+4  A: 

Because man runs groff itself internally - it's not expecting you to have done it already. Just copy your source.txt straight into /usr/local/man/man1/prog.1, and it should work fine.

Matthew Slattery  2010-08-27 00:22:52
Further, to test with the `man` command, run `man -l prog.1` (or `source.txt` if you prefer that name).
Lars Wirzenius  2010-08-27 00:37:32

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