shadow/man/chgpasswd.8.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
   Copyright (c) 2006       , Tomasz Kłoczko
   Copyright (c) 2007 - 2011, Nicolas François
   All rights reserved.
  
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
   3. The name of the copyright holders or contributors may not be used to
      endorse or promote products derived from this software without
      specific prior written permission.
  
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
   HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY ENCRYPT_METHOD        SYSTEM "login.defs.d/ENCRYPT_METHOD.xml">
<!ENTITY MAX_MEMBERS_PER_GROUP SYSTEM "login.defs.d/MAX_MEMBERS_PER_GROUP.xml">
<!ENTITY MD5_CRYPT_ENAB        SYSTEM "login.defs.d/MD5_CRYPT_ENAB.xml">
<!ENTITY SHA_CRYPT_MIN_ROUNDS  SYSTEM "login.defs.d/SHA_CRYPT_MIN_ROUNDS.xml">
<!-- SHADOW-CONFIG-HERE -->
]>

<refentry id='chgpasswd.8'>
  <!-- $Id$ -->
  <refentryinfo>
    <author>
      <firstname>Thomas</firstname>
      <surname>Kłoczko</surname>
      <email>kloczek@pld.org.pl</email>
      <contrib>Creation, 2006</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>chgpasswd</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>chgpasswd</refname>
    <refpurpose>update group passwords in batch mode</refpurpose>
  </refnamediv>

  <refsynopsisdiv id='synopsis'>
    <cmdsynopsis>
      <command>chgpasswd</command>
      <arg choice='opt'>
	<replaceable>options</replaceable>
      </arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      The <command>chgpasswd</command> command reads a list of group name
      and password pairs from standard input and uses this information to
      update a set of existing groups. Each line is of the format:
    </para>
    <para>
      <emphasis remap='I'>group_name</emphasis>:<emphasis
      remap='I'>password</emphasis>
    </para>
    <para>
      By default the supplied password must be in clear-text, and is
      encrypted by <command>chgpasswd</command>.
    </para>
    <para>
      The default encryption algorithm can be defined for the system with
      the <option>ENCRYPT_METHOD</option> variable of <filename>/etc/login.defs</filename>,
      and can be overwiten with the <option>-e</option>,
      <option>-m</option>, or <option>-c</option> options.
    </para>
    <para>
      This command is intended to be used in a large system environment
      where many accounts are created at a single time.
    </para>
  </refsect1>

  <refsect1 id='options'>
    <title>OPTIONS</title>
    <para>
      The options which apply to the <command>chgpasswd</command> command
      are:
    </para>
    <variablelist remap='IP'>
      <varlistentry>
	<term><option>-c</option>, <option>--crypt-method</option></term>
	<listitem>
	  <para>Use the specified method to encrypt the passwords.</para>
	  <para condition="no_sha_crypt">
	    The available methods are DES, MD5, and NONE.
	  </para>
	  <para condition="sha_crypt">
	    The available methods are DES, MD5, NONE, and SHA256 or SHA512
	    if your libc support these methods.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-e</option>, <option>--encrypted</option></term>
	<listitem>
	  <para>Supplied passwords are in encrypted form.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-h</option>, <option>--help</option></term>
	<listitem>
	  <para>Display help message and exit.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-m</option>, <option>--md5</option></term>
	<listitem>
	  <para>
	    Use MD5 encryption instead of DES when the supplied passwords are
	    not encrypted.
	  </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.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry condition="sha_crypt">
	<term><option>-s</option>, <option>--sha-rounds</option></term>
	<listitem>
	  <para>
	    Use the specified number of rounds to encrypt the passwords.
	  </para>
	  <para>
	    The value 0 means that the system will choose the default
	    number of rounds for the crypt method (5000).
	  </para>
	  <para>
	    A minimal value of 1000 and a maximal value of 999,999,999
	    will be enforced.
	  </para>
	  <para>
	    You can only use this option with the SHA256 or SHA512
	    crypt method.
	  </para>
	  <para>
	    By default, the number of rounds is defined by the
	    SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in
	    <filename>/etc/login.defs</filename>.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='caveats'>
    <title>CAVEATS</title>
    <para>
      Remember to set permissions or umask to prevent readability of
      unencrypted files by other users.
    </para>
    <para>
      You should make sure the passwords and the encryption method respect
      the system's password policy.
    </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>
      &ENCRYPT_METHOD;
      &MAX_MEMBERS_PER_GROUP;
      &MD5_CRYPT_ENAB;
      &SHA_CRYPT_MIN_ROUNDS; <!--This also document SHA_CRYPT_MAX_ROUNDS-->
    </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/login.defs</filename></term>
	<listitem>
	  <para>Shadow password suite configuration.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>gpasswd</refentrytitle><manvolnum>1</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>groupadd</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>login.defs</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>