How to turn off the system automatically ?

gardenair · Post by **gardenair** » Mon Mar 14, 2011 11:14 am

Hi,
I am using Cent Os 5. I want that the system should shutdown automatically at 7:00 pm daily and next day I manually turn on the system.I have google it but the syntax is not clear.

I use
# crontab -e
and write the command
0 19 * * * /sbin/shutdown -h now

I does't apply the command but please guide me that what is * * * after 19
Kindly guide me how can I enable this feature? and If i want to shutdown the system at 7:30 PM then how will it write ?
thanks in advance,
garden

Kamran.Ahmed · Post by **Kamran.Ahmed** » Mon Mar 14, 2011 11:53 am

use cron scheduler

type at shell crontab -e it will open vi editor then type below command

0 19 * * * /sbin/shutdown -h now

this cron command shutdown system at 7:00 pm daily

gardenair · Post by **gardenair** » Mon Mar 14, 2011 11:59 am

thanks kamran bhai for the reply. Well what does * * * means ?
If I want to change the time 7:00 pm to 7:30 pm then it will be as

0 19 30 00 /sbin/shutdown -h now

Kamran.Ahmed · Post by **Kamran.Ahmed** » Mon Mar 14, 2011 12:08 pm

in case you want to shutdown at 7:30 then command will be

0 19:30 * * * /sbin/shutdown -h now

i suggest kindly read man pages of the following

crond, crontab

man crond
man crontab

for more information and syntax

gardenair · Post by **gardenair** » Mon Mar 14, 2011 12:17 pm

thanks a lot for the reply.Actually In my Linux box squid is already running so before shutting down the system how can I stop squid service and then the system may shutdown with the crontab ?
Is this method will also stop squid service as well ?
thanks again for your valuable guidance,
garden

Kamran.Ahmed · Post by **Kamran.Ahmed** » Mon Mar 14, 2011 2:05 pm

Dear you seems to me new to linux

shutdown command is full flagged command it is stopped all running services (deamons) properly then shutdown the system there is no need to stop squid etc if you apply without cron then issue

shutdown now

and if u stop squid manually

service squid stop

gardenair · Post by **gardenair** » Mon Mar 14, 2011 2:46 pm

thanks again for the reply. well I am not an expert in Linux but i am working on it each day.I have configured squid in my office and it is functional. Each day I discover new thing and it is helping me a lot for improving my linux in Linux.
Well I have also studies the man pages and it is wonderfull and have lot of things inside it. Well I have also tried with
0 14:30 * * * /sbin/shutdown -h now
but unfortunately it does not shutdown the system. Any idea thing missing I think

Kamran.Ahmed · Post by **Kamran.Ahmed** » Mon Mar 14, 2011 2:59 pm

it will working as a cron job and i must be as below

30 14 * * * /sbin/shutdown -h now

study RHCE guide by Michele Jang it is awesome

Kamran.Ahmed · Post by **Kamran.Ahmed** » Mon Mar 14, 2011 3:06 pm

ohh i am sorry if you want to shutdown at 14:30 then command will be

30 14 * * * /sbin/shutdown -h now

kindly look into the syntax

# m h dom mon dow command

gardenair · Post by **gardenair** » Mon Mar 14, 2011 4:50 pm

thanks a lot Kamran bhai for your kind help and giving time for helping me. kindly check pm.