neulab/tldr huggingface dataset:
--hidden-recipient name -R     Encrypt for user ID name, but hide the key ID of this user's key. This option helps to hide the receiver of the message and is a limited countermeasure against traffic analysis. If this option or --recipient is not specified, GnuPG asks for the user ID unless --default-recipient is given.
--recipient-file file -f     This option is similar to --recipient except that it encrypts to a key stored in the given file.  file must be the name of a file containing exactly one key.  gpg assumes that the key in this file is fully valid.
--hidden-recipient-file file -F     This option is similar to --hidden-recipient except that it encrypts to a key stored in the given file.  file must be the name of a file containing exactly one key.  gpg assumes that the key in this file is fully valid.
--encrypt-to name Same as --recipient but this one is intended for use in the options file and may be used with your own user-id as an "encrypt- to-self". These keys are only used when there are other recipients given either by use of --recipient or by the asked user id.  No trust checking is performed for these user ids and even disabled keys can be used.
--hidden-encrypt-to name Same as --hidden-recipient but this one is intended for use in the options file and may be used with your own user-id as a hidden "encrypt-to-self". These keys are only used when there are other recipients given either by use of --recipient or by the asked user id.  No trust checking is performed for these user ids and even disabled keys can be used.
--no-encrypt-to Disable the use of all --encrypt-to and --hidden-encrypt-to keys.
--group {name=value} Sets up a named group, which is similar to aliases in email programs.  Any time the group name is a recipient (-r or --recipient), it will be expanded to the values specified. Multiple groups with the same name are automatically merged into a single group.
The values are key IDs or fingerprints, but any key description is accepted. Note that a value with spaces in it will be treated as two different values. Note also there is only one level of expansion --- you cannot make an group that points to another group. When used from the command line, it may be necessary to quote the argument to this option to prevent the shell from treating it as multiple arguments.
--ungroup name Remove a given entry from the --group list.
--no-groups Remove all entries from the --group list.
--local-user name -u     Use name as the key to sign with. Note that this option overrides --default-key.
--sender mbox This option has two purposes.  mbox must either be a complete user id with a proper mail address or just a mail address.  When creating a signature this option tells gpg the user id of a key used to make a signature if the key was not directly specified by a user id.  When verifying a signature the mbox is used to restrict the information printed by the TOFU code to matching user ids.
--try-secret-key name For hidden recipients GPG needs to know the keys to use for trial decryption.  The key set with --default-key is always tried first, but this is often not sufficient.  This option allows setting more keys to be used for trial decryption.  Although any valid user-id specification may be used for name it makes sense to use at least the long keyid to avoid ambiguities.  Note that gpg-agent might pop up a pinentry for a lot keys to do the trial decryption.  If you want to stop all further trial decryption you may use close- window button instead of the cancel button.
--try-all-secrets Don't look at the key ID as stored in the message but try all secret keys in turn to find the right decryption key. This option forces the behaviour as used by anonymous recipients (created by using --throw-keyids or --hidden-recipient) and might come handy in case where an encrypted message contains a bogus key ID.
--skip-hidden-recipients --no-skip-hidden-recipients During decryption skip all anonymous recipients.  This option helps in the case that people use the hidden recipients feature to hide their own encrypt-to key from others.  If one has many secret keys this may lead to a major annoyance because all keys are tried in turn to decrypt something which was not really intended for it. The drawback of this option is that it is currently not possible to decrypt a message which includes real anonymous recipients.
--armor -a     Create ASCII armored output.  The default is to create the binary OpenPGP format.
--no-armor Assume the input data is not in ASCII armored format.
--output file -o file Write output to file.  To write to stdout use - as the filename.
--max-output n This option sets a limit on the number of bytes that will be generated when processing a file. Since OpenPGP supports various levels of compression, it is possible that the plaintext of a given message may be significantly larger than the original OpenPGP message. While GnuPG works properly with such messages, there is often a desire to set a maximum file size that will be generated before processing is forced to stop by the OS limits. Defaults to 0, which means "no limit".
--input-size-hint n This option can be used to tell GPG the size of the input data in bytes.  n must be a positive base-10 number.  This option is only useful if the input is not taken from a file.  GPG may use this hint to optimize its buffer allocation strategy.  It is also used by the --status-fd line ``PROGRESS'' to provide a value for ``total'' if that is not available by other means.
--key-origin string[,url] gpg can track the origin of a key. Certain origins are implicitly known (e.g. keyserver, web key directory) and set.  For a standard import the origin of the keys imported can be set with this option.  To list the possible values use "help" for string.  Some origins can store an optional url argument.  That URL can appended to string after a comma.
