Installation guide

3.3.2 Overriding Boot Commands
The previous section described how to set the boot commands. This section
describes how to override those commands.
• Overriding bootdef_dev
To override the bootdef_dev variable, supply the desired boot device
as an argument to the boot command. For example, if your boot device is
set to boot from disk dka0 and you want to boot from disk dkb0, enter:
>>> b dkb0
• Overriding boot_osflags
The boot_osflags variables are ignored if you specify the −fl option
to the boot command, as follows:
>>> b -fl
To override the boot_osflags variables, pass the desired choices to
the −fl option. For example, the following command boots to the
interactive prompt so you can specify an alternate kernel, and then
boots to multiuser mode:
>>> b -fl ai
• Overriding boot_file
To boot a kernel other than that specified by boot_file, enter the boot
command with the following syntax:
b-fi kernel
For example, to boot the genvmunix kernel, enter:
>>> b -fi genvmunix
3.4 Identifying System Run Levels
A run level (mode) specifies the state of the system and defines which
processes are allowed to run at that state. There are four basic run levels
available, as follows:
0
Specifies the halt state
S or s
Specifies single-user mode
2
Specifies multiuser mode without network services
3
Specifies multiuser mode with network services
Specifies the console mode
The inittab file contains line entries that define the specific run levels
and the run command scripts that are associated with the run level. When
3–10 Starting Up and Shutting Down the System