As for your professional use (sysadmin), just study the heck out of 'bash', I find new uses for it on almost a daily base (and also daily forget about it's substitute syntax as ${FOO//bar/baz/} etc.).

A lot of people think bash is just for looping some GNU tools together. It is more powerful than that ... but then again, you're a sysadmin, so you probably already can dream the manual pages ;)

Substitute 'bash' with your favorite shell in this post