Modern gnu xargs(1) supports --max-procs/-P to run parallel invocations of the target command.
Or, gnu parallel(1) is designed from the start to run its target command in parallel. Modern bsd xargs(1) also supports -P. See their man pages for details. -JimC -- James Cloos <cl...@jhcloos.com> OpenPGP: 0x997A9F17ED7DAEA6