Detached signature as a pass-through filter?

[Michael Young]

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I'd like to use GnuPG to sign an intermediate result, something like:

    command ... | gpg --detach-sign -o signature_file | other_command ...

This specific incantation doesn't work.  Standard output is empty.

Is there any way to convince GnuPG to pass the input through to
standard output?  (And if not, would it be reasonable to add a
switch to do this?)

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