--import-options parameters This is a space or comma delimited string that gives options for importing keys. Options can be prepended with a `no-' to give the opposite meaning. The options are:
import-local-sigs Allow importing key signatures marked as "local". This is not generally useful unless a shared keyring scheme is being used.  Defaults to no.
keep-ownertrust Normally possible still existing ownertrust values of a key are cleared if a key is imported.  This is in general desirable so that a formerly deleted key does not automatically gain an ownertrust values merely due to import.  On the other hand it is sometimes necessary to re- import a trusted set of keys again but keeping already assigned ownertrust values.  This can be achieved by using this option.
repair-pks-subkey-bug During import, attempt to repair the damage caused by the PKS keyserver bug (pre version 0.9.6) that mangles keys with multiple subkeys. Note that this cannot completely repair the damaged key as some crucial data is removed by the keyserver, but it does at least give you back one subkey. Defaults to no for regular --import and to yes for keyserver --receive-keys.
import-show show-only Show a listing of the key as imported right before it is stored.  This can be combined with the option --dry-run to only look at keys; the option show-only is a shortcut for this combination.  The command --show-keys is another shortcut for this.  Note that suffixes like '#' for "sec" and "sbb" lines may or may not be printed.
import-export Run the entire import code but instead of storing the key to the local keyring write it to the output.  The export options export-pka and export-dane affect the output.  This option can be used to remove all invalid parts from a key without the need to store it.
merge-only During import, allow key updates to existing keys, but do not allow any new keys to be imported. Defaults to no.
import-clean After import, compact (remove all signatures except the self-signature) any user IDs from the new key that are not usable.  Then, remove any signatures from the new key that are not usable.  This includes signatures that were issued by keys that are not present on the keyring. This option is the same as running the --edit-key command "clean" after import. Defaults to no.
self-sigs-only Accept only self-signatures while importing a key.  All other key signatures are skipped at an early import stage. This option can be used with keyserver-options to mitigate attempts to flood a key with bogus signatures from a keyserver.  The drawback is that all other valid key signatures, as required by the Web of Trust are also not imported.  Note that when using this option along with import-clean it suppresses the final clean step after merging the imported key into the existing key.
repair-keys After import, fix various problems with the keys.  For example, this reorders signatures, and strips duplicate signatures.  Defaults to yes.
import-minimal Import the smallest key possible. This removes all signatures except the most recent self-signature on each user ID. This option is the same as running the --edit-key command "minimize" after import.  Defaults to no.
restore import-restore Import in key restore mode.  This imports all data which is usually skipped during import; including all GnuPG specific data.  All other contradicting options are overridden.
--import-filter {name=expr} --export-filter {name=expr} These options define an import/export filter which are applied to the imported/exported keyblock right before it will be stored/written.  name defines the type of filter to use, expr the expression to evaluate.  The option can be used several times which then appends more expression to the same name.
The available filter types are:
keep-uid This filter will keep a user id packet and its dependent packets in the keyblock if the expression evaluates to true.
drop-subkey This filter drops the selected subkeys.  Currently only implemented for --export-filter.
drop-sig This filter drops the selected key signatures on user ids. Self-signatures are not considered.  Currently only implemented for --import-filter.
For the syntax of the expression see the chapter "FILTER EXPRESSIONS". The property names for the expressions depend on the actual filter type and are indicated in the following table.
The available properties are:
uid    A string with the user id.  (keep-uid)
mbox   The addr-spec part of a user id with mailbox or the empty string.  (keep-uid)
key_algo A number with the public key algorithm of a key or subkey packet.  (drop-subkey)
key_created key_created_d The first is the timestamp a public key or subkey packet was created.  The second is the same but given as an ISO string, e.g. "2016-08-17". (drop-subkey)
fpr    The hexified fingerprint of the current subkey or primary key.  (drop-subkey)
primary Boolean indicating whether the user id is the primary one. (keep-uid)
expired Boolean indicating whether a user id (keep-uid), a key (drop-subkey), or a signature (drop-sig) expired.
revoked Boolean indicating whether a user id (keep-uid) or a key (drop-subkey) has been revoked.
disabled Boolean indicating whether a primary key is disabled. (not used)
secret Boolean indicating whether a key or subkey is a secret one. (drop-subkey)
usage  A string indicating the usage flags for the subkey, from the sequence ``ecsa?''.  For example, a subkey capable of just signing and authentication would be an exact match for ``sa''. (drop-subkey)
sig_created sig_created_d The first is the timestamp a signature packet was created. The second is the same but given as an ISO date string, e.g. "2016-08-17". (drop-sig)
sig_algo A number with the public key algorithm of a signature packet. (drop-sig)
sig_digest_algo A number with the digest algorithm of a signature packet. (drop-sig)
--export-options parameters This is a space or comma delimited string that gives options for exporting keys.  Options can be prepended with a `no-' to give the opposite meaning.  The options are:
export-local-sigs Allow exporting key signatures marked as "local". This is not generally useful unless a shared keyring scheme is being used.  Defaults to no.
