On Friday, April 21, 2017, Ron Natalie <ron@ronnatalie.com> wrote:
Shebang is very old.   Earliest uses are around 1862 according to the OED.    It's listed as American Slang of obscure origin.

Most of us are probably familiar with the word, but it is more interesting when and why it was first used in the context of '#!'.  It seems Dennis did not use that term in the beginning.

--Andy