Q:

Do not wait for a respondse of PHP shell_exec

Is it possible to skip waiting for a response of a shell execution command?
The command executes aria2c and places a file to the download queue. Therefore I do not have to wait for the response. Otherwise I run into a "Internal Server Error" because of max execution time is reached.

A:

you should use exec() and redirect the output to a file or null it will then run in the back ground

If a program is started with this function, in order for it to
  continue running in the background, the output of the program must be
  redirected to a file or another output stream. Failing to do so will
  cause PHP to hang until the execution of the program ends.

