Get the path of commands using "realpath" and "which"

Sometimes you need to load resources that are relative to some tool. On POSIX (with a compatible shell), you can use:

realpath $(which command)

This finds the absolute path (including resolving links) to the command named command which is on PATH.

And if you need to run a command in the directory of a tool:

pushd $(dirname $(realpath $(which command)))
command ...
popd