Escape shell metacharacters (original) (raw)

escapeshellcmd

(PHP 4, PHP 5, PHP 7)

escapeshellcmd — Escape shell metacharacters

Description

escapeshellcmd ( string $command ) : string

Following characters are preceded by a backslash:&#;`|*?~<>^()[]{}$\, \x0A and \xFF. ' and " are escaped only if they are not paired. On Windows, all these characters plus % and ! are preceded by a caret (^).

Parameters

command

The command that will be escaped.

Return Values

The escaped string.

Examples

Example #1 escapeshellcmd() example

<?php // We allow arbitrary number of arguments intentionally here. <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>c</mi><mi>o</mi><mi>m</mi><mi>m</mi><mi>a</mi><mi>n</mi><mi>d</mi><msup><mo>=</mo><mo mathvariant="normal" lspace="0em" rspace="0em">′</mo></msup><mi mathvariant="normal">.</mi><mi mathvariant="normal">/</mi><mi>c</mi><mi>o</mi><mi>n</mi><mi>f</mi><mi>i</mi><mi>g</mi><mi>u</mi><mi>r</mi><msup><mi>e</mi><mo mathvariant="normal" lspace="0em" rspace="0em">′</mo></msup><mi mathvariant="normal">.</mi></mrow><annotation encoding="application/x-tex">command = './configure '.</annotation></semantics></math>command=′./configure′._POST['configure_options'];$escaped_command = escapeshellcmd($command);system($escaped_command); ?>

Warning

escapeshellcmd() should be used on the whole command string, and it still allows the attacker to pass arbitrary number of arguments. For escaping a single argument escapeshellarg() should be used instead.

Changelog

Version	Description
5.4.43, 5.5.27, 5.6.11	Exclamation marks are replaced by spaces.
5.3.0	On Windows, the special characters are now properly escaped. Previously, they have been replaced with a space character.