There's a GUI in Windows to edit the path variable. I was wondering if there's something equivalent in Ubuntu to do the same.
So a text editor is the most logical thing to use. Like
My advice: get used to command line editing for things like this and similar things. It will one day help you fix your problems when not being able to login or Unity crashing just after login.
There is more likely to be a reason for it being done this way. Linux has many more ways of doing things then either of us will ever use but that does not mean someone else does not need them.
For Latex I would suggest adding it to
After adding it in and saving you can check with
if it is set correctly (and this will be permament).