For someone who once had to exclusively use Linux at work for several years, my knowledge of bash is extremely mediocre. Luckily, there are a wide range of references and tutorials out there.

Explain Shell: Type in any command line and have it broken down and explained, piece by piece.

tldr: A more readable version of man pages for commonly used commands.

Command Line Crash Course: Mostly covers the basics that I already knew, but it's still a good place to get started.

Humble Bundle Unix Books: This bundle is still active for about four more days and includes pretty much all the O'Reilly guides you would ever need. I've been meaning to purchase the one on sed and awk for a while now since I don't know how to use either.

And now for the functional programming half...

Functional Programming Design Patterns: Slides and video for a talk on functional programming design patterns, which was linked in the 8th Light company Slack. I didn't entirely digest a lot of the principles he describes in the talk, so it's definitely a link I hope to revisit and ponder more deeply.

OO vs FP: Blog post by Uncle Bob, in part a reaction to the above. It lays out the case that object-oriented programming and functional programming are not such fundamentally different paradigms and that the same design patterns used in object-oriented programming can be used in functional programming as well.

Adopting FP: The Good, the Familiar, the Unknown: Talk given by our CTO at the inaugural Chicago Software Craftsmanship Meetup. Also makes a similar case that a lot of the design principles and patterns from object-oriented programming may be transferrable or have their equivalents in functional programming.