git-credential(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | TYPICAL USE OF GIT CREDENTIAL | INPUT/OUTPUT FORMAT | CAPABILITY INPUT/OUTPUT FORMAT | GIT | COLOPHON

GIT-CREDENTIAL(1)              Git Manual              GIT-CREDENTIAL(1)

NAME         top

       git-credential - Retrieve and store user credentials

SYNOPSIS         top

       'git credential' (fill|approve|reject|capability)

DESCRIPTION         top

       Git has an internal interface for storing and retrieving
       credentials from system-specific helpers, as well as prompting
       the user for usernames and passwords. The git-credential command
       exposes this interface to scripts which may want to retrieve,
       store, or prompt for credentials in the same manner as Git. The
       design of this scriptable interface models the internal C API;
       see credential.h for more background on the concepts.

       git-credential takes an "action" option on the command-line (one
       of fill, approve, or reject) and reads a credential description
       on stdin (see INPUT/OUTPUT FORMAT).

       If the action is fill, git-credential will attempt to add
       "username" and "password" attributes to the description by
       reading config files, by contacting any configured credential
       helpers, or by prompting the user. The username and password
       attributes of the credential description are then printed to
       stdout together with the attributes already provided.

       If the action is approve, git-credential will send the
       description to any configured credential helpers, which may store
       the credential for later use.

       If the action is reject, git-credential will send the description
       to any configured credential helpers, which may erase any stored
       credentials matching the description.

       If the action is capability, git-credential will announce any
       capabilities it supports to standard output.

       If the action is approve or reject, no output should be emitted.

TYPICAL USE OF GIT CREDENTIAL         top

       An application using git-credential will typically use git
       credential following these steps:

        1. Generate a credential description based on the context.

           For example, if we want a password for
           https://example.com/foo.git , we might generate the following
           credential description (don’t forget the blank line at the
           end; it tells git credential that the application finished
           feeding all the information it has):

               protocol=https
               host=example.com
               path=foo.git

        2. Ask git-credential to give us a username and password for
           this description. This is done by running git credential
           fill, feeding the description from step (1) to its standard
           input. The complete credential description (including the
           credential per se, i.e. the login and password) will be
           produced on standard output, like:

               protocol=https
               host=example.com
               username=bob
               password=secr3t

           In most cases, this means the attributes given in the input
           will be repeated in the output, but Git may also modify the
           credential description, for example by removing the path
           attribute when the protocol is HTTP(s) and
           credential.useHttpPath is false.

           If the git credential knew about the password, this step may
           not have involved the user actually typing this password (the
           user may have typed a password to unlock the keychain
           instead, or no user interaction was done if the keychain was
           already unlocked) before it returned password=secr3t.

        3. Use the credential (e.g., access the URL with the username
           and password from step (2)), and see if it’s accepted.

        4. Report on the success or failure of the password. If the
           credential allowed the operation to complete successfully,
           then it can be marked with an "approve" action to tell git
           credential to reuse it in its next invocation. If the
           credential was rejected during the operation, use the
           "reject" action so that git credential will ask for a new
           password in its next invocation. In either case, git
           credential should be fed with the credential description
           obtained from step (2) (which also contains the fields
           provided in step (1)).

INPUT/OUTPUT FORMAT         top

       git credential reads and/or writes (depending on the action used)
       credential information in its standard input/output. This
       information can correspond either to keys for which git
       credential will obtain the login information (e.g. host,
       protocol, path), or to the actual credential data to be obtained
       (username/password).

       The credential is split into a set of named attributes, with one
       attribute per line. Each attribute is specified by a key-value
       pair, separated by an = (equals) sign, followed by a newline.

       The key may contain any bytes except =, newline, or NUL. The
       value may contain any bytes except newline or NUL. A line,
       including the trailing newline, may not exceed 65535 bytes in
       order to allow implementations to parse efficiently.

       Attributes with keys that end with C-style array brackets [] can
       have multiple values. Each instance of a multi-valued attribute
       forms an ordered list of values - the order of the repeated
       attributes defines the order of the values. An empty multi-valued
       attribute (key[]=\n) acts to clear any previous entries and reset
       the list.

       In all cases, all bytes are treated as-is (i.e., there is no
       quoting, and one cannot transmit a value with newline or NUL in
       it). The list of attributes is terminated by a blank line or
       end-of-file.

       Git understands the following attributes:

       protocol
           The protocol over which the credential will be used (e.g.,
           https).

       host
           The remote hostname for a network credential. This includes
           the port number if one was specified (e.g.,
           "example.com:8088").

       path
           The path with which the credential will be used. E.g., for
           accessing a remote https repository, this will be the
           repository’s path on the server.

       username
           The credential’s username, if we already have one (e.g., from
           a URL, the configuration, the user, or from a previously run
           helper).

       password
           The credential’s password, if we are asking it to be stored.

       password_expiry_utc
           Generated passwords such as an OAuth access token may have an
           expiry date. When reading credentials from helpers, git
           credential fill ignores expired passwords. Represented as
           Unix time UTC, seconds since 1970.

       oauth_refresh_token
           An OAuth refresh token may accompany a password that is an
           OAuth access token. Helpers must treat this attribute as
           confidential like the password attribute. Git itself has no
           special behaviour for this attribute.

       url
           When this special attribute is read by git credential, the
           value is parsed as a URL and treated as if its constituent
           parts were read (e.g., url=https://example.com would behave
           as if protocol=https and host=example.com had been provided).
           This can help callers avoid parsing URLs themselves.

