How to quickly reboot you Linux

Here is a quick way to reboot you Linux with kexec command. In debian first install kexec-tools package:

apt-get install kexec-tools

Once installed make your current kernel the one you want to quickly reboot into:

kexec -e

In case you would like disable fast reboot, open file located at /etc/default/kexec and set LOAD_KEXEC to false:

# Defaults for kexec initscript
# sourced by /etc/init.d/kexec and /etc/init.d/kexec-load

# Load a kexec kernel (true/false)
LOAD_KEXEC=true

# Kernel and initrd image
KERNEL_IMAGE="/vmlinuz"
INITRD="/initrd.img"

# If empty, use current /proc/cmdline
APPEND=""