Doing parallel processing in bash?
You can use xargs to run multiple processes in parallel:
find /path -print0 | xargs -0 -n 1 -P <nr_procs> sh -c 'pngcrush $1 temp.$$ && mv temp.$$ $1' shxargs will read the list of files produced by find (separated by 0 characters (-0)) and run the provided command (sh -c '...' sh) with one parameter at a time (-n 1). xargs will run <nr_procs> (-P <nr_procs>) in parallel.
You can use custom find/xargs solutions (see Bart Sas' answer), but when things become more complex you have -at least- two powerful options:
parallel(from package moreutils)- GNU parallel
With GNU Parallel http://www.gnu.org/software/parallel/ it can be done like:
find /path -print0 | parallel -0 pngcrush {} {.}.temp '&&' mv {.}.temp {} Learn more:
- Watch the intro video for a quick introduction:https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1
- Walk through the tutorial (man parallel_tutorial). You command linewill love you for it.