How to save both matching and non-matching from grep

Question

I use grep very often and am familiar with it\'s ability to return matching lines (by default) and non-matching lines (using the -v parameter). However, I want to be able to

Answer 1

I had the exact same problem and I wrote a small Perl script for that [1]. It only accepts one argument: the regex to grep input on.

[1] https://gist.github.com/tonejito/c9c0bffd75d8c81483f9107c609439e1

It reads STDIN by line and checks against the given regex, matched lines go to STDOUT and not matched go to STDERR.

I made it this way because this tool sits in the middle of a pipeline and I use shell redirection to save the files on their final location.