Isn't there a text editor somewhere in the XFCE menus? Why not launch that one and then check via ps -efH what programs are running? One of those has got to be the text-editor program?
- start the text editor via its icon in the menus
- open a terminal
- type ps -efH into the terminal
- then check end of the list ... the last program that got executed and is still running should have the highest PID (= process ID) and should thus be on the very end of that list ... the name you see on the right column is the name of the binary.
- close the program
- check again with ps -efH ... the program should have disappeared from the list
- type the name of that binary into the terminal .... if the name was right you should now get a new text editor session.
Voila ... so instead of "sudo gedit ... " you can use that one ( ... sudo whatever-name-ps-will-spit-out ... )