Is there a way to use shell_exec without waiting for the command to complete?

I have a process intensive task that I would like to run in the background.

The user clicks on a page, the PHP script runs, and finally, based on some conditions, if required, then it has to run a shell script, E.G.:

shell_exec('php measurePerformance.php 47 844 [email protected]');

Currently I use shell_exec, but this requires the script to wait for an output. Is there any way to execute the command I want without waiting for it to complete?

How about adding.

"> /dev/null 2>/dev/null &"

shell_exec('php measurePerformance.php 47 844 [email protected] > /dev/null 2>/dev/null &');

Note this also gets rid of the stdio and stderr.

This will execute a command and disconnect from the running process. Of course, it can be any command you want. But for a test, you can create a php file with a sleep(20) command it.

exec("nohup /usr/bin/php -f sleep.php > /dev/null 2>&1 &");