Running a shell script continuously after exiting the login session

[Shivkumar]

Dear Sir,

i am runnig a shell script test1.sh and recording its out in a file test2. I used the command $./test1.sh >>test2 &

But when i exited xterm session (login session) the script stopped. I wanted to run it continuously even if i logged out. How to do it ?

Thanks,
Shiv

[Joseph Loo]

hi,

because u r running it off as a job at the background, either u do not exit/logoff or setup as a cron job.

regards.

[Jeff_Traigle · Accepted solution]

You need to use nohup:

nohup command $./test1.sh >>test2 &

This will create a nohup.out file in the directory you execute it in.

[Senthil Prabu.S_1]

Hi Shiva,
use nohup. It will continue to operate, even when u close your session. It will send the output to the file name nohup.out. Even you can specify your own file, where the output can be stored.

EX:
nohup test1.sh &


HTH,
Prabu.S

[Arunvijai_4]

Hi Shiv,

"nohup" is the command that will help you.
nohup - run a command immune to hangups

You can run as,

$ nohup ./test1.sh >>test2 &

-Arun

[Muthukumar_5]

When you start a script it will take the shell base process ID will the uppper level Parent Process ID.

You can avoid that by starting with su as,

# su - -c "/test1.sh 1>/tmp/test1.log 2>&1 &"

Example:
# cat /tmp/muthu/test1.sh
echo "script is started"
sleep 10
echo "script is end"
hostname
ls -l
# su - root -c "/tmp/muthu/test1.sh 1>/tmp/muthu/test.log 2>&1 &"

it is working after log out too.

--
Muthu

[Arunvijai_4]

Shiv, "nohup" is better way of executing your shell scripts. You dont need to "su" and execute it.

You can see more information at,

http://www.computerhope.com/unix/unohup.htm
http://www.livefirelabs.com/unix_tip_trick_shell_script/june_2003/06022003.htm

-Arun

[Muthukumar_5]

we can use su too. Don't worry. Try to find whether solution is working or not ;)

nohup is another way to achive it. It is like it will execute the process until it is getting completed.

Su is like it will create another process which will not be controlled by currently logged shell.

--
Muthu

[Senthil Prabu.S_1]

Muthu,

And it is not advised to use "SU" while running a script. It may lead to a security lapse..:-)


--
Prabu.S

[Arunvijai_4]

I would say, "nohup" is the primay way. If it doesn't help you by any changes, you can go for "su". But, remember this is a big security hole in a production environment and could lead to hazards. Secuirty is the prime in today's world .

-Arun

[Muthukumar_5]

prabhu,

If you are running as a same user then it is not a problem to do right? :)

Like

user -> su to same user.

It is a thought to reach the destination. Dream yourself to get more ways. Don't using same way always ;)

==

Shiv,

Simple way is to use nohup. You can go with su or as well as telnet + piping() program too.

--
Muthu

[Arturo Galbiati]

Hi Shiv,
you have to use nohup:
nohup ./test1.sh >>test2 2>&1 &

I suggest you to redircet the stderr (2) to the stdout (1) otherwise you will find it in the nohup.out file.

HTH,
Art

[Steve Andrews_6]

Hi Shiv:

I would also use the fully qualified path when using nohup.
$nohup /dir/dir/test1.sh >>test2 2>&1 &