export-attributes Include attribute user IDs (photo IDs) while exporting. Not including attribute user IDs is useful to export keys that are going to be used by an OpenPGP program that does not accept attribute user IDs.  Defaults to yes.
export-sensitive-revkeys Include designated revoker information that was marked as "sensitive". Defaults to no.
backup export-backup Export for use as a backup.  The exported data includes all data which is needed to restore the key or keys later with GnuPG.  The format is basically the OpenPGP format but enhanced with GnuPG specific data.  All other contradicting options are overridden.
export-clean Compact (remove all signatures from) user IDs on the key being exported if the user IDs are not usable. Also, do not export any signatures that are not usable. This includes signatures that were issued by keys that are not present on the keyring. This option is the same as running the --edit- key command "clean" before export except that the local copy of the key is not modified. Defaults to no.
export-minimal Export the smallest key possible. This removes all signatures except the most recent self-signature on each user ID. This option is the same as running the --edit-key command "minimize" before export except that the local copy of the key is not modified. Defaults to no.
export-pka Instead of outputting the key material output PKA records suitable to put into DNS zone files.  An ORIGIN line is printed before each record to allow diverting the records to the corresponding zone file.
export-dane Instead of outputting the key material output OpenPGP DANE records suitable to put into DNS zone files.  An ORIGIN line is printed before each record to allow diverting the records to the corresponding zone file.
--with-colons Print key listings delimited by colons. Note that the output will be encoded in UTF-8 regardless of any --display-charset setting. This format is useful when GnuPG is called from scripts and other programs as it is easily machine parsed. The details of this format are documented in the file ‘doc/DETAILS’, which is included in the GnuPG source distribution.
--fixed-list-mode Do not merge primary user ID and primary key in --with-colon listing mode and print all timestamps as seconds since 1970-01-01. Since GnuPG 2.0.10, this mode is always used and thus this option is obsolete; it does not harm to use it though.
--legacy-list-mode Revert to the pre-2.1 public key list mode.  This only affects the human readable output and not the machine interface (i.e. --with- colons).  Note that the legacy format does not convey suitable information for elliptic curves.
--with-fingerprint Same as the command --fingerprint but changes only the format of the output and may be used together with another command.
--with-subkey-fingerprint If a fingerprint is printed for the primary key, this option forces printing of the fingerprint for all subkeys.  This could also be achieved by using the --with-fingerprint twice but by using this option along with keyid-format "none" a compact fingerprint is printed.
--with-icao-spelling Print the ICAO spelling of the fingerprint in addition to the hex digits.
--with-keygrip Include the keygrip in the key listings.  In --with-colons mode this is implicitly enable for secret keys.
--with-key-origin Include the locally held information on the origin and last update of a key in a key listing.  In --with-colons mode this is always printed.  This data is currently experimental and shall not be considered part of the stable API.
--with-wkd-hash Print a Web Key Directory identifier along with each user ID in key listings.  This is an experimental feature and semantics may change.
--with-secret Include info about the presence of a secret key in public key listings done with --with-colons.
OpenPGP protocol specific options
-t, --textmode --no-textmode Treat input files as text and store them in the OpenPGP canonical text form with standard "CRLF" line endings. This also sets the necessary flags to inform the recipient that the encrypted or signed data is text and may need its line endings converted back to whatever the local system uses. This option is useful when communicating between two platforms that have different line ending conventions (UNIX-like to Mac, Mac to Windows, etc). --no- textmode disables this option, and is the default.
--force-v3-sigs --no-force-v3-sigs
--force-v4-certs --no-force-v4-certs These options are obsolete and have no effect since GnuPG 2.1.
--force-mdc --disable-mdc These options are obsolete and have no effect since GnuPG 2.2.8. The MDC is always used.  But note: If the creation of a legacy non-MDC message is exceptionally required, the option --rfc2440 allows for this.
--disable-signer-uid By default the user ID of the signing key is embedded in the data signature.  As of now this is only done if the signing key has been specified with local-user using a mail address, or with sender.  This information can be helpful for verifier to locate the key; see option --auto-key-retrieve.
--include-key-block This option is used to embed the actual signing key into a data signature.  The embedded key is stripped down to a single user id and includes only the signing subkey used to create the signature as well as as valid encryption subkeys.  All other info is removed from the key to keep it and thus the signature small.  This option is the OpenPGP counterpart to the gpgsm option --include-certs.
--personal-cipher-preferences string Set the list of personal cipher preferences to string.  Use gpg --version to get a list of available algorithms, and use none to set no preference at all.  This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients.  The most highly ranked cipher in this list is also used for the --symmetric encryption command.
--personal-digest-preferences string Set the list of personal digest preferences to string.  Use gpg --version to get a list of available algorithms, and use none to set no preference at all.  This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients.  The most highly ranked digest algorithm in this list is also used when signing without encryption (e.g. --clear-sign or --sign).
