Well, people joke about Emacs being an OS. If you take them seriously, I think it&#x27;s an example of an OS where you can run graphical applications but have a standardized way to run text-based commands from any app (using execute-extended-command, bound by default to Meta-x).<p>It&#x27;s not really practical to use Emacs as your only OS right now, but it certainly has many of the applications I need day to day: a text editor (obviously), a web-browser (that can display images, but currently does not run JavaScript), a PDF viewer, email clients, feed readers, command shells, several videogames, etc.