/etc/inittab File

When you boot the system or change run levels with the init or shutdown command, the init daemon starts processes by reading information from the /etc/inittab file. This file defines these important items for the init process:

• That the init process will restart

• What processes to start, monitor, and restart if they terminate

• What actions to take when the system enters a new run level

Each entry in the /etc/inittab file has the following fields:

id:rstate:action:process

The following table describes the fields in an inittab entry.

Table 1-4 Fields Descriptions for the inittab File

Example 1-2 Default inittab File

The following example shows a default inittab file that is installed with the release. A description for each line of output in this example follows.

ap::sysinit:/usr/sbin/autopush -f /etc/iu.ap  (1)
smf::sysinit:/lib/svc/bin/svc.startd    >/dev/msglog 2<>/dev/msglog </dev/console      (2)
p3:s1234:powerfail:/usr/sbin/shutdown -y -i5 -g0 >/dev/msglog 2<>/dev/...(3)

1. Initializes STREAMS modules

2. Initializes the master restarter for SMF

3. Describes a power fail shutdown

What Happens When the System Is Brought to Run Level 3

1. The init process is started and reads the properties that are defined in the svc:/system/environment:init SMF service to set any environment variables.

2. The init process reads the inittab file and does the following:

   1. Executes any process entries that have sysinit in the action field so that any special initializations can take place before users login

   2. Passes the startup activities to svc.startd

   For a detailed description of how the init process uses the inittab file, see the init(1M) man page.