I work mostly from the command line, but sometimes I need to open an external GUI program to do something visual.
Since I don't often use those programs, I may forget what I installed to open a particular file.
The command `xdg-open` from xdg-utils will try to DTRT and invoke the right program for you. You can query and change preferred programs using `xdg-mime`. And this works without a desktop environment (e.g. I use i3wm).
Mike Gerwitz's personal Mastodon instance