--personal-compress-preferences string Set the list of personal compression preferences to string.  Use gpg --version to get a list of available algorithms, and use none to set no preference at all.  This allows the user to safely override the algorithm chosen by the recipient key preferences, as GPG will only select an algorithm that is usable by all recipients.  The most highly ranked compression algorithm in this list is also used when there are no recipient keys to consider (e.g. --symmetric).
--s2k-cipher-algo name Use name as the cipher algorithm for symmetric encryption with a passphrase if --personal-cipher-preferences and --cipher-algo are not given.  The default is AES-128.
--s2k-digest-algo name Use name as the digest algorithm used to mangle the passphrases for symmetric encryption.  The default is SHA-1.
--s2k-mode n Selects how passphrases for symmetric encryption are mangled. If n is 0 a plain passphrase (which is in general not recommended) will be used, a 1 adds a salt (which should not be used) to the passphrase and a 3 (the default) iterates the whole process a number of times (see --s2k-count).
--s2k-count n Specify how many times the passphrases mangling for symmetric encryption is repeated.  This value may range between 1024 and 65011712 inclusive.  The default is inquired from gpg-agent.  Note that not all values in the 1024-65011712 range are legal and if an illegal value is selected, GnuPG will round up to the nearest legal value.  This option is only meaningful if --s2k-mode is set to the default of 3.
Compliance options
These options control what GnuPG is compliant to. Only one of these options may be active at a time. Note that the default setting of this is nearly always the correct one. See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS section below before using one of these options.
--gnupg Use standard GnuPG behavior. This is essentially OpenPGP behavior (see --openpgp), but with some additional workarounds for common compatibility problems in different versions of PGP. This is the default option, so it is not generally needed, but it may be useful to override a different compliance option in the gpg.conf file.
--openpgp Reset all packet, cipher and digest options to strict OpenPGP behavior. Use this option to reset all previous options like --s2k-*, --cipher-algo, --digest-algo and --compress-algo to OpenPGP compliant values. All PGP workarounds are disabled.
--rfc4880 Reset all packet, cipher and digest options to strict RFC-4880 behavior. Note that this is currently the same thing as --openpgp.
--rfc4880bis Enable experimental features from proposed updates to RFC-4880. This option can be used in addition to the other compliance options.  Warning: The behavior may change with any GnuPG release and created keys or data may not be usable with future GnuPG versions.
--rfc2440 Reset all packet, cipher and digest options to strict RFC-2440 behavior.  Note that by using this option encryption packets are created in a legacy mode without MDC protection.  This is dangerous and should thus only be used for experiments.  See also option --ignore-mdc-error.
--pgp6 Set up all options to be as PGP 6 compliant as possible. This restricts you to the ciphers IDEA (if the IDEA plugin is installed), 3DES, and CAST5, the hashes MD5, SHA1 and RIPEMD160, and the compression algorithms none and ZIP. This also disables --throw-keyids, and making signatures with signing subkeys as PGP 6 does not understand signatures made by signing subkeys.
This option implies --escape-from-lines.
--pgp7 Set up all options to be as PGP 7 compliant as possible. This is identical to --pgp6 except that MDCs are not disabled, and the list of allowable ciphers is expanded to add AES128, AES192, AES256, and TWOFISH.
--pgp8 Set up all options to be as PGP 8 compliant as possible. PGP 8 is a lot closer to the OpenPGP standard than previous versions of PGP, so all this does is disable --throw-keyids and set --escape- from-lines.  All algorithms are allowed except for the SHA224, SHA384, and SHA512 digests.
--compliance string This option can be used instead of one of the options above. Valid values for string are the above option names (without the double dash) and possibly others as shown when using "help" for value.
Doing things one usually doesn't want to do
-n --dry-run Don't make any changes (this is not completely implemented).
--list-only Changes the behaviour of some commands. This is like --dry-run but different in some cases. The semantic of this option may be extended in the future. Currently it only skips the actual decryption pass and therefore enables a fast listing of the encryption keys.
-i --interactive Prompt before overwriting any files.
--debug-level level Select the debug level for investigating problems. level may be a numeric value or by a keyword:
none   No debugging at all.  A value of less than 1 may be used instead of the keyword.
basic  Some basic debug messages.  A value between 1 and 2 may be used instead of the keyword.
advanced More verbose debug messages.  A value between 3 and 5 may be used instead of the keyword.
expert Even more detailed messages.  A value between 6 and 8 may be used instead of the keyword.
guru   All of the debug messages you can get. A value greater than 8 may be used instead of the keyword.  The creation of hash tracing files is only enabled if the keyword is used.
How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging.
--debug flags Set debugging flags. All flags are or-ed and flags may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used.
--debug-all Set all useful debugging flags.
