Ubuntu – find the SUDO_COMMAND environment variable

command linesudo

I'm currently learning the foundations of Linux with Ubuntu and there is a little activity where I need to find information about environment variables. I already found 6/7 info but just can't find SUDO_COMMAND. this is how the list goes:

SHELL=/bin/bash
USER=student
SUDO_COMMAND=
PWD=/home
HOME=/home/student
LOGNAME=student
OLDPWD=/home/student

I noticed that the information comes in order and the SUDO_COMMAND is between user and pwd. did I make a mistake somewhere?

Best Answer

SUDO_COMMAND is an environment variable set by sudo only in the environment of the process started by it (and inherited by any child processes). If you run sudo some-command arg1 arg2, then SUDO_COMMAND will contain the absolute path to some-command, and arg1 arg2. If you ran sudo -s or sudo -i, then the variable will be set to the shell that was started. In any case, you probably won't see it outside of a process tree started by sudo.

For example:

$ sudo sh -c 'echo $SUDO_COMMAND'
/bin/sh -c echo $SUDO_COMMAND

Or:

$ sudo env
HOME=/home/muru
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin
TERM=xterm-256color
LANG=en_US.UTF-8
LC_NUMERIC=en_GB.UTF-8
LC_TIME=en_GB.UTF-8
LC_MONETARY=en_GB.UTF-8
LC_PAPER=en_GB.UTF-8
LC_NAME=en_GB.UTF-8
LC_ADDRESS=en_GB.UTF-8
LC_TELEPHONE=en_GB.UTF-8
LC_MEASUREMENT=en_GB.UTF-8
LC_IDENTIFICATION=en_GB.UTF-8
MAIL=/var/mail/root
LOGNAME=root
USER=root
USERNAME=root
SHELL=/bin/bash
SUDO_COMMAND=/usr/bin/env
SUDO_USER=muru
SUDO_UID=1000
SUDO_GID=1000

I noticed that the information comes in order

I don't know which command you're using, but you cannot rely on the output of set, declare, env or printenv to be in some order.

Related Question