Part 1: Built-In System Keyboard Shortcuts
Windows & Linux
Everyone should already know:
Control-Alt-Delete - on Linux, it depends on the distribution. On Ubuntu Jaunty, it brings up the shutdown screen. But you can make it have a similar effect to Windows: open the System Monitor.
Alt + Tab - Switches between opened applications.
Alt + F4 - Closes the window
Alt + PrintScreen (Not all Linux)
I assume everyone knows that the middle mouse button on Linux uses a different 'cut buffer' than Ctrl + C. Glipper http://glipper.sourceforge.net/ is a Gnome applet to share and provide multiple buffers, easier than Microsoft Office.
Windows
Does anybody use the Menu key?
Commands that follow holding the Windows modifier key:
D Shows the Desktop
E Windows Explorer (file manager)
L Login (switch user)
R Run Brings up the Run box. Enter cmd and you'll never need touch the mouse!
F Find
Unix (Linux) and X Window
Ctrl + Alt + D - Show the Desktop
Ctrl + Alt + F1 through F6 Switch to a shell (aka virtual terminal)
Ctrl + Alt F7 Switch back to X Window (Alt F5 on Knoppix)
Ctrl + Alt + Backspace Kill -9 X Window; Linux kernel and system daemons keep running
Ctrl + d = logout of (and close) shell prompt
Ctrl + Alt + L - Lock the screen quickly
Commands that follow holding the Alt + SystemRequest keys:
B Reboot Ubuntu
O Shutdown
K Kill -9 the foremost process
R + E + I + S + U + B - safe restart. Holding Alt + System Request, type REISUB which means:
* R: Switch the keyboard from raw mode to XLATE mode
* E: Send the SIGTERM signal to all processes except init
* I: Send the SIGKILL signal to all processes except init
* S: Sync all mounted filesystems
* U: Remount all mounted filesystems in read-only mode
* B: Immediately reboot the system, without unmounting partitions or syncing
REISUO will do a safe shutdown instead of restart
Ubuntu (Gnome) (other distributions too)
Alt + F1 - Opens the applications menu
Alt + F2 - Run an application by typing its name in the box which appears
Alt + F7 - Moves the current window (can be moved with mouse or keyboard).
Alt + F8 - Resizes current window (again,can be moved with mouse or keyboard).
Alt + F9 - Minimizes current window.
Alt + F10 - Maximizes current window.
Alt + Space - Brings up window menu with with 'Always on Top' and 'Minimize' and 'Maximize' and above commands.
Alt + F5 - Returns window to 'normal' or previous size.
Ctrl + Alt + Plus (numeric keypad) - Rotate through supported screen resolutions
Ctrl + Alt + Minus (numeric keypad) - Rotate backwards through supported screen resolutions
Desktop effects enabled:
Ctrl + Alt + Left/Right - Switch to the next/previous workspace
Shift + Ctrl + Alt + Left/Right Arrow - Move the current window to another workspace
Shift + F10 - Right click effect
Alt + F7 - Move windows with arrow keys
Ctrl + H - Show hidden files.
Alt + Enter - Show file properties without right-clicking the mouse
Terminal commands:
Ctrl + l = clears the terminal.
Ctrl + u = clears the current line. If you are working in a terminal, use this shortcut to clear the current line from the cursor all the way to the beginning of the line.
Ctrl + C - Kill process (Kill the current process in terminal, also used to copy elsewhere)
Ctrl + Z - Send process to background
Ctrl + D - Log out from the current terminal. In X, this may log you out after a shuting down the emulator.
Ctrl + A - Home (Move cursor to beginning of line)
Ctrl + E - End (Move cursor to end of line)
Tab - List available commands from typed letters (Ex: type iw and click tab, output = iwconfig iwevent iwgetid iwlist iwpriv iwspy)
Ctrl + U - Delete current line
Ctrl + K - Delete current line from cursor
Ctrl + W - Delete word before cursor in terminal (Terminal only, also used to close the current document elsewhere)
Arrows up and down = Browse command history
Ctrl + R - History search (Finds the last command matching the letters you type)
Shift + PageUp / PageDown - Scroll terminal output
Ctrl + L - Clears terminal output
Shift + insert - Paste