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

Recent posts on blogs I like:

A Big Problem With The Going To Bed Book

One day my dad was reading this book called the "Going to Bed Book" to my sister Nora. The book is basically about a bunch of animals who are getting ready for bed on a boat. They go down the stairs, take a bath, hang their towels on the wall, find…

via Lily Wise's Blog Posts September 18, 2023

Investing in boundaries with young kids

Putting in some work to get the behavior you want The post Investing in boundaries with young kids appeared first on Otherwise.

via Otherwise August 15, 2023

Self-driving car bets

This month I lost a bunch of bets. Back in early 2016 I bet at even odds that self-driving ride sharing would be available in 10 US cities by July 2023. Then I made similar bets a dozen times because everyone disagreed with me. The first deployment to pot…

via The sideways view July 29, 2023

more     (via openring)