Clem Cole:
Clearly from the time, ditroff did not yet exist. The more I think about
it, Brian K actually might know some of the story.
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I'm quite sure Brian Kernighan knows the full story of the origins
of typesetter-independent troff (as it was originally called, in
CSTR 97, published in 1981; the binary was just /usr/bin/troff).
The reason I'm so sure of that is that it was Brian who rewrote
troff to bring it into the modern era and to make it supportable.
He's also the author of the CSTR.
Norman Wilson
Toronto ON