When I run
gpg --with-fingerprints --with-colons keyfile.key, I get a machine parsable output on stdout containing the key fingerprint for the key inside the keyfile (which is exactly what I want), plus the following error on stderr:
gpg: WARNING: no command supplied. Trying to guess what you mean ...
So GnuPG is guessing the command correctly, but for my life I can't figure out what command it is guessing. I have tried almost all of the commands listed on the man page. I'm using GnuPG 2.2.
Does anybody know the correct command to read a key file and show information about the key?
Edit: Ideally the mechanism would be able to read the keyfile from stdin, such as
cat keyfile.key | gpg --some-command
I should have mentioned this earlier but so many commands for gpg work with stdin I didn't even consider it a relevant constraint.