Run When Done

May 20th, 2014
tech
If you want to run a command when another finishes, the shell can do that for you:
    $ long_running_process.sh && echo "runs on success"
    $ long_running_process.sh || echo "runs on failure"
    $ long_running_process.sh ;  echo "runs either way"
One common thing to do this with is email, so you get a notification:
    $ long_running_process.sh ; echo done | mail -s done jeff@jefftk.com
(This does require your server to be set up for sending mail in a way that won't get rejected, which is actually kind of tricky.)

For years, though, I've gotten annoyed at myself when after a process has been running for a while I wish I had set something else to run after it. Should I kill the process and start it over with && something_else.sh, or should I let it finish and then run something_else.sh on my own?

It turns out you don't have to choose! Shell job control can do this for you. Just background the first command, and then when you foreground it add the next command:

    $ sleep 10
    ^Z
    [1]+  Stopped                 sleep 10
    $ fg ; echo "finished, exit status is $?"
    sleep 10
(a few seconds of waiting)
    finished, exit status is 0
You can see fg substitutes for the original command, running as long as it would, and passing along the exit status so && and || still work.

Comment via: google plus, facebook, substack

Recent posts on blogs I like:

Elixir's Last Dance

On May 18th, the contra dance band Elixir had their last gig ever. The dance was packed: there were three hundred people. It was the only dance BIDA has ever done where they sold tickets. People flew from across the country just to hear Elixir play one la…

via Lily Wise's Blog Posts June 5, 2025

Body Language For Trans People

When I first came out as trans, resources for trans people were full of advice about body language.

via Thing of Things June 2, 2025

Workshop House case study

Lauren Hoffman interviewed me about Workshop House and wrote this post about a community I’m working on building in DC.

via Home April 30, 2025

more     (via openring)