- is_callable: documentation ( source)
- file_exists: documentation ( source)
<?php
if ( file_exists("/etc/hosts") ){
echo "This is a linux system\n";
if(is_callable("system")){ echo "System is available\n";
}elseif(is_callable(shell_exec)){ echo "Shell_exec is available\n";
}elseif(is_callable("exec")){ echo "exec is available\n";
}else{ echo "No dice:(";}
}else{
echo "blah!\n\n";
}
?>