How to execute a shell script on startup?
Solution 1:
/etc/init.d
is the script directory, in which the executable scripts appear. However, in order to run scripts in a particular order after your system starts, you need to add files to the /etc/rc#.d
directory. Entries that appear here tell your system in what order and at what run level scripts in /etc/init.d
should be run. The number after the rc indicates what run level the machine is running at, according to this chart:
http://en.wikipedia.org/wiki/Runlevel
So if you have:
/etc/init.d/importantscript
Then you need the (empty) files:
/etc/rc.d/rc3.d/S20importantscript
/etc/rc.d/rc6.d/K20importantscript
The S means start, and the K means kill. When your machine starts, the system will say "Ah, I'm running at RunLevel 3, let's pop over to rc3.d to see what scripts in '/etc/init.d' need to be run and in what order." In this case, the system will sort by 'S' and then the number after 'S' and will execute '/etc/init.d/importantscript start'. The 20 is just for ordering purposes... your script will run behind 'S19' and in front of 'S21'. You can create these files simply by doing:
sudo touch /etc/rc.d/rc3.d/S20importantscript
Here's a nice summary as well: http://www.linux.com/news/enterprise/systems-management/8116-an-introduction-to-services-runlevels-and-rcd-scripts
Solution 2:
You don't have to --- and shouldn't --- create files in /etc/rc.d/rcN.d/
; what you should do instead is put a comment in your init script reading
# chkconfig NNN A B
where NNN
is the set of run-levels in which you want the script active (e.g., 345
if it's active in runlevels 3
, 4
, and 5
), and A
and B
are the start and stop priorities. Then chkconfig --add foo
(assuming your script is named foo
) will create the files in /etc/rc.d/rcN.d/
with the appropriate names.
You can then use service foo bar
to send the bar
message to your script (e.g., start
, stop
, whatever -- that's where your $1
comes from).