One thing that came to me as news is that the command which—which is the de-facto tool
to find the path of an executable—is not POSIX compliant. The recent Debian [debacle]
(https://lwn.net/Articles/874049/) around which brought it to my attention. The
POSIX-compliant way of finding an executable program is command -v, which is usually
built into most of the shells.
So, instead of doing this:
which python3.10
Do this:
command -v which python3.10