9.4. Special configuration in
The /etc/inittab has some special
features that allow init to react to special
circumstances. These special features are marked by special
keywords in the third field. Some examples:
Allows init to shut the system
down, when the power fails. This assumes the use of
a UPS, and software that watches the UPS and informs
init that the power is off.
Allows init to reboot the system, when
the user presses ctrl-alt-del on the console keyboard.
Note that the system administrator can configure the
reaction to ctrl-alt-del to be something else instead,
e.g., to be ignored, if the system is in a public
location. (Or to start nethack.)
Command to be run when the system is booted. This command
usually cleans up /tmp, for example.
The list above is not exhaustive. See your
manual page for all possibilities,
and for details on how to use the above ones.