OpenEuphoria

Ubuntu sees "ed" as the "GNU Ed" and not the "Euphoria ed." But eui ed.ex does not help either--this only works from the directory where ed.ex is located--and not from a randomly opened terminal.

euphoria/bin doesn't have to be first on your PATH, but if it isn't you'll have to rename the "ed" shell script in euphoria/bin, and perhaps a few others.