bypassing the unison GUI

I use unison on a number of machines, all running ubuntu 20.04. For some baffling reason, one morning two of these machines starting opening a GUI whenever I did a file transfer. The other machine only generates text. The default.prf files on all machines are identical so that's not the source of the difference. I'd like to disable the GUI on the two machines that are running it. Couldn't find anything in the manual about how to do this. Could somebody advise please?

Thanks very much for any advise.

Solution 1:

There is unison with text UI and unison-gtk with a GUI. It seems your system has started to default to the GUI version.

Please check the chain of links until you reach the executable file(s) and let us hope there is still a text UI version in 20.04 (It is in 18.04 which I'm running: /usr/bin/unison-2.48.4 and /usr/bin/unison-2.48.4-gtk)