Identify user in a Bash script called by sudo

linux bash sudo
quadmore picture quadmore · Aug 19, 2010 · Viewed 51.4k times · Source

If I create the script /root/bin/whoami.sh containing:

#!/bin/bash
whoami

and this script is called by a user with a properly configured sudo, it will indicate

root

Is there a fast way to obtain the actual user in a script, or will I have to resort to parameters passing along this username?

Answer

evan picture evan · Jan 4, 2011

$SUDO_USER doesn't work if you are using sudo su -.
It also requires multiple checks - if $USER == 'root' then get $SUDO_USER.

Instead of the command whoami use who am i. This runs the who command filtered for the current session. It gives you more info than you need. So, do this to get just the user: 

who am i | awk '{print $1}'

Alternatively (and simpler) you can use logname. It does the same thing as the above statement.

This gives you the username that logged in to the session.

These work regardless of sudo or sudo su [whatever]. It also works regardless of how many times su and sudo are called.

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