Running Commands at Startup in Debian and Ubuntu – The Simplest Approach
By Austin White
Running custom scripts on startup is a common operation in the Linux community. In my case, when the machine hosting my website needs to be rebooted or even crashes, it is critical that the backend processes that the website depends on start correctly. For other Linux or BSD users, it can be useful to start up useful background processes, perhaps servers for accessing your machine remotely.
The Classic Method for Running Processes at Startup
The most documented way of starting processes when the machine boots is to add a control script to /etc/init.d. This script must take an argument that can be one of “stop,” “start,” and “restart.” An example of such a script would be /etc/init.d/ssh, which is used to start and stop the ssh server. When a machine shuts down, it is important for many daemons to clean up their pid files and otherwise shut down nicely. However, for user-run processes, simply being sent SIGTERM as part of normal shutdown is sufficient.
Here is an example of a script that is used only for starting a process.
$ cat /etc/init.d/boot_server
#!/bin/sh -e
case "$1" in
start)
/home/prod/start_server.sh
;;
stop)
;;
reload|restart|force-reload)
/home/prod/start_server.sh
;;
*)
echo "Usage: [this] {start|stop|restart|reload|force-reload}" >&2
exit 1
;;
esac
exit 0
To ensure that daemons are started and stopped, particularly in the correct order, the machine runs special symlinks to these scripts. The symlinks have special names that either begin with an S or a K. For example, my machine has /etc/rc3.d/S20lighttpd and /etc/rc0.d/K20lighttpd. (The numbers in the rc directory names are known as runlevels. A discussion of runlevels is beyond the scope of this article, and if you wish to know more, there are a number of good resources on the internet.) Scripts beginning with S are used to start a process during bootup. Those beginning with K are used to kill a process during shutdown. The number in the link name is used to determine the order in which these processes are started and killed.
Thus, to run a process at startup on your Linux machine, you would need to both add a script to /etc/init.d that takes “start” as an argument, and you would want to add symlinks to your script to the /etc/rc*.d directories. Your scripts have to follow the naming convention described above, probably starting with S99 or S98 to ensure that your processes start after all the important system daemons. The K symlink is unnecessary.
Using /etc/rc.local – A Better Way to Start Processes on Debian and Ubuntu
Instead of adding a startup script and the related symlinks, a much easier approach is to add your commands to the bash script /etc/rc.local. A quick look at /etc/rc.local demonstrates that it is rather self-explanatory.
$ cat /etc/rc.local #!/bin/sh -e # # rc.local # # This script is executed at the end of each multiuser runlevel. # Make sure that the script will "exit 0" on success or any other # value on error. # # In order to enable or disable this script just change the execution # bits. # # By default this script does nothing. exit 0
At the end of /etc/rc.local, but before the exit 0 line, I can simply add a call to my server startup script:
# Run website processes /home/prod/start_server.sh
It is a one-line change, instead of adding an overly complicated script and the related symlinks. Of course, this is not an option if you require additional commands to be run at shutdown. In addition, if you need your process to be started before some other system process, you must resort to the classic startup script as discussed above. /etc/rc.local almost the last script to be run as part of the boot process.
Conclusion: Use /etc/rc.local to Run Processes at Startup in Linux
Classic startup scripts in /etc/init.d and /etc/rc*.d are appropriate for many daemons and some more complicated user processes that must either start before a system process or be cleaned up during shutdown. However, /etc/rc.local is preferred for all other cases. It is a simple bash script you can edit as root on your machine.
Austin is a software engineer working on askR.com, a social recommendations site.
A few years earlier I had experimented with RedHat Linux but had no real success with it as it had problems detecting my usb keyboard and mouse. Which was obviously a bit of a non-starter for me. I knew that big advances were being made in the Linux world so I decided to do a bit of research.
I downloaded the ISO of Ubuntu Linux from the Ubuntu website 
After playing around in Ubuntu’s environment for a bit you’ll notice an examples folder on the desktop that has various types of files that can be opened using Ubuntu’s default programs installed. For example, Ubuntu will use Open Office (a free alternative to Microsoft Office) to open DOC files.
Setting your system with english locales, so that your desktop, menus and programs’ file menus won’t show english characters in blurry chinese ttf fonts. You will still have the ability to input chinese in almost everything(browsers, konquerer, instant messengers, konsole, xchat and more).
