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mahatmanich
Asked: 2016-03-27 16:04:45 +0800 CST

printing user of subshell obtaining root via su -

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Can I print the username which is obtaining root access via su - on the root console upon obtaining root?

user1$ su -
password:

obtained root via user1
#
linux

2 Answers

  1. Best Answer

    Previously I recommend the script below... I found a better way! :) Just exec:

    logname

    Also, you can use $SUDO_USER, but doesn't work if you are using sudo su -
    By the way, who am i is like who -m

    This script also does the work:

    #!/bin/bash
curpid=`awk '/^PPid:/{print $2}' /proc/$BASHPID/status`
ppui=`awk '/^PPid:/{print $2}' /proc/$curpid/status`
ppui=`awk '/^PPid:/{print $2}' /proc/$ppui/status`
uid=`awk '/^Uid:/{print $2}' /proc/$ppui/status`
name=`cat /etc/passwd | grep $uid | awk -F: '{print $1}'`
echo $name

    Call it through .bash_profile if you are using login shells or .bashrc if using interactive non-login shells.

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  2. who am i|awk '{print "Obtained root via "$1}'

    Add it to root's .bashrc to execute when you su.

    You can also try

    pstree -p -u |grep "$$"

    to see the whole chain of processes with usernames. This could be useful if you have nested su with multiple users.

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