Stopping an infinite loop and breaking at end of loop

Question

I'm running an infinite while loop in bash that has a counting element to it.

while :
do
    #stuff including counting
    trap break int
done

This works as I would like for the most part. When I hit Ctrl+C, the loop stops, but the script continues. However, the loop stops in the middle of the loop which means that the final count is inaccurate.

Is there a way to make this loop break at the very end?

If one of the answers here resolved your question please accept that answer. Accepting an answer closes this questions and rewards the author of the accepted answer. If your question was not resolved consider explaining why. — Socowi
– Socowi, Commented Feb 15, 2019 at 12:03

Socowi · Accepted Answer · 2019-02-06 15:27:13Z

4

Instead of executing break you can set a flag and break the loop at a designated location when the flag is set. Note that in a loop the loop head can also be seen as the very end of the loop.

state=run
trap 'state=end' int
while [ "$state" = run ]
do
    # stuff
done

If you want to break somewhere in the middle use

state=run
trap 'state=end' int
while :
do
    # stuff
    [ "$state" = end ] && break
    # more stuff
done

You can test the behavior quiet nicely by replacing # stuff with for i in {1..20}; do printf .; sleep 0.1; done; echo:

As we can see in the clip above, the outer loop finishes its current iteration (# stuff) until the very end.

edited Feb 6, 2019 at 15:27

answered Feb 6, 2019 at 15:06

Socowi

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