What is the purpose of PHP safe mode and how does it impact the execution of shell_exec in PHP scripts?

The purpose of PHP safe mode is to enhance security by restricting the execution of certain functions and commands that could potentially pose a security risk. When safe mode is enabled, functions like shell_exec, which execute shell commands, may be disabled. To work around this limitation, you can use the PHP function escapeshellcmd to escape the shell command before passing it to shell_exec.

$command = 'ls -l';
$escaped_command = escapeshellcmd($command);
$output = shell_exec($escaped_command);
echo $output;