want to use su within cron to run as another user

[Gregory Locke]

I have one job that needs to run in cron as another user. I don't want to create another crontab for this one shot program.

The generic user login is notrig (home/notrig)

My syntax for crontab is:
30 01 01 * * /usr/bin/su - notrig /home/notrig/program >/tmp/notrig.program.out 2>&1

Any suggestions?

[Patrick Wallek · Accepted solution]

You need to add a '-c' to your command line.

30 01 01 * * /usr/bin/su - notrig -c /home/notrig/program >/tmp/notrig.program.out 2>&1


For more details see the su man page.

[James R. Ferguson]

Hi Gregory:

Since you are going to cause your '.profile' to be sourced (read), you should modify your '.profile' to only conditionally execute its terminal-handling logic --- the 'stty' and 'tset' commands --- when the process is associated with a terminal. This will eliminate the annoying "not a typewriter" output you will otherwise get.

To test if your process is associated with a terminal, you can do (for the purposes here):

if [ -t 0 ]; then
...
fi

...When the above is true, the process is associated with a terminal and it is "safe" to execute 'stty' and 'tset' commands.

Regards!

...JRF...

[Gregory Locke]

Patrick:

Where did you find that -c option?

I didn't see it in any of the man pages.

[Ivan Krastev]

From man page - http://docs.hp.com/en/B2355-60103/su.1.html

"Execute the command, 'echo hello', using the temporary environment and permissions of user bin. In this example, user bin's shell is invoked with the arguments -c 'echo hello'.

su bin -c 'echo hello'
"

-c is argument to shell, not to su.


regards,
ivan

[Gregory Locke]

Thanks Patrick, James and & Ivan for your help.

[Gregory Locke]

James:

Where in a .profile would I place

if [ -t 0 ]; then
...
fi

to keep from getting errors like
more infx.ccnotice.out
ttytype: couldn't open /dev/tty for reading
stty: : Not a typewriter
Not a terminal
stty: : Not a typewriter
stty: : Not a typewriter
^[2 ^[2 ^[2 ^[2 ^[2 ^[2 ^[2 ^[2
^[2 ^[2 ^[2 ^[2 ^[2 ^[2 ^[2 ^[2 ^[2 ^[2
^[2 ^[2
stty: : Not a typewriter