Reference Cards

4ltrwrd (1-UP) or 4ltrwrd (2-UP) !!!!!!!!!!!!!!
From Unix is a Four Letter Word...
unix-refcard.pdf !!!!!!!!!!!!!!
vi Reference Card (HP).pdf !!!!!!!!!!!!!!
emacs.pdf !!!!!!!!!!!!!!
vi is the most widely available editor in Unix systems - it's small, fast and uses nice, cryptic commands...
emacs is another, quite widely available editor - it's programmable (in Lisp), can do everything and programmers usually love it (cause it's programmable and has special modes for most programming languages, so that you don't need to use Godgilla - uh, I meant Eclipse/Netbeans/et al.).
Also (in no particular order - OK so it's in the order of ls...):
Bash Quick Reference.pdf
C Reference Card (ANSI).pdf
CVS Quick Reference Card (LG).pdf
CVS Quick Reference Card.pdf
JAVA Programming Guide - Quick Reference.pdf
JAVA Quick Reference.pdf
STL Quick Reference 1.26.pdf
The One Page Linux Manual.pdf
UML Quick Reference Card.pdf
UML Reference Card.pdf
UNIX commands reference card.pdf
cref.pdf
gdb-guide.pdf
gdbref.pdf

To learn more about a command (e.g., ls): man ls (gives you the manual page of the command) or info ls (gives you the info page of the command, usually with much more information than the manual page). A command may only have one of the aforementioned (and sometimes none so that the adventure is even more fulfilling...)

Try:
man man info info

And remember! Spaces in filenames need to be escaped with a backslash as in:
ls ~/My\ Documents

May the command line be with you...

FINAL WARNING

Avoid the use of rm for deleting files, since in Unix, when you delete something, you really delete it - there's no way back... Better remove things from the GUI explorer thing, till you get a bit more experience with Unix (about 60 years - trust me, I screw up quite often...).

Don't come back to me crying that you've lost all your files, even the ones you haven't created yet! That's called a "right of passage", for which you should be thankful... ;-)