GNU Parallel
As always gets brought up when GNU parallel is mentioned: xargs does most of the use cases you'd need for parallel.<p>xargs -n1 -P4<p>Would be at most one arg from the arg list run with 4 jobs.
 <a href="http://stackoverflow.com/questions/28357997/running-programs-in-parallel-using-xargs" rel="nofollow">http://stackoverflow.com/questions/28357997/running-programs...</a>