Top 10 tips for the Linux command line:
(email this to ten friends!)
If you don't know about "foo", type:
10 "info foo"
or
9 "man foo"
if you can't find "foo", type:
8 "locate -i foo"
or
7 "whereis foo"
if you want to view "foo":
6 "less foo"
or
5 "emacs foo"
4 just about any program, when you type it's name and "-h" or "--help" will print out a usage message.
3 to navigate "down" into a directory named foo, type "cd ./foo"
2 to navigate "up" into any higher directory, type "cd ../"
1 to see what's in the directory that you're in, type "ls"
and bonus rule 0: read everything readable in your system. You practically have a library at your fingertips! Start in /usr/doc, /usr/share/doc, /usr/share/info, /usr/man or /usr/doc/man. Depending on which is what on your system.
Here's the standard place to look for docs: we have man pages, HOWTOs, and html guides here:
http://www.tldp.org/index.html
And my own little welcome to Linux from Windows speech:
Hi, I came from Windows not so long ago myself! Cramped in that cave, wasn't it?
The sense you feel right now, is one of being overwhealmed. Some of the reason for that is, you have about ten times as much operating system as you used to have! Once you poke around, you'll find out that Linux makes up for this by making their programs much smaller. "Do one thing simply and well." is one of the mottos. Where other OSs have one program try to be everything to everyone, Linux takes ten programs and stacks them together like Legos to do whatever custom function you had in mind. However, we also have a saying, "The learning curve is steep, but you only have to climb it once." That is, once you've gotten the hang of using "regular expressions" to search for files with "find", you'll find "grep" and "sed" use the same scheme. Once you've found out that "info" and "man" exit with the letter "q", it will come as second nature to exit with "q" in "less".
You'll notice that the names of all of our programs sound funny. That's because absolutely everything is an acronym for everything else. Just use the doc-searching methods I outlined above.
I always tell people using Linux for the first time, "Hope you like to read!" If you're manual-shy from other operating systems, you're in for a surprise: Linux manuals actually try to help you by telling you the straight facts, without insulting your intelligence, and without trying your patience prattling along about the 16 ways to select a fancy purple script font when you want to know how to save the file.
Of course, these days, Linux can be used mostly from the GUI desktop, so just stay there for awhile. Find something called a "terminal" or "console" to try all this typing stuff in. In the meantime, every program you start should have a "help" menu somewhere in the upper right corner, or look for the sign of the red-and-white life preserver somewhere on the menus. Most of the desktop apps will feel at home to a Windows user: The "home" icon usually starts the system file browser, similar to the concept of "file manager" or "Explorer". "OpenOffice" should be comparable to "Word". Instead of "Paintbrush", we have "The Gimp". "Gaim" is an "Instant Messenger", and so on...
Don't get too worked up. Pace yourself. I've been using Linux for a couple years, and still discover something new every day.