System information

An Introduction to Shells in General
Axis Communications AB provides NO support for application development of any kind. The information
here is provided "as is", and there is no guarantee that any of the examples shown will work in your
particular application.
Revision 1.02 October 2002 51
tty2::askfirst:/bin/sh
tty3::askfirst:/bin/sh
tty4::askfirst:/bin/sh
If you choose to use an /etc/inittab file, the inittab entry format is as follows:
<id>:<runlevels>:<action>:<process>
<id>:
WARNING!
This field has a non-traditional meaning for BusyBox init! The id field is used by BusyBox init
to specify the controlling tty for the specified process to run on. The contents of this field are
appended to "/dev/" and used as-is. There is no need for this field to be unique, although if it
isn't you may have strange results. If this field is left blank, the controlling tty is set to the
console. Also note that if BusyBox detects that a serial console is in use, then only entries whose
controlling tty is either the serial console or /dev/null will be run. BusyBox init does
nothing with
utmp. We don't need a utmp.
<runlevels>:
The runlevels field is completely ignored.
<action>:
Valid actions include: sysinit, respawn, askfirst, wait, once,
ctrlaltdel, and shutdown
.
The available actions can be classified into two groups: actions that are run only once,
and actions that are re-run when the specified process exits.
Run only-once actions:
sysinit is the first item run on boot. init waits until all sysinit actions are
completed before continuing. Following the completion of all sysinit actions, all wait
actions are run.
'
wait' actions, such as sysinit actions, cause init to wait until the specified task
completes. 'once' actions are asyncronous, therefore,
init does not wait for them to
complete. 'ctrlaltdel' actions are run when the system detects that someone on the
system console has pressed the CTRL-ALT-DEL key combination. Typically one wants
to run 'reboot' at this point to cause the system to reboot. Finally the 'shutdown'
action specifies the actions to be taken when init is told to reboot. Unmounting
filesystems and disabling swap is a very good here.
Run repeatedly actions:
'respawn' actions are run after the 'once' actions. When a process started with a
'respawn' action exits, init automatically restarts it. Unlike sysvinit, BusyBox
init does not stop processes from respawning out of control. The 'askfirst' actions
act just like respawn, except that before running the specified process it displays the line
"Please press Enter to activate this console" and then waits for the user
to press enter before starting the specified process.