r Turns off keyboard raw mode and sets it to XLATE
k Kills all programs on the current virtual console
b Will immediately reboot the system without syncing or unmounting your disks
o Will shut your system off via APM (if configured and supported)
s Will attempt to sync all mounted filesystems
u Will attempt to remount all mounted filesystems read-only
p Will dump the current registers and flags to your console
t Will dump a list of current tasks and their information to your console
m Will dump current memory info to your console
0-9 Sets the console log level, controlling which kernel messages will be printed to your console (0, for example would make it so that only emergency messages like PANICs or OOPSes would make it to your console)
e Send a SIGTERM to all processes, except for init
i Send a SIGKILL to all processes, except for init
l Send a SIGKILL to all processes, INCLUDING init (Your system will be non-functional after this)