOFT/shadow

man/usermod.8.xml
686 строк22 KB
Michael Vetter
man: Document UAPI merging in login.defs
10 авг 2026, 15:51
10 авг 2026, 15:51e4bd855
<?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>&nbsp;<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>&nbsp;<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>&nbsp;<replaceable>EXPIRE_DATE</replaceable>
	</term>
	<listitem>
	  <para>
	    Specifies the date on which the user account will be disabled.
	    The value can be specified as a date in the YYYY-MM-DD format
	    or as a number of days since 1970-01-01.
	    The date is interpreted using the UTC timezone.
	  </para>
	  <para>
	    An input of -1 or an empty string blanks the account expiration field
	    in the shadow password file.
	    The account will remain available with no expiration date.
	  </para>
	  <para>
	    This option requires the <filename>/etc/shadow</filename> file.
	    If no entry exists in the <filename>/etc/shadow</filename> file,
	    the system will automatically create one.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-f</option>, <option>--inactive</option>&nbsp;<replaceable>INACTIVE</replaceable>
	</term>
	<listitem>
	  <para>
	    Defines the number of days after a password exceeds its maximum age
	    during which the user can still log in by immediately changing their password.
	    If the user does not change their password within this period of time,
	    their account becomes inactive.
	    This value is stored in the shadow password file.
	  </para>
	  <para>
	    A value of 0 disables the account when the password expires, with no delay.
	    </para>
	  <para>
	    A value of -1 empties the respective field in the shadow password file,
	    which means that the inactivity period is not enforced.
	  </para>
	  <para>
	    This option requires the <filename>/etc/shadow</filename> file.
	    If no entry exist in the <filename>/etc/shadow</filename> file,
	    the system will automatically create one.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-g</option>, <option>--gid</option>&nbsp;<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>&nbsp;<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>&nbsp;<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>&nbsp;<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>&nbsp;<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.
		No SELINUX support.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-P</option>, <option>--prefix</option>&nbsp;<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>&nbsp;<replaceable>SHELL</replaceable>
	</term>
	<listitem>
	  <para>
	    changes the user's login shell. An empty string for SHELL empties 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>&nbsp;<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>&nbsp;<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>&nbsp;<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>&nbsp;<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>&nbsp;<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 condition="subids">
	<term>
	  <option>-S</option>, <option>--add-subids</option>
	</term>
	<listitem>
	  <para>
	    Add subordinate uids and gids to the user's account.
	  </para>
	  <para>
	     An appropriate uid and gid range is automatically selected from /etc/login.defs defaults.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-Z</option>, <option>--selinux-user</option>&nbsp;<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>
      <varlistentry>
	<term>
	  <option>--selinux-range</option>&nbsp;<replaceable>SERANGE</replaceable>
	</term>
	<listitem>
	  <para>
	    defines the SELinux MLS range for the new account.
	    Note that the shadow system doesn't store the selinux-range,
	    it uses <citerefentry><refentrytitle>semanage</refentrytitle>
	    <manvolnum>8</manvolnum></citerefentry> for that.
	  </para>
	  <para>
	    This option is only valid if the <option>-Z</option> (or
	    <option>--selinux-user</option>) option is specified.
	  </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 information</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <citerefentry>
	    <refentrytitle>login.defs</refentrytitle><manvolnum>5</manvolnum>
	  </citerefentry>
	</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>