On Mon, 14 Mar 2022 11:13:13 +0100
"J. Roeleveld" <jo...@antarean.org> wrote:
> Hi,
>
> I often put multiple commands into a single file/script to be run in sequence.
> (each line can be executed individually, there is no dependency)
>
> Is there a tool/method to execute multiple lines/commands simultaneously? Like
> having 3 or 4 run together and when 1 is finished, it will grab the next one
> in
> the list?
>
> I would prefer this over simply splitting the file as the different lines/
> commands will not take the same amount of time.
>
> Thanks,
>
> Joost
>
>
>
At the end there's a very rudimentary bash script to do this. I did not
do much debugging (probably it fails already if max_jobs>#list_of_jobs).
Anyway it's just making use of sending jobs to the background and
"communicating" through a FIFO pipe (which you might want to delete at
the end).
#!/bin/bash
list_of_jobs=("sleep 3" "sleep 5" "sleep 1" "sleep 10" "sleep 4")
max_jobs=2
my_fifo=/tmp/my_job_fifo
write_to_fifo="yes"
function run_job () {
eval "$@"
if [[ $write_to_fifo == "yes" ]]; then
echo "Writing to fifo ($@)"
echo 1 > ${my_fifo}
fi
echo Finished job "$@"
}
function read_and_start_job() {
next_job_idx=0
while [[ ${#list_of_jobs[@]} -gt $next_job_idx ]]; do
while IFS= read -r line ; do
echo "next_job_idx=${next_job_idx} total=${#list_of_jobs[@]}"
if [[ $next_job_idx -lt ${#list_of_jobs[@]} ]] ; then
job="${list_of_jobs[${next_job_idx}]}"
echo "Executing: ${job}"
run_job ${job} &
let next_job_idx++
else
echo "Set write_to_fifo=no"
write_to_fifo="no"
fi
done < ${my_fifo}
done
write_to_fifo="no"
wait
}
rm -Rf ${my_fifo}
mkfifo ${my_fifo}
read_and_start_job &
while [[ ${max_jobs} -gt 0 ]] ; do
let max_jobs--
echo 1 > ${my_fifo}
done
wait
