What Happens When the System Is Brought to Run Level 3

The init process is started and reads the /etc/default/init file to set any environment variables.
Then init reads the inittab file to do the following:
- Identify the initdefault entry, which defines the default run level (3).
- Execute any process entries that have sysinit in the action field so that any special initializations can take place before users login.
- Execute any process entries that have 3 in the rstate field, which matches the default run level, 3.

The init process is started and reads the /etc/default/init file to set any environment variables.