shadow/man/usermod.8.xml

<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!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 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'>
  <!--  $Id$  -->
  <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 to reflect the changes that are specified on the command line.
    </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>-c</option>, <option>--comment</option>
	  <replaceable>COMMENT</replaceable>
	</term>
	<listitem>
	  <para>
	    The new value of the user's password file comment field. It 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.
	  </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>.
	  </para>
	  <para>
	    An empty <replaceable>EXPIRE_DATE</replaceable> argument will
	    disable the expiration of the account.
	  </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>
	    The number of days after a password expires until the account is
	    permanently disabled.
	  </para>
	  <para>
	    A value of 0 disables the account as soon
	    as the password has expired, and a value of -1 disables the
	    feature.
	  </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 group name or number of the user's new initial login 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>
	</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 are subject to the same
	    restrictions as the group given with the <option>-g</option>
	    option.
	  </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>
	    Move the content of the user's home directory to the new
	    location.
	  </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>
	    When used with the <option>-u</option> option, this option
	    allows to change the user ID to a non-unique value.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-p</option>, <option>--password</option>
	  <replaceable>PASSWORD</replaceable>
	</term>
	<listitem>
	  <para>
	    The encrypted password, as returned by <citerefentry>
	    <refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum>
	    </citerefentry>.
	  </para>
	  <para>
	    <emphasis role="bold">Note:</emphasis> This option is not
	    recommended 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>-s</option>, <option>--shell</option>
	  <replaceable>SHELL</replaceable>
	</term>
	<listitem>
	  <para>
	    The name of the user's new login shell. Setting this field to
	    blank causes the system to select the default login shell.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-u</option>, <option>--uid</option>
	  <replaceable>UID</replaceable>
	</term>
	<listitem>
	  <para>
	    The new numerical 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. Values between 0 and 999 are typically reserved
	    for system accounts.
	  </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>
	</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>
	  <term>
	    <option>-Z</option>, <option>--selinux-user</option>
	    <replaceable>SEUSER</replaceable>
	  </term>
	  <listitem>
	    <para>
	      The SELinux user for the user's login. The default is to leave
	      this field the blank, which causes the system to select the
	      default SELinux user.
	    </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, but only check if the user is logged in according to utmp
      on other architectures.
    </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>
      &MAIL_DIR; <!-- documents also MAIL_FILE -->
      &MAX_MEMBERS_PER_GROUP;
      &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><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>
    </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>,
      <citerefentry>
	<refentrytitle>useradd</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>userdel</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>