Bash script to verify the daemon is working if not, start the daemon

kishoreru · 09-22-2009, 02:29 PM

Hi,
I need to write a bash script to verify some xyz daemon is running are not, if not start that xyz daemon

Any help would be appreciated...

Thanks is Advance

nuwen52 · 09-22-2009, 03:12 PM

A lot of daemons store their process ID in a file in /var/run (ex. sshd.pid for the sshd daemon). You might try looking there. Then if you find it, you can do an 'if [ -x "/proc/<PID>" ]' to see if the process directory exists. Otherwise, just a grep through a "ps -ax" for the daemon name might be enough.

catkin · 09-22-2009, 03:28 PM

If the xyz daemon init script is fully featured then the commands you need are

Code:

/etc/init.d/xyz status

and

Code:

/etc/init.d/xyz start

or maybe restart would be safer -- cleaning up after a crashed daemon. You can find out more by inspecting the /etc/init.d/xyz script.

lwasserm · 09-22-2009, 04:41 PM

You might take a look at the "start-stop-daemon" program that is used in debian and possibly other distros.

unSpawn · 09-22-2009, 05:11 PM

Quote:

Originally Posted by kishoreru

I need to write a bash script to verify some xyz daemon is running are not, if not start that xyz daemon

If "need to write" is not due to some class assignment then unless you're into reinventing the wheel I'd look at something like Monit instead. It'll be faster than interpreted code, more configurable than you can script in one month and it's used, supported, maintained OSS.

lutusp · 09-22-2009, 08:25 PM

Quote:

Originally Posted by kishoreru

Hi,
I need to write a bash script to verify some xyz daemon is running are not, if not start that xyz daemon

Any help would be appreciated...

Thanks is Advance

This is just a hint, not a complete solution (because your question sounds like homework).

Code:

# service httpd status | grep -iqP "\brunning\b" && (do something here)

kishoreru · 09-23-2009, 12:52 AM

Quote:

Originally Posted by lutusp

This is just a hint, not a complete solution (because your question sounds like homework).

Code:

# service httpd status | grep -iqP "\brunning\b" && (do something here)

Thanks lutusp & All

I am new to Linux and Bash may be my question sounds like a homework :-)

tikit · 09-23-2009, 05:29 AM

You can use init to control the service. Put this line to /etc/inittab

Code:

ap:2345:respawn:/usr/sbin/apache2

and reload the init process

Code:

kill -HUP 1

If the service stops in will be automatically started