:sig
String shell_exec(String cmd)

:params
cmd : string that contains the shell command line to be executed
return value : output of the command execution

:see
>sys

:content
Executes a Linux shell command and returns the generated output.

When command text includes user-controlled input, escape that input first with `shell_escape()`.

Related:

- PHP: `shell_exec()`, `exec()`, or `proc_open()`
- JavaScript / Node.js: Node `child_process.exec()` or `spawn()`
