Exiting first process in pipe when second exists

Question

On sh or bash, how do I exit the first process in a pipe when the second one has exited?

I was using the following to get input from the network:

$ nc -l 1234 | myprog

myprog exited due to an internal cause but nc continues to live. Is it possible to stop nc also?

Perhaps you could use http://stackoverflow.com/questions/1908610/how-to-get-pid-of-background-process — Etheryte, Mar 26 '14 at 21:44
See http://www.tldp.org/LDP/abs/html/io-redirection.html for some options. — Etheryte, Mar 26 '14 at 22:17
Thanks but I have no idea how to use those notes to solve my problem. Any hints? — r.v, Mar 27 '14 at 16:20

score 1 · Accepted Answer · answered Mar 27 '14 at 21:10

1

In bash you can fork process with & control operator and get the pid of child reading $!. So, the simplest solution could be

$ ( nc -l 1234 & echo $! > /tmp/myprog_kill_pid ) | myprog; kill $(</tmp/myprog_kill_pid); rm /tmp/myprog_kill_pid

Of course, this is not very nice and not suitable for multiple running instances... but you can start from this.

answered Mar 27 '14 at 21:10

pmod

I did a workaround to my specific problem but thanks for telling how to fork using &. – r.v Mar 27 '14 at 22:09

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