previously we deleted the subcommand name from argv before passing to
the subcommand. In this version, the deletion is done in the actual
subcommands. Although this causes some duplication of code, it allows
us to be more flexible about how we parse command line arguments in
the subcommand, including possibly using off-the-shelf routines like
getopt_long that expect the name of the command in argv[0].
From both the implementation and from the documentation. This is
handled generically in the library for all search-based commands,
so count doesn't need special treatment.
If no parameters are given to notmuch-count, or just '' or '*' are
given, return the total number of messages in the database.
update notmuch count help
Getting the count of matching threads or messages is a fairly
expensive operation. Xapian provides a very efficient mechanism that
returns an approximate value, so use that for this new command.
This returns the number of matching messages, not threads, as that is
cheap to compute.
Signed-off-by: Keith Packard <keithp@keithp.com>