For simplish parallel runner https://www.gnu.org/software/parallel/ is excellent, can even automate stuff like "copy a file to remote server then run command on it" so you can make simplistic cluster computing with it
e.g. `ls old/*.jpeg | parallel mv {} new/{/.}.jpg` is easier than a bash loop.[1]
[1] Yes, it should be `find -print0` or something, blah blah, it's an example.
For simplish parallel runner https://www.gnu.org/software/parallel/ is excellent, can even automate stuff like "copy a file to remote server then run command on it" so you can make simplistic cluster computing with it