Add command to queue and execute it after the last one finish --task-spooler

task-spooler (ts)
/* for ubuntu, it is tsp */
task spooler is a Unix batch system where the tasks spooled run one after the other. The amount of jobs to run at once can be set at any time. Each user in each system has his own job queue.

sudo apt-get install task-spooler








Redirecting process output in Task Spooler
          tsp command --with arguments \> logfile
kill
           kill $(tsp -p job_id)

you can change the maximum number of jobs running at once with the -S [num]
       parameter.
if you set tsp -S 4, task spooler would run the first 4 jobs and queue up the next. Once one of the original 4 jobs completed, the next queued up job (based on lowest job id) would then begin. This would continue to happen as running jobs finish and more slots open up.


EXAPMLES:
https://www.ostechnix.com/add-linux-commands-queue-execute-one-one/
https://www.linux.com/news/queuing-tasks-batch-execution-task-spooler/


Reference:
https://vicerveza.homeunix.net/~viric/soft/ts/
https://superuser.com/questions/1466845/redirecting-process-output-in-task-spooler
http://manpages.ubuntu.com/manpages/xenial/man1/tsp.1.html
https://stackoverflow.com/questions/48497875/how-to-run-5-shell-job-simultaneous-and-keep-rest-in-queue