How to check if a shell command exists from PHP

Question

I need something like this in php:

If (!command_exists(\'makemiracle\')) {
  print \'no miracles\';
  return FALSE;
}
else {
  // safely call the command kno         


        

Answer 1

No, there are not.

Even when having direct access to a shell, you do not know if a command exists. There a some tricks like wheris or find / -name yourcommand but that not a 100% guarantee that you can execute the command.