Recently I needed to multiplex stdin to both stdout and stderr and was surprised that none of the coreutils tools supported that. The closest is `tee /dev/stder

Recently I needed to multiplex stdin to both stdout and stderr and was surprised that none of the coreutils tools supported that. The closest is `tee /dev/stderr` which only works on system where stderr is bound to that virtual device. It seems such a basic thing to do when you want to debug a pipe.