This program is actually a stripped-down version of gpg which is
only able to check signatures. It is somewhat smaller than the fully-blown
gpg and uses a different (and simpler) way to check that
the public keys used to make the signature are valid. There are
no configuration files and only a few options are implemented.
gpgv assumes that all keys in the keyring are trustworthy.
By default it uses a keyring named `trustedkeys.gpg' which is
assumed to be in the home directory as defined by GnuPG or set by an
option or an environment variable. An option may be used to specify
another keyring or even multiple keyrings.
The program returns 0 if everything is fine, 1 if at least
one signature was bad, and other error codes for fatal errors.
gpgv recognizes these options:
Gives more information during processing. If used
twice, the input data is listed in detail.
Try to be as quiet as possible.
Add file to the list of keyrings.
If file begins with a tilde and a slash, these
are replaced by the HOME directory. If the filename
does not contain a slash, it is assumed to be in the
home-directory ("~/.gnupg" if --homedir is not used).
Write special status strings to the file descriptor n. See the
file DETAILS in the documentation for a listing of them.
Write log output to file descriptor n and not to stderr.
GnuPG normally checks that the timestamps associated with keys and
signatures have plausible values. However, sometimes a signature seems to
be older than the key due to clock problems. This option turns these
checks into warnings.
Set the name of the home directory to dir. If this option is not
used, the home directory defaults to `~/.gnupg'. It is only
recognized when given on the command line. It also overrides any home
directory stated through the environment variable `GNUPGHOME' or
(on W32 systems) by means of the Registry entry
gpgv sigfile [datafile]
Verify the signature of the file. The second form is used for detached
signatures, where sigfile is the detached signature (either
ASCII-armored or binary) and datafile contains the signed data;
if datafile is "-" the signed data is expected on
stdin; if datafile is not given the name of the file
holding the signed data is constructed by cutting off the extension
(".asc", ".sig" or ".sign") from sigfile.