--debug-iolbf Set stdout into line buffered mode.  This option is only honored when given on the command line.
--faked-system-time epoch This option is only useful for testing; it sets the system time back or forth to epoch which is the number of seconds elapsed since the year 1970.  Alternatively epoch may be given as a full ISO time string (e.g. "20070924T154812").
If you suffix epoch with an exclamation mark (!), the system time will appear to be frozen at the specified time.
--enable-progress-filter Enable certain PROGRESS status outputs. This option allows frontends to display a progress indicator while gpg is processing larger files.  There is a slight performance overhead using it.
--status-fd n Write special status strings to the file descriptor n.  See the file DETAILS in the documentation for a listing of them.
--status-file file Same as --status-fd, except the status data is written to file file.
--logger-fd n Write log output to file descriptor n and not to STDERR.
--log-file file --logger-file file Same as --logger-fd, except the logger data is written to file file.  Use ‘socket://’ to log to a socket.  Note that in this version of gpg the option has only an effect if --batch is also used.
--attribute-fd n Write attribute subpackets to the file descriptor n. This is most useful for use with --status-fd, since the status messages are needed to separate out the various subpackets from the stream delivered to the file descriptor.
--attribute-file file Same as --attribute-fd, except the attribute data is written to file file.
--comment string --no-comments Use string as a comment string in cleartext signatures and ASCII armored messages or keys (see --armor). The default behavior is not to use a comment string. --comment may be repeated multiple times to get multiple comment strings. --no-comments removes all comments.  It is a good idea to keep the length of a single comment below 60 characters to avoid problems with mail programs wrapping such lines.  Note that comment lines, like all other header lines, are not protected by the signature.
--emit-version --no-emit-version Force inclusion of the version string in ASCII armored output.  If given once only the name of the program and the major number is emitted, given twice the minor is also emitted, given thrice the micro is added, and given four times an operating system identification is also emitted.  --no-emit-version (default) disables the version line.
--sig-notation {name=value} --cert-notation {name=value} -N, --set-notation {name=value} Put the name value pair into the signature as notation data.  name must consist only of printable characters or spaces, and must contain a '@' character in the form keyname@domain.example.com (substituting the appropriate keyname and domain name, of course). This is to help prevent pollution of the IETF reserved notation namespace. The --expert flag overrides the '@' check. value may be any printable string; it will be encoded in UTF-8, so you should check that your --display-charset is set correctly. If you prefix name with an exclamation mark (!), the notation data will be flagged as critical (rfc4880:5.2.3.16). --sig-notation sets a notation for data signatures. --cert-notation sets a notation for key signatures (certifications). --set-notation sets both.
There are special codes that may be used in notation names. "%k" will be expanded into the key ID of the key being signed, "%K" into the long key ID of the key being signed, "%f" into the fingerprint of the key being signed, "%s" into the key ID of the key making the signature, "%S" into the long key ID of the key making the signature, "%g" into the fingerprint of the key making the signature (which might be a subkey), "%p" into the fingerprint of the primary key of the key making the signature, "%c" into the signature count from the OpenPGP smartcard, and "%%" results in a single "%". %k, %K, and %f are only meaningful when making a key signature (certification), and %c is only meaningful when using the OpenPGP smartcard.
--known-notation name Adds name to a list of known critical signature notations.  The effect of this is that gpg will not mark a signature with a critical signature notation of that name as bad.  Note that gpg already knows by default about a few critical signatures notation names.
--sig-policy-url string --cert-policy-url string --set-policy-url string Use string as a Policy URL for signatures (rfc4880:5.2.3.20).  If you prefix it with an exclamation mark (!), the policy URL packet will be flagged as critical. --sig-policy-url sets a policy url for data signatures. --cert-policy-url sets a policy url for key signatures (certifications). --set-policy-url sets both.
The same %-expandos used for notation data are available here as well.
--sig-keyserver-url string Use string as a preferred keyserver URL for data signatures. If you prefix it with an exclamation mark (!), the keyserver URL packet will be flagged as critical.
--set-filename string Use string as the filename which is stored inside messages.  This overrides the default, which is to use the actual filename of the file being encrypted.  Using the empty string for string effectively removes the filename from the output.
--for-your-eyes-only --no-for-your-eyes-only Set the `for your eyes only' flag in the message. This causes GnuPG to refuse to save the file unless the --output option is given, and PGP to use a "secure viewer" with a claimed Tempest- resistant font to display the message. This option overrides --set-filename.  --no-for-your-eyes-only disables this option.
--use-embedded-filename --no-use-embedded-filename Try to create a file with a name as embedded in the data. This can be a dangerous option as it enables overwriting files.  Defaults to no.  Note that the option --output overrides this option.
