I am wondering how to start libreoffice in tty8 from tty1.
I tried
startx -- :1
But then how do I lauch libreoffice?
Using the above command is it possible to chose tty9-12?
Yes.Go to tty1 (Ctrl+Alt+F1), login with your username and passwort, type startx
and you will be transferred in tty8. If you dont have/see unity launcher in tty8, launch Terminal using Ctrl+Alt+T and in Terminal type libreoffice
and that's it - you have Libreoffice in tty8.
If I understand you correctly, you want to start a X application from a tty to be launched in a already running X server (tty7).
You can achieve that setting using DISPLAY
:
$ DISPLAY=:0 libreoffice # just for the current command
$ # or to all the following commands.
$ export DISPLAY=:0
$ libreoffice