shadow/man/gpasswd.1.xml

<?xml version="1.0" encoding="UTF-8"?>
<!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">
]>

<refentry id='gpasswd.1'>
  <!-- $Id$ -->
  <refmeta>
    <refentrytitle>gpasswd</refentrytitle>
    <manvolnum>1</manvolnum>
    <refmiscinfo class="sectdesc">User Commands</refmiscinfo>
  </refmeta>
  <refnamediv id='name'>
    <refname>gpasswd</refname>
    <refpurpose>
      administer the <filename>/etc/group</filename>
      <phrase condition="gshadow">and <filename>/etc/gshadow</filename>
      files</phrase>
      <phrase condition="no_gshadow">file</phrase>
    </refpurpose>
  </refnamediv>
  <!-- body begins here -->
  <refsynopsisdiv id='synopsis'>
    <cmdsynopsis>
      <command>gpasswd</command>
      <arg choice='opt'>
	<replaceable>option</replaceable>
      </arg>
      <arg choice='plain'>
	<replaceable>group</replaceable>
      </arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      The <command>gpasswd</command> command is used to administer
      <filename>/etc/group</filename><phrase condition="gshadow">,
      and <filename>/etc/gshadow</filename></phrase>.
      Every group can have
      <phrase condition="gshadow">administrators,</phrase>
      members and a password.
    </para>
    <para condition="gshadow">
      System administrator can use the <option>-A</option> option to define
      group administrator(s) and the <option>-M</option> option to define
      members and has all rights of group administrators and members.
    </para>
    <para>
      <command>gpasswd</command> called by
      <phrase condition="gshadow">a group administrator</phrase>
      <phrase condition="no_gshadow">a system administrator</phrase>
      with a group name only prompts for the new password of the
      <replaceable>group</replaceable>.
    </para>
    <para>
      If a password is set the members can still <citerefentry>
      <refentrytitle>newgrp</refentrytitle><manvolnum>1</manvolnum>
      </citerefentry> without a password, and non-members must supply the
      password.
    </para>

    <refsect2 id='notes_about_group_passwords'>
      <title>Notes about group passwords</title>
      <para>
	Group passwords are an inherent security problem since more than one
	person is permitted to know the password. However, groups are a
	useful tool for permitting co-operation between different users.
      </para>
    </refsect2>

  </refsect1>

  <refsect1 id='options'>
    <title>OPTIONS</title>
    <para condition="gshadow">
      Except for the <option>-A</option> and <option>-M</option> options,
      the options cannot be combined.
    </para>
    <para condition="no_gshadow">
      The options cannot be combined.
    </para>
    <para>
      The options which apply to the <command>gpasswd</command> command are:
    </para>
    <variablelist remap='IP'>
      <varlistentry>
	<term>
	  <option>-a</option> <replaceable>user</replaceable>
	</term>
	<listitem>
	  <para>
	    Add the <replaceable>user</replaceable> to the named
	    <replaceable>group</replaceable>.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
    <variablelist remap='IP'>
      <varlistentry>
	<term>
	  <option>-d</option> <replaceable>user</replaceable>
	</term>
	<listitem>
	  <para>
	    Remove the <replaceable>user</replaceable> from the named
	    <replaceable>group</replaceable>.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
    <variablelist remap='IP'>
      <varlistentry>
	<term>
	  <option>-r</option>
	</term>
	<listitem>
	  <para>
	    Remove the password from the named <replaceable>group</replaceable>.
	    Only group members will be allowed to use
	    <command>newgrp</command> to join the named
	    <replaceable>group</replaceable>.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
    <variablelist remap='IP'>
      <varlistentry>
	<term>
	  <option>-R</option>
	</term>
	<listitem>
	  <para>
	    Restrict the access to the named <replaceable>group</replaceable>.
	    Only group members will be allowed to use
	    <command>newgrp</command> to join the named
	    <replaceable>group</replaceable>.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
    <variablelist remap='IP' condition="gshadow">
      <varlistentry>
	<term>
	  <option>-A</option> <replaceable>user</replaceable>,...
	</term>
	<listitem>
	  <para>
	    Set the list of administrative users.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
    <variablelist remap='IP'>
      <varlistentry>
	<term>
	  <option>-M</option> <replaceable>user</replaceable>,...
	</term>
	<listitem>
	  <para>
	    Set the list of group members.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='caveats'>
    <title>CAVEATS</title>
    <para>
      This tool only operates on the <filename>/etc/group</filename>
      <phrase condition="gshadow"> and <filename>/etc/gshadow</filename>
      files.</phrase>
      <phrase condition="no_gshadow">file.</phrase>
      Thus you cannot change any NIS or LDAP group. This must be performed
      on the corresponding 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>
      &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>
    </variablelist>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>newgrp</refentrytitle><manvolnum>1</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>grpck</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>group</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry><phrase condition="gshadow">,
      <citerefentry>
	<refentrytitle>gshadow</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry></phrase>.
    </para>
  </refsect1>
</refentry>