--cipher-algo name Use name as cipher algorithm. Running the program with the command --version yields a list of supported algorithms. If this is not used the cipher algorithm is selected from the preferences stored with the key. In general, you do not want to use this option as it allows you to violate the OpenPGP standard.  --personal-cipher- preferences is the safe way to accomplish the same thing.
--digest-algo name Use name as the message digest algorithm. Running the program with the command --version yields a list of supported algorithms. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. --personal-digest-preferences is the safe way to accomplish the same thing.
--compress-algo name Use compression algorithm name. "zlib" is RFC-1950 ZLIB compression. "zip" is RFC-1951 ZIP compression which is used by PGP.  "bzip2" is a more modern compression scheme that can compress some things better than zip or zlib, but at the cost of more memory used during compression and decompression. "uncompressed" or "none" disables compression. If this option is not used, the default behavior is to examine the recipient key preferences to see which algorithms the recipient supports. If all else fails, ZIP is used for maximum compatibility.
ZLIB may give better compression results than ZIP, as the compression window size is not limited to 8k. BZIP2 may give even better compression results than that, but will use a significantly larger amount of memory while compressing and decompressing. This may be significant in low memory situations. Note, however, that PGP (all versions) only supports ZIP compression. Using any algorithm other than ZIP or "none" will make the message unreadable with PGP. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. --personal-compress-preferences is the safe way to accomplish the same thing.
--cert-digest-algo name Use name as the message digest algorithm used when signing a key. Running the program with the command --version yields a list of supported algorithms. Be aware that if you choose an algorithm that GnuPG supports but other OpenPGP implementations do not, then some users will not be able to use the key signatures you make, or quite possibly your entire key.
--disable-cipher-algo name Never allow the use of name as cipher algorithm.  The given name will not be checked so that a later loaded algorithm will still get disabled.
--disable-pubkey-algo name Never allow the use of name as public key algorithm.  The given name will not be checked so that a later loaded algorithm will still get disabled.
--throw-keyids --no-throw-keyids Do not put the recipient key IDs into encrypted messages. This helps to hide the receivers of the message and is a limited countermeasure against traffic analysis. ([Using a little social engineering anyone who is able to decrypt the message can check whether one of the other recipients is the one he suspects.])  On the receiving side, it may slow down the decryption process because all available secret keys must be tried.  --no-throw- keyids disables this option. This option is essentially the same as using --hidden-recipient for all recipients.
--not-dash-escaped This option changes the behavior of cleartext signatures so that they can be used for patch files. You should not send such an armored file via email because all spaces and line endings are hashed too. You can not use this option for data which has 5 dashes at the beginning of a line, patch files don't have this. A special armor header line tells GnuPG about this cleartext signature option.
--escape-from-lines --no-escape-from-lines Because some mailers change lines starting with "From " to ">From " it is good to handle such lines in a special way when creating cleartext signatures to prevent the mail system from breaking the signature. Note that all other PGP versions do it this way too. Enabled by default. --no-escape-from-lines disables this option.
--passphrase-repeat n Specify how many times gpg will request a new passphrase be repeated.  This is useful for helping memorize a passphrase. Defaults to 1 repetition; can be set to 0 to disable any passphrase repetition.  Note that a n greater than 1 will pop up the pinentry window n+1 times even if a modern pinentry with two entry fields is used.
--passphrase-fd n Read the passphrase from file descriptor n. Only the first line will be read from file descriptor n. If you use 0 for n, the passphrase will be read from STDIN. This can only be used if only one passphrase is supplied.
Note that since Version 2.0 this passphrase is only used if the option --batch has also been given. Since Version 2.1 the --pinentry-mode also needs to be set to loopback.
--passphrase-file file Read the passphrase from file file. Only the first line will be read from file file. This can only be used if only one passphrase is supplied. Obviously, a passphrase stored in a file is of questionable security if other users can read this file. Don't use this option if you can avoid it.
--passphrase string Use string as the passphrase. This can only be used if only one passphrase is supplied. Obviously, this is of very questionable security on a multi-user system. Don't use this option if you can avoid it.
--pinentry-mode mode Set the pinentry mode to mode.  Allowed values for mode are:
default Use the default of the agent, which is ask.
ask    Force the use of the Pinentry.
cancel Emulate use of Pinentry's cancel button.
error  Return a Pinentry error (``No Pinentry'').
loopback Redirect Pinentry queries to the caller.  Note that in contrast to Pinentry the user is not prompted again if he enters a bad password.
--no-symkey-cache Disable the passphrase cache used for symmetrical en- and decryption.  This cache is based on the message specific salt value (cf. --s2k-mode).
--request-origin origin Tell gpg to assume that the operation ultimately originated at origin.  Depending on the origin certain restrictions are applied and the Pinentry may include an extra note on the origin. Supported values for origin are: local which is the default, remote to indicate a remote origin or browser for an operation requested by a web browser.
