Once again reviewing good Linux sites, this time is the turn for BashCuresCancer, as its name suggests the site is devoted to command line uses.
I think it is a great site, and highly recommend you to subscribe to its RSS.
I can see the author likes CentOS a lot (like me), and lots of its tutorials are based on CentOS, but the command line is basically the same for every Linux Distribution, so it does not matter which Distro you are using, you will learn a lot reading BashCuresCancer.
The clear colors also make it easy to read, I like the minimalistic style the blog actually has.
The tutorials on this site, are easy to follow, step by step with lots of screen shots so you can not get lost.
Hope you enjoy and find it useful.
Congratulations to the author.