Start script after another one (already running) finishes

Question

So I have a process running, and it will take several hours to complete. I would like to start another process right after that one finishes, automatically. Notice that I can't add a call to the second script in the first one, neither create another which sequentially runs both. Is there any way to do this in Linux?

Edit: One option is to poll every x minutes using pgrep and check if the process finished. If it did, start the other one. However, I don't like this solution.

PS: Both are bash scripts, if that helps.

Answer 1

Given the PID of the first process, the loop

while ps -p $PID; do sleep 1; done ; script2 

should do the trick. This is a little more stable than pgrep and process names.

Answer 2

Maybe you can press ctrl+z first and enter

fg; echo "first job finished" 

Answer 3

Polling is probably the way to go, but it doesn't have to be horrible.

pid=$(ps -opid= -C your_script_name)
while [ -d /proc/$pid ] ; do
    sleep 1
done && ./your_other_script