--command-fd n This is a replacement for the deprecated shared-memory IPC mode. If this option is enabled, user input on questions is not expected from the TTY but from the given file descriptor. It should be used together with --status-fd. See the file doc/DETAILS in the source distribution for details on how to use it.
--command-file file Same as --command-fd, except the commands are read out of file file
--allow-non-selfsigned-uid --no-allow-non-selfsigned-uid Allow the import and use of keys with user IDs which are not self- signed. This is not recommended, as a non self-signed user ID is trivial to forge. --no-allow-non-selfsigned-uid disables.
--allow-freeform-uid Disable all checks on the form of the user ID while generating a new one. This option should only be used in very special environments as it does not ensure the de-facto standard format of user IDs.
--ignore-time-conflict 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 makes these checks just a warning. See also --ignore-valid-from for timestamp issues on subkeys.
--ignore-valid-from GnuPG normally does not select and use subkeys created in the future.  This option allows the use of such keys and thus exhibits the pre-1.0.7 behaviour. You should not use this option unless there is some clock problem. See also --ignore-time-conflict for timestamp issues with signatures.
--ignore-crc-error The ASCII armor used by OpenPGP is protected by a CRC checksum against transmission errors. Occasionally the CRC gets mangled somewhere on the transmission channel but the actual content (which is protected by the OpenPGP protocol anyway) is still okay. This option allows GnuPG to ignore CRC errors.
--ignore-mdc-error This option changes a MDC integrity protection failure into a warning.  It is required to decrypt old messages which did not use an MDC.  It may also be useful if a message is partially garbled, but it is necessary to get as much data as possible out of that garbled message.  Be aware that a missing or failed MDC can be an indication of an attack.  Use with great caution; see also option --rfc2440.
--allow-weak-digest-algos Signatures made with known-weak digest algorithms are normally rejected with an ``invalid digest algorithm'' message.  This option allows the verification of signatures made with such weak algorithms.  MD5 is the only digest algorithm considered weak by default.  See also --weak-digest to reject other digest algorithms.
--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.  See also --allow-weak-digest-algos to disable rejection of weak digests.  MD5 is always considered weak, and does not need to be listed explicitly.
--allow-weak-key-signatures To avoid a minor risk of collision attacks on third-party key signatures made using SHA-1, those key signatures are considered invalid.  This options allows to override this restriction.
--no-default-keyring Do not add the default keyring to the list of keyrings. Note that GnuPG needs for almost all operations a keyring. Thus if you use this option and do not provide alternate keyrings via --keyring, then GnuPG will still use the default keyring.
--no-keyring Do not use any keyring at all.  This overrides the default and all options which specify keyrings.
--skip-verify Skip the signature verification step. This may be used to make the decryption faster if the signature verification is not needed.
--with-key-data Print key listings delimited by colons (like --with-colons) and print the public key data.
--list-signatures --list-sigs Same as --list-keys, but the signatures are listed too.  This command has the same effect as using --list-keys with --with-sig- list.  Note that in contrast to --check-signatures the key signatures are not verified.  This command can be used to create a list of signing keys missing in the local keyring; for example:
gpg --list-sigs --with-colons USERID | \ awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'
--fast-list-mode Changes the output of the list commands to work faster; this is achieved by leaving some parts empty. Some applications don't need the user ID and the trust information given in the listings. By using this options they can get a faster listing. The exact behaviour of this option may change in future versions.  If you are missing some information, don't use this option.
--no-literal This is not for normal use. Use the source to see for what it might be useful.
--set-filesize This is not for normal use. Use the source to see for what it might be useful.
--show-session-key Display the session key used for one message. See --override- session-key for the counterpart of this option.
We think that Key Escrow is a Bad Thing; however the user should have the freedom to decide whether to go to prison or to reveal the content of one specific message without compromising all messages ever encrypted for one secret key.
You can also use this option if you receive an encrypted message which is abusive or offensive, to prove to the administrators of the messaging system that the ciphertext transmitted corresponds to an inappropriate plaintext so they can take action against the offending user.
--override-session-key string --override-session-key-fd fd Don't use the public key but the session key string respective the session key taken from the first line read from file descriptor fd.  The format of this string is the same as the one printed by --show-session-key. This option is normally not used but comes handy in case someone forces you to reveal the content of an encrypted message; using this option you can do this without handing out the secret key.  Note that using --override-session- key may reveal the session key to all local users via the global process table.  Often it is useful to combine this option with --no-keyring.
--ask-sig-expire --no-ask-sig-expire When making a data signature, prompt for an expiration time. If this option is not specified, the expiration time set via --default-sig-expire is used. --no-ask-sig-expire disables this option.
--default-sig-expire The default expiration time to use for signature expiration. Valid values are "0" for no expiration, a number followed by the letter d (for days), w (for weeks), m (for months), or y (for years) (for example "2m" for two months, or "5y" for five years), or an absolute date in the form YYYY-MM-DD. Defaults to "0".
