Linux is my favourite OS, and has been since I discovered it back in the 90's. I actually don't like the direction it's taken since then - Ubuntu et al are very helpful when you just want to get up & running quickly, but most of the Linux GUIs suck massively. Unity, Gnome 3, KDE 4 are just a few of the most recent examples of the problem.

Fortunately, the command line is where I prefer to be, and this remains an area of unparalleled excellence. There's a lot of little things that the CLI can do to make life easier, many of which aren't well known. So here's a bunch of things I find worth knowing: