[Wikipedia](https://en.wikipedia.org/wiki/Regular_expression) explains it better than me.
## Wildcards?
Wildcards are similar to regex but a lot simpler.
A quick [tutorial](https://linuxhint.com/bash_wildcard_tutorial/) explains it better than me.
## Var log msg?
The debian system administrator gives a good [overview](https://debian-handbook.info/browse/stable/sect.filesystem-hierarchy.html) of the directory structure of the linux OS.