Linux

Linux Shortcuts and Commands:
Linux Newbie Administrator Guide
by Stan and Peter Klimas
This is a practical selection of the commands we use most often. Press <Tab> to see the listing of all available command (on your PATH). On my small home system, it says there are 2595 executables on my PATH.  Many of these "commands" can be accessed from your favourite GUI front-end (probably KDEor Gnome) by clicking on the right menu or button. They can all be run from the command line.  Programs that require GUI have to be run from a terminal opened under a GUI.
Legend:
<> = single special or function key on the keyboard. For example <Ctrl> indicates the "control" key.
italic = name of the file or variable you probably want to substitute with your own.
fixed width =in-line Linux commands and filenames.
Notes for the UNIX Clueless:
1. LINUX IS CASE-SENSITIVE. For example: Netscape, NETSCAPE and nEtscape are three different commands. Also my_filE, my_file, and my_FILE are three different files. Your user login name and password are also case sensitive. (This goes with the tradition of UNIX and the "c" programming language being case sensitive.)
2.Filenames can be up to 256 characters long and can contain letters, numbers, "." (dot), "_" (underscore), "-" (dash), plus some other not recommended characters.
3. Files with names starting with "." are normally not shown by the ls (list) or dir commands. Think of these files as "hidden". Use ls -a  (list with the option "all") to see these files.
4. "/" is an equivalent to DOS "\" (root directory,meaning the parent of all other directories).
5. Under Linux, all directories appear under a single directory tree (there are no DOS-style drive letters).
6. In a configuration file, a line starting with # is a comment.
7.1 Linux essential shortcuts and sanity commands
<Ctrl><Alt><F1>
Switch to the first text terminal. Under Linux you can have several (6 in standardsetup) terminals opened at the same time.
<Ctrl><Alt><Fn> (n=1..6)
Switch to the nth text terminal.
tty
Print the name of the terminal in which you are typing this command.
<Ctrl><Alt><F7>
Switch to the first GUI terminal (if X-windows is running on this terminal).
 <Ctrl><Alt><Fn> (n=7..12)
Switch to the nth GUI terminal (if a GUIterminal is running on screen n-1). On default, nothing is running on terminals
8 to 12, but you can run another server there.
 <Tab>
(In a text terminal) Autocomplete the command  if there is only one option, or else show all the available options.
THIS SHORTCUT IS GREAT! It even works at LILO prompt!
 <ArrowUp>
Scroll and edit the command history. Press <Enter> toexecute.
 <Shift><PgUp>
Scroll terminal output up. Work also at the login prompt, so you can scroll through your bootup messages.
 <Shift><PgDown>
Scroll terminal output down.
 <Ctrl><Alt><+>
(in X-windows) Change to the next X-server resolution (if you set up the X-server to more than one resolution). For multiple resolutions on my standardSVGA card/monitor, I have the following line in the file /etc/X11/XF86Config (the first resolution starts on default, the largest determines the size of the "virtual screen"):
Modes "1024x768" "800x600" "640x480" "512x384" "480x300" "400x300" "1152x864"
<Ctrl><Alt><->
(in X-windows) Change to the previous X-server resolution.
<Ctrl><Alt><BkSpc>
(inX-windows) Kill the current X-windows server. Use if the X-windows server crushes and cannot be exited normally.
<Ctrl><Alt><Del>
Shut down the system and reboot. This is the normal shutdown command for a user at the text-mode console. Don't just press the "reset" button for shutdown!
<Ctrl>c
Kill the current process (mostly in the text mode for small applications)....