As another comment noted, Perforce used this syntax too - Which is probably where Blaze got it from. I can't speak to earlier examples, but it's "obvious" enoug

As another comment noted, Perforce used this syntax too - Which is probably where Blaze got it from. I can't speak to earlier examples, but it's "obvious" enough that I would not be surprised if someone found one. I often think that a substantial portion of my job is software archaeology...