System Administration Guide: Basic Administration

/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:

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


The following table describes the fields in an inittab entry.

Table 18–4 Fields Descriptions for the inittab File




Is a unique identifier for the entry. 


Lists the run levels to which this entry applies. 


Identifies how the process that is specified in the process field is to be run. Possible values include: sysinit, boot, bootwait, wait, and respawn.

For a description of the other action keywords, see inittab(4).


Defines the command or script to execute. 

Example 18–2 Default inittab File

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

ap::sysinit:/sbin/autopush -f /etc/iu.ap  (1)
sp::sysinit:/sbin/soconfig -f /etc/sock2path             (2)
smf::sysinit:/lib/svc/bin/svc.startd    >/dev/msglog 2<>/dev/msglog      (3)
p3:s1234:powerfail:/usr/sbin/shutdown -y -i5 -g0 >/dev/msglog 2<>/dev/...(4)
  1. Initializes STREAMS modules

  2. Configures socket transport providers

  3. Initializes the master restarter for SMF

  4. 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 /etc/default/init file to set any environment variables. By default, only the TIMEZONE variable is set.

    1. Then, init reads the inittab file and does the following:

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

    3. Passes the startup activities to svc.startd.

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