Isn't that actually ed/sed syntax?

What is the world coming to when a correction has to get 3 levels deep before it's actually correct on HN?

(And you have less points than either of the ones above you? Seriously?)

Indeed, quick memory recall failure on my part. It's ed syntax which bled into everything else via POSIX basic. However, given the limited number of symbols present, identification can be considered ambiguous :).