I'd like to add a search term argument to notmuch dump (see
id:"87wrcijn1w.fsf@zancas.localnet" and followup for context). The
"notmuch" way would be to have

    notmuch dump <search-term>

do the right thing, and that is easy enough _except_ that 

   notmuch dump foo

writes the output to file foo.

I see several options.

1) just delete the output file option from notmuch-dump, and use shell
   redirection. So far I don't see a non-contrived example when writing
   an output file directly is useful, but maybe that is just a failure
   of imagination.

2) delete the output file option and a global "--write" option that 
   calls freopen(... stdout). As a bonus(?) this would work for any 
   notmuch command.

3) leave the output option alone and implement a --query=foo option for 
   notmuch dump. This would be the most backward compatible of course,
   but also confusing for users.

Thoughts?

d