CODEWITHSUNDEEP
bashprocess
Yotam
Yotam

Reputation: 10495

Waiting for a process to end

I would like to run n processes (in my case simulations) simultaneously, so I'm using & like so:

for i in {1..50};
do
     run simulation &
done

After each simulation is done I need to parse its output files. My question is how do I know when a process is done, and what do I do to invoke a function upon finishing a process?

EDIT: I think what I need to do is call a function that would invoke the simulation and parse its files after it is done. The way I see it this function has to be a child process anyway, right?

Thanks!

Upvotes: 0

Views: 139

Answers (3)

jfg956
jfg956

Reputation: 16758

The wait builtin waits for all child to finish. If you want to execute a command for each jobs that finishes, you can use trap. In your case, a combination of wait and trap should work:

trap parse_output SIGCHLD
for i in {1..50}; do
  run simulation &
done
wait

Upvotes: 0

Thomas
Thomas

Reputation: 182063

As you don't seem to want/need to wait until all simulations are done, you can simply do this:

for i in {1..50};
do
     { run simulation && parse output; } &
done

Upvotes: 3

jilles
jilles

Reputation: 11252

Use the wait builtin utility. See man bash for more information. In the simplest case, wait by itself will wait for all child processes to terminate.

Upvotes: 0

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