<?xml version="1.0" encoding="UTF-8"?>
<!--
   SPDX-FileCopyrightText: 1992 - 1993, 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 MAX_MEMBERS_PER_GROUP SYSTEM "login.defs.d/MAX_MEMBERS_PER_GROUP.xml">
<!-- SHADOW-CONFIG-HERE -->
]>
<refentry id='grpck.8'>
  <refentryinfo>
    <author>
      <firstname>Julianne Frances</firstname>
      <surname>Haugh</surname>
      <contrib>Creation, 1992</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>grpck</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>grpck</refname>
    <refpurpose>verify integrity of group files</refpurpose>
  </refnamediv>

  <refsynopsisdiv id='synopsis'>
    <cmdsynopsis>
      <command>grpck</command>
      <arg choice='opt'>options</arg>
      <arg choice='opt'>
	<arg choice='plain'><replaceable>group</replaceable></arg>
	<arg choice='opt' condition="gshadow">
	  <arg choice='plain'><replaceable>shadow</replaceable></arg>
	</arg>
      </arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      The <command>grpck</command> command verifies the integrity of the
      groups information. It checks that all entries in
      <filename>/etc/group</filename> <phrase condition="gshadow">and
      <filename>/etc/gshadow</filename></phrase>
      have the proper format and contain valid data.
      The user is prompted to delete entries that are
      improperly formatted or which have other uncorrectable errors.
    </para>

    <para>Checks are made to verify that each entry has:</para>

    <itemizedlist mark='bullet'>
      <listitem>
	<para>the correct number of fields</para>
      </listitem>
      <listitem>
	<para>a unique and valid group name</para>
      </listitem>
      <listitem>
	<para>
	  a valid group identifier
	  <phrase condition="gshadow"> (<filename>/etc/group</filename>
	  only)</phrase>
	</para>
      </listitem>
      <listitem>
	<para>
	  a valid list of members
	  <phrase condition="gshadow"> and administrators</phrase>
	</para>
      </listitem>
      <listitem condition="gshadow">
	<para>
	  a corresponding entry in the <filename>/etc/gshadow</filename>
	  file (respectively <filename>/etc/group</filename> for the
	  <filename>gshadow</filename> checks)
	</para>
      </listitem>
    </itemizedlist>

    <para>
      The checks for correct number of fields and unique group name are
      fatal. If an entry has the wrong number of fields, the user will be
      prompted to delete the entire line. If the user does not answer
      affirmatively, all further checks are bypassed. An entry with a
      duplicated group name is prompted for deletion, but the remaining
      checks will still be made. All other errors are warnings and the user
      is encouraged to run the <command>groupmod</command> command to
      correct the error.
    </para>

    <para>
      The commands which operate on the <filename>/etc/group</filename>
      <phrase condition="no_gshadow">file</phrase><phrase
      condition="gshadow">and <filename>/etc/gshadow</filename> files</phrase>
      are not able to alter corrupted or duplicated entries. 
      <command>grpck</command> should be used in those circumstances to
      remove the offending entries.
    </para>
  </refsect1>

  <refsect1 id='options'>
    <title>OPTIONS</title>
    <para>
      The <option>-r</option> and <option>-s</option> options cannot be
      combined.
    </para>
    <para>
      The options which apply to the <command>grpck</command> command are:
    </para>
    <variablelist remap='IP'>
      <varlistentry>
	<term><option>-h</option>, <option>--help</option></term>
	<listitem>
	  <para>Display help message and exit.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-r</option>, <option>--read-only</option></term>
	<listitem>
	  <para>
	    Execute the <command>grpck</command> command in read-only mode.
	    This causes all questions regarding changes to be answered
	    <emphasis>no</emphasis> without user intervention.
	  </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>
	<term><option>-s</option>, <option>--sort</option></term>
	<listitem>
	  <para>
	    Sort entries in <filename>/etc/group</filename>
	    <phrase condition="gshadow">and
	    <filename>/etc/gshadow</filename></phrase>
	    by GID.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-S</option>, <option>--silence-warnings</option></term>
        <listitem>
          <para>
            Suppress more controversial warnings, in particular warnings about
            inconsistency between group members listed in
            <filename>/etc/group</filename> and
            <filename>/etc/ghadow</filename>.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
    <para>
      By default, <command>grpck</command> operates on
      <filename>/etc/group</filename> <phrase condition="gshadow">and
      <filename>/etc/gshadow</filename></phrase>.
      The user may select alternate files with the <emphasis
      remap='I'>group</emphasis>
      <phrase condition="no_gshadow">parameter.</phrase>
      <phrase condition="gshadow">and <emphasis remap='I'>shadow</emphasis>
      parameters.</phrase>
    </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>
      &MAX_MEMBERS_PER_GROUP;
    </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>
    </variablelist>
  </refsect1>

  <refsect1 id='exit_values'>
    <title>EXIT VALUES</title>
    <para>
      The <command>grpck</command> command exits with the following values:
      <variablelist>
	<varlistentry>
	  <term><replaceable>0</replaceable></term>
	  <listitem>
	    <para>success</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>1</replaceable></term>
	  <listitem>
	    <para>invalid command syntax</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>2</replaceable></term>
	  <listitem>
	    <para>one or more bad group entries</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>3</replaceable></term>
	  <listitem>
	    <para>can't open group files</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>4</replaceable></term>
	  <listitem>
	    <para>can't lock group files</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>5</replaceable></term>
	  <listitem>
	    <para>can't update group files</para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </para>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>group</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>groupmod</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <phrase condition="gshadow">
	<citerefentry>
	  <refentrytitle>gshadow</refentrytitle><manvolnum>5</manvolnum>,
	</citerefentry>,
      </phrase>
      <citerefentry>
	<refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>pwck</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>shadow</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>
