Yes, running in background and checking the status of the pid is coming to mind when one has to do that Bash. I always feel that it's stretching beyond the normal level of usage. For example what can you do with the output? There is no way to sync it unless you'll capture it in a file and analyze later. In cases when I need to write something parallelized I feel that using Bash isn't the best idea.

Yeah, I agree, but there are some use cases for a simple bash script. I updated the GIT repo with a PHP version that has output and errors like you said.