How to get variable environment from parent user?

antonio1

11/2/22, 9:12 PM

I need to know how it's possible to get environment variable from a parent user after su? For example if I'm evan user and I have variable $DISPLAY=:10.0, then I use "su -" to go to root user, how could I get the $DISPLAY variable from parent evan user?

2 + 2

environment

kanehekili

11/2/22, 9:20 PM

Looks like a XY [problem](https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem). Might tell us, why you need the display in root...

antonio1

11/2/22, 9:26 PM

very well. I need to su in root to run a script, but later in script I have to launch xclock which is not working because something like display problem is not inherited from original user. If I set manually the DISPLAY as original user evan, everything works nice, but the display value is changing.

Score:0

Ubuntu

kanehekili

11/2/22, 10:03 PM

In this case I'd look at xhost

Usually I could also manage to get some GUI open as root (depending on the linux distro) with defining

export DISPLAY=:0.0

in my script.

That the display id is changing as you have written is unknown to me.

0 + 1

antonio1

11/2/22, 10:19 PM

as soon as the DISPLAY is different than original opened one DISPLAY=:10.0 it does not work in same session.

Score:0

Ubuntu

antonio1

11/2/22, 10:24 PM

I found the solution by using following lines:

prev_user=$(pstree -lu -s $$ |grep --max-count=1 -o '([^)]*)' |head -n 1 | sed 's/[()]//g')
inherit_display=$(xauth -f /home/$prev_user/.Xauthority list|tail -1|cut -d/ -f2|cut -d ' ' -f1)

export DISPLAY="$inherit_display"

prev_user - is getting the previous user (parent user) from which I used su

inherit_display - get exactly the value of DISPLAY for parent user

finally I export the value to my new DISPLAY for root.

works like a sharm.

0 + 0

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EN: How to get variable environment from parent user?

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