In your examples you fail to put 'xargs -P' in the middle of a pipeline: You only put it at the end. In other words: some command | xargs -P other command |

In your examples you fail to put 'xargs -P' in the middle of a pipeline: You only put it at the end. In other words: some command | xargs -P other command | third command This is useful if 'other command' is slow. If you buffer on disk, you need to clean up after each task: Maybe there is not enough free disk space to buffer the output of all tasks. UNIX is great in that you can pipe commands together, but due to the interleaving issue 'xargs -P' fails here. It does not live up to the UNIX philosophy. Which is probably why you unconsciously only use it at the end of a pipeline. You can find a different counterexample on https://unix.stackexchange.com/questions/405552/using-xargs-instead-of-gnu-parallel https://unix.stackexchange.com/questions/405552/using-xargs-... I will be impressed if you can implement that using xargs. Especially if you can make it more clean than the paralel version.