Your `do_one`: * does not buffer stderr * does not check if the disk is full for a period of time during a task (thus risking incomplete output) * does n

Your `do_one`: * does not buffer stderr * does not check if the disk is full for a period of time during a task (thus risking incomplete output) * does not clean up, if killed * does not work correctly if task_with_stdout is a composed command Given that GNU Parallel is a drop-in replacement for xargs, I am curious why you find it a 'weirdo interface'.