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Regex `/pattern/g` and ed `:g/pattern/`: which came first, and why `g`?

The g option (/pattern/g) for many tools that use regex-style pattern matching and the :g command in ed/ex/vi/vim have pretty similar usage and meaning: match the given regex "globally", i.e., don't stop after the first match.

I have a two-fold question about this:

  • Which came first, the g: command or the //g option, and in which tool? It looks like most tools (such as sed) that use the g option in their pattern-matching are really just directly or indirectly emulating ed. For instance, in the post-Perl age, most tools that use regex allow the g option because Perl does, and Perl, it would appear, does it because ed -> sed -> Perl. So I wouldn't be surprised if the answer is "they were introduced simultaneously in the original ed tool, and have no historical precedent beyond that."
  • Why is this called the global option (or command)? There's really nothing "global" about it; the :g command takes a range of lines just like any other ed command, and the /g option doesn't extend the range of the search in any way (it just allows multiple hits). I suppose I can't think of a better name, but the chosen one just seems odd to me, so I'm wondering if there's some reason for it I'm not seeing.

P.S.: I've tagged this question with "regular-expressions" even though it's not exactly about regular expressions, since it does have a little bit to do with the historical basis for a particular usage of regex in various tools.