php-doc-en/reference/exec/functions/system.xml
Hannes Magnusson c030e2adf7 Upgrade to DocBook5:
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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@238160 c90b9560-bf6c-de11-be94-00142212c4b1
2007-06-20 22:25:43 +00:00

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XML

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.15 $ -->
<!-- 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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