Escape shell metacharacters

escapeshellarg
exec
Program execution Functions
PHP Manual

# escapeshellcmd

(PHP 4, PHP 5)

escapeshellcmd — Escape shell metacharacters

### Description

string escapeshellcmd ( string `$command` )

escapeshellcmd() escapes any characters in a string that might be used to trick a shell command into executing arbitrary commands. This function should be used to make sure that any data coming from user input is escaped before this data is passed to the exec() or system() functions, or to the backtick operator.

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

### Parameters

`command`

  The command that will be escaped.

### Return Values

The escaped string.

### Examples

Example #1 escapeshellcmd() example

`<?php
$e = escapeshellcmd($userinput);
// here we don't care if $e has spaces
system("echo $e");
$f = escapeshellcmd($filename);
// and here we do, so we use quotes
system("touch \"/tmp/$f\"; ls -l \"/tmp/$f\"");
?>`

### See Also

- escapeshellarg() - Escape a string to be used as a shell argument
- exec() - Execute an external program
- popen() - Opens process file pointer
- system() - Execute an external program and display the output
- backtick operator

escapeshellarg
exec
Program execution Functions
PHP Manual