Some useful, and interesting, cli commands

I got these from this blogpost (indeed, most came from the comments):

faillog

lets you see failed login attempts so you'll see if anyone tried to guess your password

sudo !!

types the previous command but with sudo (install sudo !! first)

mpg123

need to install to play a music file (but I haven't yet got this to work)

sl

again need to install. Run to see a moving train

tload see scrolling system load

cd -

moves back one directory (like cd ..) AND displays path of new directory

pushd/popd Allow directory stacking

Also provided is this link for Linux tutorials (haven't yet looked at this).