Having recently returned to Linux after a twenty year hiatus, I'm currently enjoying OverTheWire as a good terminal refresher.
OverTheWire offers various wargames that let you practice and test your skills in security concepts. You can join the chat, visit the game pages, and connect to each game using SSH on different ports.
I used the bandit game as an in class exercise when I was teaching basic linux skills to aspiring system administrators. It was always a great success because everyone got to advance at their own pace. Plus, they felt like real hackers because it was really over ssh. Anyway, have fun!
Aye, it's a good educational tool for sure. It's nice to be playing around with Linux again. Installed Linux Mint to dual boot on my desktop about 2 months ago and liked it so much I installed it on my laptop then revamped an old desktop with Lxle in my shed. Booted into Windows two days ago just to check something and the damned thing decided to spend half an hour updating. That was the last straw for me. Shut it down, deleted the Windows partitions and updated the grub to remove any sign of the offending item. Apart from a couple of pieces of software that I haven't used in years, I'm now a fully-fledged Linux user. F*ck Windows!
Good for you! I've been free of windows for a decade I think. There's nothing I miss as most of the programs I like and need have linux versions. The main program holding me back was reaper, an audio editor, and when they released an alpha version for linux I erased my last windows hard drive. I only run debian stable, but I'm not too fussed with bells and whistles.