Check if any function to execute commands (REC) in PHP is available

Check-RCEcommands.php

<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

echo "Hello! Trying to execute commands...";
echo "<br>";
if (function_exists('exec')){ exec("echo exec"); echo "<br>";}
if (function_exists('passthru')){ passthru("echo passthru"); echo "<br>";}
if (function_exists('shell_exec')){ shell_exec("echo shell_exec"); echo "<br>";}
if (function_exists('popen')){ $p = popen('/bin/echo popen 2>&1', 'r'); echo fread($p, 2096); pclose($p); echo "<br>";}
if (function_exists('proc_open')) echo "proc_open<br>";
if (function_exists('pcntl_exec')) echo "pcntl_exec<br>";
`echo backtips`; echo "<br>";
?>