# The "magic SysRq key" provides a way to send commands
# directly to the kernel through the /proc filesystem
# kernel documentation: https://www.mjmwired.net/kernel/Documentation/sysrq.txt
# using keyboard: Alt-SyqRq-KEY

# activate the magic SysRq option (root)
echo 1 > /proc/sys/kernel/sysrq

# activate the magic SysRq option (sudo)
echo 1 | suto tee /proc/sys/kernel/sysrq

# permanently activate sysrq
echo "kernel.sysrq = 1" >> /etc/sysctl.conf

# k – Kills all the process running on the current virtual console.
# s – This will attempt to sync all the mounted file system.
# b – Immediately reboot the system, without unmounting partitions or syncing.
# e – Sends SIGTERM to all process except init.
# m – Output current memory information to the console.
# i – Send the SIGKILL signal to all processes except init
# r – Switch the keyboard from raw mode
#     (the mode used by programs such as X11), to XLATE mode.
# s – sync all mounted file system.
# t – Output a list of current tasks and their information to the console.
# u – Remount all mounted filesystems in readonly mode.
# o – Shutdown the system immediately.
# p – Print the current registers and flags to the console.
# 0-9 – Sets the console log level, controlling which kernel messages will be
#     printed to your console.
# f – Will call oom_kill to kill process which takes more memory.
# h – Used to display the help (any key except the listed above will print help)