Using grep directly could result in "binary file matches" without any
useful info.

This would happen e.g. after renaming some files with badly-encoded
filenames.  Bash history builtin seems to address such cases better.

These variables only make sense in interactive bash session where we
always re-read .bashrc anyway.

Mostly due to ls...

Turns out that these need to be often repeated

At least on Fedora this is tmpfs

In case of 2 parameters, the wrapper will short-circuit if the files are
same.

Name function right in the first place, instead naming it wrong and
renaming it using alias.