running su from a bash script

caminoix · 12-27-2005, 02:48 PM

hello

i'd like to write a script that would perform something as root but could be run by any user.
i've tried simply putting "su" into it but the script exits immediatel after i enter the password. "sudo" says i don't have the permission required.
how can i prompt for the root password, execute a root-only command and come back to the normal user from inside one script?

Hko · 12-27-2005, 03:17 PM

Use the "-c" option with "su" to run a command as root. See "man su".

The script below runs "whoami" three times. First as a normal user, then asks for root password, and runs "whoami" as root. And finally it runs "whoami" as the normal user again.

Code:

#!/bin/bash

whoami
su -c whoami
whoami

acid_kewpie · 12-27-2005, 03:18 PM

use sudo, that's what it's there for.. just read up on sudo and /etc/sudoers and you'll be a lot happier...

caminoix · 12-27-2005, 06:14 PM

i've tried reading man but must have either missed or misunderstood this part.

thank you

bigearsbilly · 12-28-2005, 05:08 AM

google: sudo sudoers

Hko · 12-28-2005, 06:14 AM

Quote:

Originally Posted by caminoix

i've tried reading man but must have either missed or misunderstood this part.

Just type "man su" (without those double quotes) in a terminal, and you will see su's manual, where you can read how to use su, what command line options it takes, etc..

Very useful.

caminoix · 12-28-2005, 06:33 AM

erm, this is what i did and still failed to find the answer... but thanks anyway

carl.waldbieser · 12-28-2005, 03:41 PM

Quote:

Originally Posted by caminoix

i've tried reading man but must have either missed or misunderstood this part.

thank you

One of the things you can configure sudo to do is to let a particular user or users run a particular command or commands as root. So the idea would be to do something like configure the /etc/sudoers file so that anyone you ran your command could do so as root.

I don't recall the exact syntax for the file, but as others have pointed out, it is in the man pages, on search engines, etc. One thing to be aware of is that it is typically advisable to edit the /etc/sudoers file with the "visudo" command.