4.2.3 Input and Output

--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.

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)

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.