UNIX for Dummies Questions & Answers

I have a script in which I need to login as another user, using the

su command



What is the syntax/format for this command which allows me to input the password along with the command name and userid, all at the same time?

Something like:


su newuserid ????????

(where ???????? is where I'm hoping to input the password for "newuserid")

Can I input this in my script, all on one line so that I'm not prompted for the password, as step #2 of the "su" command processing?

my `man su` says its not possible to give password to su command as a command line parameter. i tried "echo 'pass' | su ...", but it`s not work too.

I don't believe you can su to a user in a script.
you want to sudo the command as the desired user and set the command up with permissions in your sudoers file.

ie your sudoers file says that user jack has permission to execute command lpc as user jill.

in your script you would run it from user jack and sudo lpc which would make it look like you are executing it as jill.



The man pages show how to set this up.

Remember, I posted this in the Unix for Dummies section

Could you give me a "real basic" example of exactly what you are suggesting? (kind of a "step by step" cookbook approach)?

I'll be forever in your debt

Thanks!

In its most basic form, sudoers looks like this:
# sudoers file.
#This file MUST be edited with the 'visudo' command as root.
#See the man page for the details on how to write a sudoers file.
#
# Host alias specification
Host_Alias PROD=MyBigFatServer

Defaults logfile=/var/log/sudo.log

# User alias specification
# JACK - Jack

User_Alias FETCHING=JACK

# Cmnd alias specification
Cmnd_Alias DO_FETCHING=/bin/GetaPailofWater

# User privilege specification
FETCHING = NOPASSWD:DO_FETCHING

This means that Jack can execute the command GetaPailofWater as root with no password by typing the following at the command line.

# sudo GetaPailofWater

You can put this in a script in the same format.

The sudo log will show this as JACK performing the command as root.
If your audit process will not let you do this (this command HAS to be executed as JILL) there is a way to say that JACK can to this command as JILL by adding the runas alias and -u JILL on the command. We had difficulty getting this to work on our older servers, so we don't use it. The example above meets our audit requirements and allows JACK to do his thing.