<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<!-- splitted from ./en/functions/exec.xml, last change in rev 1.24 -->
<refentry xml:id="function.system" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>system</refname>
  <refpurpose>Execute an external program and display the output</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>string</type><methodname>system</methodname>
   <methodparam><type>string</type><parameter>command</parameter></methodparam>
   <methodparam choice="opt"><type>int</type><parameter role="reference">return_var</parameter></methodparam>
  </methodsynopsis>
  <para>
   <function>system</function> is just like the C version of the
   function in that it executes the given
   <parameter>command</parameter> and outputs the result.
  </para>
  <para>
   The <function>system</function> call also tries to automatically
   flush the web server's output buffer after each line of output if
   PHP is running as a server module.
  </para>
  <para>
   If you need to execute a command and have all the data from the
   command passed directly back without any interference, use the
   <function>passthru</function> function.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>command</parameter></term>
     <listitem>
      <para>
       The command that will be executed.
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>return_var</parameter></term>
     <listitem>
      <para>
       If the <parameter>return_var</parameter> argument is present, then the
       return status of the executed command will be written to this
       variable.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the last line of the command output on success, and &false;
   on failure.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>system</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
echo '<pre>';

// Outputs all the result of shellcommand "ls", and returns
// the last output line into $last_line. Stores the return value
// of the shell command in $retval.
$last_line = system('ls', $retval);

// Printing additional info
echo '
</pre>
<hr />Last line of the output: ' . $last_line . '
<hr />Return value: ' . $retval;
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  &warn.escapeshell;
  &note.exec-bg;
  &note.exec-path;
  &warn.sm.exec;
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>exec</function></member>
    <member><function>passthru</function></member>
    <member><function>popen</function></member>
    <member><function>escapeshellcmd</function></member>
    <member><function>pcntl_exec</function></member>
    <member><link linkend="language.operators.execution">backtick operator</link></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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