I have been through this a million times, but I never seem to remember, and have a hard time finding the answer online or in my archives.
On a Linux system, how should I set org-file-apps to allow org to open odt files in libreoffice, html files in Firefox, and pdf files in evince (especially in export-and-open commands)?
I have tried a couple of htings; this is what C-h v org-file-apps currently says:
Its value is ((remote . emacs) (system . mailcap) (t . mailcap))
Original value was
((auto-mode . emacs)
("\\.mm\\'" . default)
("\\.x?html?\\'" . default)
("\\.pdf\\'" . default))