Linux Shortcuts

Some additional KDE keyboard shortcuts (useful, but non-essential) 

<Alt><Tab> Walk through windows. To walk backwards: <Alt><Shift><Tab>
<Ctrl><Tab> Walk through desktops. To walks backwards: <Ctrl><Shift><Tab>
<Ctrl><Esc> Show the table of processes running on my system. Allow me to kill any of the processes I started (or send other signals to them).
<Alt><F1> Access the K-menu ("Equivalent to MS Windows "Start" menu).
<Alt><F12> Emulate the mouse using the arrow keys on the keyboard.
<Alt><LeftMouseButton> Drag a window to move it. Normally, I move a window by dragging its top title bar, but occassionally I manage to get it off the screen. With this shortcut, I can drag by any part of the window.
<Alt><PrintScreen> Take a snapshot of the current window into the clipboard.
<Ctrl><Alt><PrintScreen> Take a snapshot of the entire desktop into the clipboard.
<Ctrl><Alt><l> Lock the desktop.
<Ctrl><Alt><d> Toggle hide/show the desktop (great to hide the Solitaire game when your boss walks in).

<Alt><SysRq>
(Non-essential.) This is a group of key combinations implemented at the Linux kernel level (a low level). It means, chances are these key combinations will work most of the time. The combinations are meant for debugging purposes and in an emergency (mostly developers); you should try other, safer solutions first. The key <SysRq> is also knows on PC as <PrintScreen>. The combinations can be enabled/disabled by setting the relevant kernel variable to "1" or "0", e.g. : echo "1" > /proc/sys/kernel/sysrq
<Alt><SysRq><k> Kill all processes (including X) which are running on the currently active virtual console. This key combination is know as "secure access key" (SAK).
<Alt><SysRq><e> Send the TERM signal to all running processes except init, asking them to exit.
<Alt><SysRq><i> Send the KILL signal to all running processes except init. This may be more successful in killing runaway processes than the previous key combination, but it may cause some of them to exit abnormally.
<Alt><SysRq><l> Send the KILL signal to all processes, including init. The system will not be functional.
<Alt><SysRq><s> Run an emergency sync (cache write) on all mounted filesystems. This can prevent data loss.
<Alt><SysRq><u> Remount all mounted filesystems as read-only. This has the same effect as the sync combination above, but with one important benefit: if the operation is successful, fsck won't have to check all filesystems after a computer hardware reset.
<Alt><SysRq><r> Turn off keyboard raw mode. This can be useful when your X session hangs. After issueing this command you may be able to use <Ctrl><Alt><Del>.
<Alt><SysRq><b> Reboot immediately without syncing or unmounting your disks. Your will likely end up with filesystem errors.
<Alt><SysRq><o> Shut the system off (if configured and supported).
<Alt><SysRq><p> Dump the current registers and flags to your console.
<Alt><SysRq><t> Dump a list of current tasks and their information to your console.
<Alt><SysRq><m> Dump memory info to your console.
<Alt>SysRq><digit> The digit is '0' to '9'. Set the console log level, controlling which kernel messages will be printed to your console. For example, '0' will cause only emergency messages like PANICs or OOPSes displayed on your console.
<Alt><SysRq><h> Display help. Also, any other unsupported <Alt><SysRq><key> combination will display the same help.