gpg-preset-passphrase is invoked this way:
gpg-preset-passphrase [options] [command] keygrip
keygrip is a 40 character string of hexadecimal characters
identifying the key for which the passphrase should be set or cleared.
This keygrip is listed along with the key when running the command:
gpgsm --dump-secret-keys
. One of the following command options
must be given:
--preset
stdin
.
--forget
The following additional options may be used:
-v
--verbose
-P
string--passphrase
stringstdin
, use the supplied
string as passphrase. Note that this makes the passphrase visible
for other users.