You know any?

Um, that question is a bit vague. It depends on what the user is doing, really.

yeah... I just figured that out too... :(

The sequence of keys required to exit Emacs or Vi in console mode. (Ctrl-x Ctrl-c for Emacs... I don't use Vi)

In vi or vim, go into insert (editing) mode by pressing 'i', get out by pressing esc. You have to be out of it to give meaningful commands to vi. For example, ':w' saves, ':q' quits, ':wq' saves and quites. If you type those while in insert mode, it will merely type ":w", ":q", or ":wq" respectively.

From a shell console, you can type man to see the man (manual) pages for most commands, including the shell itself. So if you are operating in a bash shell, type 'man bash' to see the manual for bash presented to you in a very vi-like environment... meaning just like in vi, :q quits, '/expr' will search for the expression, 'n' will move to the next instance of that expression, etc.

Thingz:

Debian
kernel
BG-Rescue disk
vim
fluxbox
firefox
gkrellm*
ethereal*

Skillz:
C++
Perl
Howtos

This is basically what you need in order to do what you came to do.
* - Not essential

How to ask smart questions.

I'll do my best here.... Shell commands and scripting will get you very far. High level languages (like PHP - C) are not linux specific so I'm gussing you want linux specific stuff.

Commands I most commonly use - Look them up.. and you'll have a good start. You could read the man pages for each one but that's torture. Get a good book from O'Reilly at Amazon. Get to know vi.. really.. most distrabutions (most of unixland really) have vimtutor, a binary that you can run and it will give you a little tutor. Also, look in your /etc dirrectory and pick some random files to learn about. It's the single most important dirrectory around and has most of your system configuration.

grep
top
head
tail
ps
ls
awk
sed
chmod
chown
useradd
userdel
mv
cp
rm
who
last
wall
tar
gzip
file
diff
sort
cat

shutdow, reboot and halt. -- Listed last because a good admin should not use them often! =)

Command redirrection and piping (How to make two commands do something special)

Network Related Commands:
dig
nslookup
ping
tcpdump
ifconfig
netstat

Thats a nice list.
Other utilities I use more or less on a daily basis:

morelessfinddmesglocate  (usually not installed by default)killunametee     (can be useful every now and then)mkdirrmdirmountumountpatchlsmodmodprobermmod

Network Related Commands:

route   (can be replaced by ifconfig I think)fping   (better than ping if used in a shell script)nmap    (usually not installed by default. netstat can replace this)

Another directory you want to use is /proc.
This directory keep kernel related info.
examples:

cat /proc/filesystems  (filesystems supported by the running kernel)cat /proc/pci          (a listing of pci cards attached to your PC bus. The command lspci -vvv gives a more readable output though)cat /proc/modules

Another interresting directory is /var/log (on most distros)
This is where programs/servers output their log files

Its quite common to have a terminal dedicated to tracking a log file with the command:
$ tail -f /var/log/messages (or some other log file)

Another common trick is to look for patterns with the pipe/grep combination:
$ ps -ax | grep mozilla (or some other running program)

A typical example of killing a crashed mozilla:
$ ps -ax | grep mozilla
...
1024 ... mozilla ...
...
$ kill -9 1024

Sometimes you need to dump the output of dmesg to a forum (like this).
Use redirection to save the dmesg output:
$ dmesg > dmesg.txt
Then copy/paste the contents of dmesg.txt

Most important skill: know where to get help. Second: What Ravuya posted. Third: How to use the internet (and especially Google) effectively.