There's some digging here: http://unix.stackexchange.com/questions/147143/when-and-how-was-the-double-dash-introduced-as-an-end-of-options-delimiter http://unix

There's some digging here: http://unix.stackexchange.com/questions/147143/when-and-how-was-the-double-dash-introduced-as-an-end-of-options-delimiter http://unix.stackexchange.com/questions/147143/when-and-how-... Looks like the convention was introduced as part of getopt in AT&T Unix System III (1980), though initially only in a handful of places. Then POSIX adopted it as standard for all utilities sometime later.