переадресация на страницу 404.php
Если речь именно о компиляции, без запуска, то как-то так?
<?
$commands = [
'ls' => 'ls -la',
'basic' => '/path/to/basic param1 param2',
'java' => '/path/to/java param param',
];
if (isset($_FILES['file']) && !$_FILES['file']['error'] && isset($commands[$_POST['lang']]))
{
$comm = $commands[$_POST['lang']];
$file = $_FILES['file']['tmp_name'];
echo "<pre>";
echo `$comm $file 2>&1`;
echo "</pre>";
}
?>
<form enctype="multipart/form-data" method="POST">
<select name="lang">
<?php foreach ($commands as $key => $void):?>
<option><?=$key?></option>
<?php endforeach ?>
</select><input name="file" type="file" /><input type="submit" /></form>