Ctrlaltdel
ctrlaltdel is a utility included as part of the util-linux package on most distributions.
The purpose of ctrlaltdel is to allow the system administrator to control the behavior of the Ctrl+Alt+Del key combination.
Usage
ctrlaltdel is used by issuing the command at a shell prompt, as follows.
ctrlaltdel hard
Using this option will cause the system to reboot immediately upon pressing the Ctrl, Alt and Delete keys simultaneously.
ctrlaltdel soft
This will cause the SIGINT signal to be sent to the init process (pid 1), which must support the feature. From there the init process will handle rebooting the system, and any preparation required.
Invoking ctrlaltdel without any options will print the current setting to standard output.
ctrlaltdel also supports the somewhat standard options --version which displays the version information, and --help which will print a brief summary of allowable options and usage.