Question

I’m not sure what the & after the command in this bash script is doing.

    python alt_pg ${args} &

Also the original version of the script that I’m modifying does not use ‘python’ at the start of the command is that something to do with the ‘&’?

Answer 1

No, they’re two separate things.

Running python alt_pg ... means python will be looked up in $PATH, and alt_pg ... will be passed as arguments to python. Python then looks for a file named alt_pg. Running alt_pg ... means alt_pg will be looked up in $PATH. The latter may cause python to run anyway, depending on what alt_pg does.

Adding a & after the command means the command runs in the background, and the shell can continue with commands that follow even when alt_pg is still running.