[QUOTE=s&j;107336]
I have a program that I want to run as a service on my linux machine i.e. it should always be executing. After a system reboot it should start running automatically without any user intervention.

I was thinking of using cron to somehow schedule the program to launch after every reboot but I am not sure if that what I should be using.


We can also use crontab to run a job after system reboot.

Just make an entry in the cron as follows:

@reboot <yourscript.sh>

-Bz

Wow talk about bringing a post back from the dead, hopefully he figured it out after 8 years . Well since I was notified I might as well add some more now to this dated post. It looks as SysV is going to be finally be replaced in the next few years. Ubuntu has already gone that way by moving to upstart.

http://upstart.ubuntu.com/

Also if you just want your program or some script to start and you don't want to fuss with run level stuff just use /etc/rc.local

Lastly if you don't need the app to start until you logon to your gnome session in distro's like the latest Ubuntu (10.04) just use the gui session startup

System -> Setup -> Startup Applications


A few more cron special commands

@reboot Run once, at startup.
@yearly Run once a year, "0 0 1 1 *".
@annually (same as @yearly)
@monthly Run once a month, "0 0 1 * *".
@weekly Run once a week, "0 0 * * 0".
@daily Run once a day, "0 0 * * *".
@midnight (same as @daily)
@hourly Run once an hour, "0 * * * *".

will there be any problem if we give the path of the service in /etc/rc.local? ( /etc/rc.d/rc.local in few distros)
I mean. Is it the preferred way? if not, what is the preferred one.

Pretty much always use full paths (it never hurts) and if you want to make it a bit more portable just make the paths variables so they can easily be changed. rc.local is kind of like the junk drawer made to catch situations like this so not much for standards. You can use it to call other scripts or write the script directly in the file. If you wanted to make a more standard approach make your own /etc/init.d startup script and then use something like update-rc.d to turn it on or off.