GPGVSection: GNU Privacy Guard 2.1 (1)
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NAMEgpgv - Verify OpenPGP signatures
SYNOPSISgpgv [options] signed_files
DESCRIPTIONgpgv is an OpenPGP signature verification tool.
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. That does also mean that it does not check for expired or revoked keys.
By default a keyring named 'trustedkeys.kbx' is used; if that does not exist a keyring named 'trustedkeys.gpg' is used. The default keyring is assumed to be in the home directory of GnuPG, either the default home directory or the one set by an option or an environment variable. The option --keyring may be used to specify a different 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.
OPTIONSgpgv 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.
- --keyring file
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).
- --output file
Write output to file; to write to stdout use -. This
option can be used to get the signed text from a cleartext or binary
signature; it also works for detached signatures, but in that case
this option is in general not useful. Note that an existing file will
- --status-fd n
Write special status strings to the file descriptor n. See the
file DETAILS in the documentation for a listing of them.
- --logger-fd n
Write log output to file descriptor n and not to stderr.
- --log-file file
Same as --logger-fd, except the logger data is written to
file file. Use 'socket://' to log to socket.
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.
- --homedir dir
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 Windows systems) by means of the Registry entry
On Windows systems it is possible to install GnuPG as a portable application. In this case only this command line option is considered, all other ways to set a home directory are ignored.
To install GnuPG as a portable application under Windows, create an empty file named 'gpgconf.ctl' in the same directory as the tool 'gpgconf.exe'. The root of the installation is then that directory; or, if 'gpgconf.exe' has been installed directly below a directory named 'bin', its parent directory. You also need to make sure that the following directories exist and are writable: 'ROOT/home' for the GnuPG home and 'ROOT/var/cache/gnupg' for internal cache files.
- --weak-digest name
Treat the specified digest algorithm as weak. Signatures made over
weak digests algorithms are normally rejected. This option can be
supplied multiple times if multiple algorithms should be considered
weak. MD5 is always considered weak, and does not need to be listed
This option enables a mode in which filenames of the form
'-&n', where n is a non-negative decimal number,
refer to the file descriptor n and not to a file with that name.
- gpgv pgpfile
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.
The default keyring with the allowed keys.
Used to locate the default home directory.
If set directory used instead of "~/.gnupg".
The full documentation for this tool is maintained as a Texinfo manual. If GnuPG and the info program are properly installed at your site, the command
should give you access to the complete manual including a menu structure and an index.
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