BusyBox init

BusyBox has a minimal init program that uses an /etc/inittab configuration file to start programs at bootup and stop them at shutdown. The actual work is done by shell scripts, which, by convention, are placed in the /etc/init.d directory.

init begins by reading /etc/inittab. This file contains a list of programs to run, one per line, in this format:

<id>::<action>:<program>

The roles of these parameters are:

• id: The controlling terminal for the command
• action: When and how to run the program
• program: The program to run along with all its command-line arguments

The actions are:

• sysinit: Runs the program when init starts before any of the other types of actions.
• respawn: Runs the program and restarts it if it terminates. It is used to run a program as a daemon.
• askfirst: The same as respawn, but it prints the message Please press Enter to activate this console to the console and runs...