Re: Parallelism a la make -j <n> / GNU parallel

[Greg Wooledge]

On Fri, May 04, 2012 at 09:02:27PM +0200, John Kearney wrote:
> set -m
> cnt=0
> trap ': $(( --cnt ))' SIGCHLD
> set -- {0..20}
> while [ $# -gt 0 ]; do
>       if [[ ${cnt} -lt 10 ]] ; then
> 
>               (
>                       d=$(( RANDOM % 10 ))
>                       echo $n sleeping $d
>                       sleep $d
>               ) &
>               : $(( ++cnt ))
>               shift
>       fi
>       echo going to wait
>       sleep 1
> done

You're busy-looping with a 1-second sleep instead of using wait and the
signal handler, which was the whole purpose of the previous example (and
of the set -m that you kept in yours).  And $n should probably be $1 there.