BusyBox has a minimal
init program that uses a configuration file,
/etc/inittab, to define rules to start programs at boot up and to stop them at shutdown. Usually, the actual work is done by shell scripts which, by convention, are placed in the
init begins by reading the configuration file,
/etc/inittab. This contains a list of programs to run, one per line, with this format:
The role of these parameters is as follows:
id: The controlling terminal for the command
action: The conditions to run this command, as shown in the following paragraph
program: The program to run
The actions are as follows:
sysinit: Run the program when
initstarts, before any of the other types of actions.
respawn: Run ...