--ask-cert-expire --no-ask-cert-expire When making a key signature, prompt for an expiration time. If this option is not specified, the expiration time set via --default-cert-expire is used. --no-ask-cert-expire disables this option.
--default-cert-expire The default expiration time to use for key signature expiration. Valid values are "0" for no expiration, a number followed by the letter d (for days), w (for weeks), m (for months), or y (for years) (for example "2m" for two months, or "5y" for five years), or an absolute date in the form YYYY-MM-DD. Defaults to "0".
--default-new-key-algo string This option can be used to change the default algorithms for key generation. The string is similar to the arguments required for the command --quick-add-key but slightly different.  For example the current default of "rsa2048/cert,sign+rsa2048/encr" (or "rsa3072") can be changed to the value of what we currently call future default, which is "ed25519/cert,sign+cv25519/encr".  You need to consult the source code to learn the details.  Note that the advanced key generation commands can always be used to specify a key algorithm directly.
--force-sign-key This option modifies the behaviour of the commands --quick-sign- key, --quick-lsign-key, and the "sign" sub-commands of --edit-key by forcing the creation of a key signature, even if one already exists.
--allow-secret-key-import This is an obsolete option and is not used anywhere.
--allow-multiple-messages
--no-allow-multiple-messages Allow processing of multiple OpenPGP messages contained in a single file or stream.  Some programs that call GPG are not prepared to deal with multiple messages being processed together, so this option defaults to no.  Note that versions of GPG prior to 1.4.7 always allowed multiple messages.  Future versions of GnUPG will remove this option.
Warning: Do not use this option unless you need it as a temporary workaround!
--enable-special-filenames 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.
--no-expensive-trust-checks Experimental use only.
--preserve-permissions Don't change the permissions of a secret keyring back to user read/write only. Use this option only if you really know what you are doing.
--default-preference-list string Set the list of default preferences to string. This preference list is used for new keys and becomes the default for "setpref" in the edit menu.
--default-keyserver-url name Set the default keyserver URL to name. This keyserver will be used as the keyserver URL when writing a new self-signature on a key, which includes key generation and changing preferences.
--list-config Display various internal configuration parameters of GnuPG. This option is intended for external programs that call GnuPG to perform tasks, and is thus not generally useful. See the file ‘doc/DETAILS’ in the source distribution for the details of which configuration items may be listed. --list-config is only usable with --with-colons set.
--list-gcrypt-config Display various internal configuration parameters of Libgcrypt.
--gpgconf-list This command is similar to --list-config but in general only internally used by the gpgconf tool.
--gpgconf-test This is more or less dummy action.  However it parses the configuration file and returns with failure if the configuration file would prevent gpg from startup.  Thus it may be used to run a syntax check on the configuration file.
--show-photos --no-show-photos Causes --list-keys, --list-signatures, --list-public-keys, --list- secret-keys, and verifying a signature to also display the photo ID attached to the key, if any. See also --photo-viewer. These options are deprecated. Use --list-options [no-]show-photos and/or --verify-options [no-]show-photos instead.
--show-keyring Display the keyring name at the head of key listings to show which keyring a given key resides on. This option is deprecated: use --list-options [no-]show-keyring instead.
--always-trust Identical to --trust-model always. This option is deprecated.
--show-notation --no-show-notation Show signature notations in the --list-signatures or --check- signatures listings as well as when verifying a signature with a notation in it. These options are deprecated. Use --list-options [no-]show-notation and/or --verify-options [no-]show-notation instead.
--show-policy-url --no-show-policy-url Show policy URLs in the --list-signatures or --check-signatures listings as well as when verifying a signature with a policy URL in it. These options are deprecated. Use --list-options [no-]show- policy-url and/or --verify-options [no-]show-policy-url instead.
gpg -se -r Bob file sign and encrypt for user Bob
gpg --clear-sign file make a cleartext signature
gpg -sb file make a detached signature
gpg -u 0x12345678 -sb file make a detached signature with the key 0x12345678
gpg --list-keys user_ID show keys
gpg --fingerprint user_ID show fingerprint
gpg --verify pgpfile gpg --verify sigfile [datafile] Verify the signature of the file but do not output the data unless requested.  The second form is used for detached signatures, where sigfile is the detached signature (either ASCII armored or binary) and datafile are the signed data; if this is not given, the name of the file holding the signed data is constructed by cutting off the extension (".asc" or ".sig") of sigfile or by asking the user for the filename.  If the option --output is also used the signed data is written to the file specified by that option; use - to write the signed data to stdout.
There are different ways to specify a user ID to GnuPG.  Some of them are only valid for gpg others are only good for gpgsm.  Here is the entire list of ways to specify a key: