Writing a startup script(OpenWrt)

Writing a startup script

The boot process may be customized to add new daemons, provide alternate ways of starting existing daemons, or otherwise do things at startup and shutdown.

This, is /etc/init.d/example. As written it supports all standard options, e.g, 'restart', 'enable', etc. as well as 'start' and 'stop'.:

#!/bin/sh /etc/rc.common # Example script # Copyright (C) 2007 OpenWrt.org  START=10 STOP=15  start() {         echo start         # commands to launch application }  stop() {         echo stop         # commands to kill application } 

After creating it, run

chmod a+x /etc/init.d/example

to make it executable. Then run

/etc/init.d/example enable

, this creates a link to the script in the

/etc/rc.d/

directory. The

START=10

means that this will become

/etc/init.d/S10example

- the 10 signifies the order the script is to be executed, allowing it to be placed before or after existing scripts. The

STOP=15

is optional and will create a

/etc/rc.d/K15example

.

On startup, all the scripts matching the pattern /etc/rc,d/S* are executed in the form of ” boot”, which will run the commands in the start() section. On shutdown the /etc/rc.d/K* scripts are executed as ” stop” causing the stop() section to be run.

Here's a few commands to illustrate the use -

/etc/init.d/example /etc/init.d/example enable /etc/init.d/example boot /etc/init.d/example start /etc/init.d/example restart /etc/init.d/example stop /etc/init.d/example disable 

Additionally, you can define a boot() section -

boot() {         echo boot         # commands to run at boot          # continue with the start() section         start  } 

Now, running the script with the boot argument will trigger the boot() section (which then triggers the start section). This allows you to run additional commands at bootup, avoiding them on the restart command.

Custom functions in init scripts

/etc/init.d/example

#!/bin/sh /etc/rc.common # Example script # Copyright (C) 2007 OpenWrt.org  START=10 STOP=15  EXTRA_COMMANDS="custom" EXTRA_HELP="        custom  HELP text for custom"  start() {         echo start         # commands to launch application }  stop() {         echo stop         # commands to kill application }  custom()  {         echo custom function         # do something } 

root@OpenWrt:/# /etc/init.d/example Syntax: /etc/init.d/example [command]  Available commands:         start   Start the service         stop    Stop the service         restart Restart the service         reload  Reload configuration files (or restart if that fails)         enable  Enable service autostart         disable Disable service autostart         custom  HELP text for custom root@OpenWrt:/etc/init.d# 

root@OpenWrt:/# /etc/init.d/example custom custom function root@OpenWrt:/#