mirror of
https://github.com/sigmasternchen/php-doc-en
synced 2025-03-20 02:48:56 +00:00
92e1c9f103
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@147556 c90b9560-bf6c-de11-be94-00142212c4b1
115 lines
3.8 KiB
XML
115 lines
3.8 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
|
|
<!-- $Revision: 1.6 $ -->
|
|
<!-- splitted from ./en/functions/exec.xml, last change in rev 1.24 -->
|
|
<refentry id="function.system">
|
|
<refnamediv>
|
|
<refname>system</refname>
|
|
<refpurpose>Execute an external program and display the output</refpurpose>
|
|
</refnamediv>
|
|
<refsect1>
|
|
<title>Description</title>
|
|
<methodsynopsis>
|
|
<type>string</type><methodname>system</methodname>
|
|
<methodparam><type>string</type><parameter>command</parameter></methodparam>
|
|
<methodparam choice="opt"><type>int</type><parameter>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. If a
|
|
variable is provided as the second argument, then the return
|
|
status code of the executed command will be written to this
|
|
variable.
|
|
</para>
|
|
<warning>
|
|
<para>
|
|
If you are going to allow data coming from user input to be passed to
|
|
this function, then you should be using
|
|
<function>escapeshellarg</function> or
|
|
<function>escapeshellcmd</function> to make sure that users cannot trick
|
|
the system into executing arbitrary commands.
|
|
</para>
|
|
</warning>
|
|
<note>
|
|
<para>
|
|
If you start a program using this function and want to leave it running
|
|
in the background, you have to make sure that the output of that program
|
|
is redirected to a file or some other output stream or else PHP will
|
|
hang until the execution of the program ends.
|
|
</para>
|
|
</note>
|
|
<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>
|
|
Returns the last line of the command output on success, and &false;
|
|
on failure.
|
|
</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>
|
|
<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>
|
|
<note>
|
|
<simpara>
|
|
When <link linkend="features.safe-mode">safe mode</link> is enabled, you
|
|
can only execute executables within the <link
|
|
linkend="ini.safe-mode-exec-dir">safe_mode_exec_dir</link>. For
|
|
practical reasons it's currently not allowed to have
|
|
<literal>..</literal> components in the path to the executable.
|
|
</simpara>
|
|
</note>
|
|
<para>
|
|
See also <function>exec</function>,
|
|
<function>passthru</function>, <function>popen</function>,
|
|
<function>escapeshellcmd</function>, and the <link
|
|
linkend="language.operators.execution">backtick operator</link>.
|
|
</para>
|
|
</refsect1>
|
|
</refentry>
|
|
|
|
<!-- Keep this comment at the end of the file
|
|
Local variables:
|
|
mode: sgml
|
|
sgml-omittag:t
|
|
sgml-shorttag:t
|
|
sgml-minimize-attributes:nil
|
|
sgml-always-quote-attributes:t
|
|
sgml-indent-step:1
|
|
sgml-indent-data:t
|
|
indent-tabs-mode:nil
|
|
sgml-parent-document:nil
|
|
sgml-default-dtd-file:"../../../../manual.ced"
|
|
sgml-exposed-tags:nil
|
|
sgml-local-catalogs:nil
|
|
sgml-local-ecat-files:nil
|
|
End:
|
|
vim600: syn=xml fen fdm=syntax fdl=2 si
|
|
vim: et tw=78 syn=sgml
|
|
vi: ts=1 sw=1
|
|
-->
|