Answer by Dennis for How to execute shell commands synchronously in PHP

If I'm getting you right, you're executing php scripts from inside a php script.

Normally, php waits for the execution of the exec ("php phpscript1.php"); to finish before processing the next line.

To avoid this, just redirect the output to /dev/null or a file and run it in background.

For example: exec ("php phpscript1.php >/dev/null 2>&1 &");.