What are the differences of system(), exec() and shell_exec() in PHP?
exec, php, shell, shell-exec, system
Solution
exec — Execute an external program
system — Execute an external program and display the output
shell_exec — Execute command via shell and return the complete output as a string
so if you don't need the output, I would go with exec.
Further details:
- http://php.net/manual/en/function.exec.php
- http://php.net/manual/en/function.system.php
- http://php.net/shell_exec
Problem
It is possible to run an external command by three PHP functions of ``` system(); exec(); shell_exec(); ``` but what are their differences? In spite of their specific applications, in most cases, the can be equally used. I am curious to know which is preferred one when they can be equally used. For example, for unzipping a file or compressing a folder (with tar command), which one is preferred (probably from performance point of view)? UPDATE: In another question, I found a very useful link describing different aspects for these functions. I share the link here, as other may use to better understand security issues and other aspects.