Running a Command as Another User

Brandon9000 · 08-02-2012, 01:21 PM

I need to have a program run as root issue a command as a non-root user. It could be any command whatsoever. I am trying to make sudo do this, but I can't seem to make it behave exactly like the specified user. Testing from the command line:

$ sudo -i -u GWashington env | grep HOME
$ HOME=/home/GWashington

but:

$ sudo -i -u GWashington echo $HOME
/root

How can I use sudo (or anything) to enable root to behave more like the specified user?

Thanks in advance.

Didier Spaier · 08-02-2012, 01:34 PM

I would use "su - other_user".

Roken · 08-02-2012, 01:44 PM

I have a script started as a normal user at boot using:

Code:

/usr/bin/sudo -u user -n -i command

which works just fine.

Brandon9000 · 08-02-2012, 01:46 PM

Thanks, Didier. I would too, but it is my understanding that su isn't universal or at least that the syntax is distribution dependent, and this has to work on as many distributions as possible, and with the very same syntax. Isn't there a problem with su on Ubuntu?

Brandon9000 · 08-02-2012, 01:51 PM

Quote:

Originally Posted by Roken

I have a script started as a normal user at boot using:

Code:

/usr/bin/sudo -u user -n -i command

which works just fine.

Perhaps it will, but it doesn't seem to receive the user's whole environment, as I show above, and I can count on my users to issue every conceivable command with it. I just wondered if there were something more I could do.

Roken · 08-02-2012, 01:52 PM

I wonder if your problem is because the root user will launch the user command as a child process, and env is picking up $HOME from the parent process. If you wrap env | grep HOME and HOME= in a bash script, and then launch that using sudo -u does it return the correct result?

Brandon9000 · 08-02-2012, 01:54 PM

Quote:

Originally Posted by Roken

I wonder if your problem is because the root user will launch the user command as a child process, and env is picking up $HOME from the parent process. If you wrap env | grep HOME and HOME= in a bash script, and then launch that using sudo -u does it return the correct result?

I put the command in a script and it still came up with "/root."

Edit - I'm wrong. Doing exactly what you say, it comes up with "/home/GWashington."

Roken · 08-02-2012, 01:59 PM

Then my work here is done

Glad it worked.

Brandon9000 · 08-02-2012, 02:02 PM

This is very helpful. Of course, to make this work, my program would have to spit out a temp bash script, run it with sudo -u, and then delete it. That is certainly possible, and there are probably no negative consequences, although it would be nice if I could do it in some way without creating temp files. I hate to seem ungrateful and this will certainly work.

ntubski · 08-03-2012, 09:26 AM

Quote:

Originally Posted by Brandon9000

it is my understanding that su isn't universal or at least that the syntax is distribution dependent, and this has to work on as many distributions as possible, and with the very same syntax. Isn't there a problem with su on Ubuntu?

I think su is more universal than sudo: su is in coreutils. Ubuntu doesn't give root a password so you can't su to root, however since you are suing from root this isn't a problem for you.

Brandon9000 · 08-03-2012, 09:28 AM

Okay. That makes sense.

XavierP · 08-06-2012, 04:17 PM

Moved: This thread is more suitable in Programming and has been moved accordingly to help your thread/question get the exposure it deserves.

suicidaleggroll · 08-06-2012, 04:41 PM

Quote:

Originally Posted by ntubski

I think su is more universal than sudo: su is in coreutils. Ubuntu doesn't give root a password so you can't su to root, however since you are suing from root this isn't a problem for you.

I agree

su is everywhere, even on embedded systems. sudo is a bit more flaky.