Need a quick reference card? Here you have a list you can choose from:
1.Linux Command Line Tips
This is a linux command line reference for common operations (HTML format).
2.Unix/Linux Reference Card
Linux Reference Card published on FOSSwire website by Jacob. (PDF format)
3.One Page LInux Manual
A summary of useful Linux command by Squadron. (PDF format)
4.Linux Security Quick Reference
The intent of this Quick Reference Guide is to provide a starting point for improving the security of your system, to serve as a pointer to more in-depth security information, and to increase security awareness and methods that can be used to improve security. (PDF format)
This cheat sheet summarizes all they default keyboard mappings, with screen’s commands to execute the mapping and a description of each mapping. (PDF format)
There comes a time when one needs an end-all reference to the system. The time is now, and if you’re an Ubuntu user you’ll like this cheat sheet. (PDF format)
Probably the best Vim Cheat Sheet: “This is a single page describing the full vi/vim input model, the function of all keys, and all major features. You can see it as a compressed vi/vim manual. ” (GIF format)
Read more >> (Update: the link is down. I’m sorry)
a non-geek's blog 
Hi! Thanks for linking to my Screen cheat sheet!
I’d like to let you know that I have 8 other Linux related cheat sheets!
Please see the Cheat Sheets section on my blog!
I have Awk, Ed, Sed, Perl and Bash cheat sheets there!
Sincerely,
Peteris Krumins
Wowww! Very good man!
Thanks!
I enjoy cheat sheet a lot 😉
Thanks again!
I enjoy cheat sheets to, that’s way I wrote this poste. I’m glad you like it. I hope you’ll find useful my next post that I will publish friday 😉
Regards,
Marius
Definitely nice collection!!! Really nice! Keep it up!
@Zico
Thank you. I’m very glad to see that you, and other people really like my posts. That’s why I will not stop. Thanks again Zico!
Hi,
Thanks. Comes in handy
i m a geek
Awesome…bookmarked and will checkout your other blogs!
Thanks. I hope you’ll like them too.
С пивом покатит:)
Debian Reference Card is now updated at: http://xinocat.com/refcard/
with translations to many languages!
article, of course, good, but something it lacks.
Честно, давно не читал статью сразу и полностью, не отрывался даже на сообщения из аси. Надеюсь продолжение будет не менее интересным…
cool tips
i need this info many month ago
finally, thanks for this reference…
Thank’s very much.
Glad you find it useful
THnaks For buch of work
Have to love handy reference cards. I mean who really has the time to remember all of this 🙂
There are nowadays also a bunch of nice apps available. For instance:
https://play.google.com/store/apps/details?id=nl.atcomputing.refcard
Another good cheat sheet can be found here: http://linuxtutorial.todolistme.net/cheatsheet.php It’s good as you can hide sections you’re familiar with so you only see the valuable stuff. Also has links to a tutorial so if you need any more information on any section it’s right there for you.