Bash if command doesn't finish in X time?

Question

I'm trying to run something like:

sudo dhclient $wifi || otherFunction

Problem is when dhclient fails it just hangs instead of throwing an error.

How can I re-write the above so dhclient is killed and otherFunction gets called if dhclient doesn't finish in 60 seconds?

score 18 · Accepted Answer · answered Nov 17 '17 at 20:21

18

Your timeout tag gives it all away:

sudo timeout 60 dhclient $wifi || otherFunction

An example:

sudo timeout 3 sleep 5 || echo finished early

This uses the timeout utility provided by the GNU coreutils package on Linux.

answered Nov 17 '17 at 20:21

Jeff Schaller

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doesn't work on MacOS unfortunately – Alexander Mills Apr 20 '18 at 22:13
`timeout` for MacOS: https://stackoverflow.com/a/21118126/451480 – Blaise Feb 10 '19 at 21:29
If you want to check specifically for `timeout` killing the command (as opposed to the command failing for other reasons), check for exit status 124. – muru Jun 26 '19 at 08:48

score 2 · Answer 2 · answered Nov 17 '17 at 20:22

2

Use timeout.

timeout 2 sleep 1
echo $?
0

timeout 1 sleep 2
echo $?
124

answered Nov 17 '17 at 20:22

Matt Clark

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doesn't work on MacOS unfortunately – Alexander Mills Apr 20 '18 at 22:13

score 2 · Answer 3 · answered Aug 16 '18 at 01:21

Use the timeout packed as gtimeout with the coreutils port in brew:

brew install coreutils
gtimeout --help

That'll work with /usr/local/bin in your PATH. If you want to use timeout as originally named, add /usr/local/opt/coreutils/libexec/gnubin to your PATH.

Bash if command doesn't finish in X time?

3 Answers3