<!--
doc/src/sgml/ref/pg_controldata.sgml
PostgreSQL documentation
-->

<refentry id="app-pgcontroldata">
 <indexterm zone="app-pgcontroldata">
  <primary>pg_controldata</primary>
 </indexterm>

 <refmeta>
  <refentrytitle><application>pg_controldata</application></refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>pg_controldata</refname>
  <refpurpose>display control information of a <productname>PostgreSQL</productname> database cluster</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <cmdsynopsis>
   <command>pg_controldata</command>
   <arg choice="opt"><replaceable class="parameter">option</replaceable></arg>
   <arg choice="opt">
    <group choice="opt">
     <arg choice="plain"><option>-D</option></arg>
     <arg choice="plain"><option>--pgdata</option></arg>
    </group>
    <replaceable class="parameter">datadir</replaceable>
   </arg>
  </cmdsynopsis>
 </refsynopsisdiv>

 <refsect1 id="r1-app-pgcontroldata-1">
  <title>Description</title>
  <para>
   <command>pg_controldata</command> prints information initialized during
   <command>initdb</command>, such as the catalog version.
   It also shows information about write-ahead logging and checkpoint
   processing.  This information is cluster-wide, and not specific to any one
   database.
  </para>

  <para>
   This utility can only be run by the user who initialized the cluster because
   it requires read access to the data directory.
   You can specify the data directory on the command line, or use
   the environment variable <envar>PGDATA</envar>.
  </para>
 </refsect1>

 <refsect1>
  <title>Options</title>

   <para>
    <variablelist>
     <varlistentry>
      <term><option>-D <replaceable>datadir</replaceable></option></term>
      <term><option>--pgdata=<replaceable>datadir</replaceable></option></term>
      <listitem>
       <para>
        Specifies the directory where the database cluster is stored.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
       <term><option>-V</option></term>
       <term><option>--version</option></term>
       <listitem>
       <para>
        Print the <application>pg_controldata</application> version and exit.
       </para>
       </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-?</option></term>
      <term><option>--help</option></term>
       <listitem>
        <para>
         Show help about <application>pg_controldata</application> command line
         arguments, and exit.
        </para>
       </listitem>
      </varlistentry>
    </variablelist>
   </para>
 </refsect1>

 <refsect1>
  <title>Environment</title>

  <variablelist>
   <varlistentry>
    <term><envar>PGDATA</envar></term>

    <listitem>
     <para>
      Default data directory location
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>PG_COLOR</envar></term>
    <listitem>
     <para>
      Specifies whether to use color in diagnostic messages. Possible values
      are <literal>always</literal>, <literal>auto</literal> and
      <literal>never</literal>.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>
</refentry>
