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Re: SIGINT handling

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2015-09-22 12:04:45 -0600, Bob Proulx:
> Greg Wooledge wrote:
> > Just for the record, ping is the *classic* example of an incorrectly
> > written application that traps SIGINT but doesn't kill itself with
> > SIGINT afterward.  (This seems to be true on multiple systems -- at
> > the very least, HP-UX and Linux pings both suffer from it.)
> 
> The command I run into the problem most with is 'rsync' in a loop.
> 
>   EXIT VALUES
>        0      Success
>   ...
>        20     Received SIGUSR1 or SIGINT
> 
> Which forces me to write such things this way.
> 
>   rsync ...
>   rc=$?
>   if [ $rc -eq 20 ]; then
>     kill -INT $$
>   fi
>   if [ $rc -ne 0 ]; then
>     echo "Error: failed: ..." 1>&2
>     exit 1
>   fi
[...]

Another (generic) work-around as mentioned at
http://unix.stackexchange.com/a/230568
and here is to add:

trap '
  trap - INT
  kill -s INT "$$"
' INT

That doesn't work properly if there are subshells though.

That basically turns a WCE shell to WUE (for very simple scripts).

For SIGQUIT, you'd probably want to disable core dumps as well:
  
trap '
  trap - QUIT
  ulimit -c 0
  kill -s QUIT "$$"
' QUIT

-- 
Stephane

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Re: SIGINT handling Stephane Chazelas <stephane.chazelas@gmail.com> - 2015-09-22 19:20 +0100

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