           Note that specifying a protocol is mandatory and if the URL
           doesn’t specify a hostname (e.g., "cert:///path/to/file") the
           credential will contain a hostname attribute whose value is
           an empty string.

           Components which are missing from the URL (e.g., there is no
           username in the example above) will be left unset.

       authtype
           This indicates that the authentication scheme in question
           should be used. Common values for HTTP and HTTPS include
           basic, bearer, and digest, although the latter is insecure
           and should not be used. If credential is used, this may be
           set to an arbitrary string suitable for the protocol in
           question (usually HTTP).

           This value should not be sent unless the appropriate
           capability (see below) is provided on input.

       credential
           The pre-encoded credential, suitable for the protocol in
           question (usually HTTP). If this key is sent, authtype is
           mandatory, and username and password are not used. For HTTP,
           Git concatenates the authtype value and this value with a
           single space to determine the Authorization header.

           This value should not be sent unless the appropriate
           capability (see below) is provided on input.

       ephemeral
           This boolean value indicates, if true, that the value in the
           credential field should not be saved by the credential helper
           because its usefulness is limited in time. For example, an
           HTTP Digest credential value is computed using a nonce and
           reusing it will not result in successful authentication. This
           may also be used for situations with short duration (e.g.,
           24-hour) credentials. The default value is false.

           The credential helper will still be invoked with store or
           erase so that it can determine whether the operation was
           successful.

           This value should not be sent unless the appropriate
           capability (see below) is provided on input.

       state[]
           This value provides an opaque state that will be passed back
           to this helper if it is called again. Each different
           credential helper may specify this once. The value should
           include a prefix unique to the credential helper and should
           ignore values that don’t match its prefix.

           This value should not be sent unless the appropriate
           capability (see below) is provided on input.

       continue
           This is a boolean value, which, if enabled, indicates that
           this authentication is a non-final part of a multistage
           authentication step. This is common in protocols such as NTLM
           and Kerberos, where two rounds of client authentication are
           required, and setting this flag allows the credential helper
           to implement the multistage authentication step. This flag
           should only be sent if a further stage is required; that is,
           if another round of authentication is expected.

           This value should not be sent unless the appropriate
           capability (see below) is provided on input. This attribute
           is one-way from a credential helper to pass information to
           Git (or other programs invoking git credential).

       wwwauth[]
           When an HTTP response is received by Git that includes one or
           more WWW-Authenticate authentication headers, these will be
           passed by Git to credential helpers.

           Each WWW-Authenticate header value is passed as a
           multi-valued attribute wwwauth[], where the order of the
           attributes is the same as they appear in the HTTP response.
           This attribute is one-way from Git to pass additional
           information to credential helpers.

       capability[]
           This signals that Git, or the helper, as appropriate,
           supports the capability in question. This can be used to
           provide better, more specific data as part of the protocol. A
           capability[] directive must precede any value depending on it
           and these directives should be the first item announced in
           the protocol.

           There are two currently supported capabilities. The first is
           authtype, which indicates that the authtype, credential, and
           ephemeral values are understood. The second is state, which
           indicates that the state[] and continue values are
           understood.

           It is not obligatory to use the additional features just
           because the capability is supported, but they should not be
           provided without the capability.

       Unrecognised attributes and capabilities are silently discarded.

CAPABILITY INPUT/OUTPUT FORMAT         top

       For git credential capability, the format is slightly different.
       First, a version 0 announcement is made to indicate the current
       version of the protocol, and then each capability is announced
       with a line like capability authtype. Credential helpers may also
       implement this format, again with the capability argument.
       Additional lines may be added in the future; callers should
       ignore lines which they don’t understand.

       Because this is a new part of the credential helper protocol,
       older versions of Git, as well as some credential helpers, may
       not support it. If a non-zero exit status is received, or if the
       first line doesn’t start with the word version and a space,
       callers should assume that no capabilities are supported.

       The intention of this format is to differentiate it from the
       credential output in an unambiguous way. It is possible to use
       very simple credential helpers (e.g., inline shell scripts) which
       always produce identical output. Using a distinct format allows
       users to continue to use this syntax without having to worry
       about correctly implementing capability advertisements or
       accidentally confusing callers querying for capabilities.

GIT         top

       Part of the git(1) suite

COLOPHON         top

       This page is part of the git (Git distributed version control
       system) project.  Information about the project can be found at
       ⟨http://git-scm.com/⟩.  If you have a bug report for this manual
       page, see ⟨http://git-scm.com/community⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨https://github.com/git/git.git⟩ on 2024-06-14.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2024-06-12.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       [email protected]

Git 2.45.2.492.gd63586         2024-06-12              GIT-CREDENTIAL(1)

Pages that refer to this page: git(1)git-config(1)git-send-email(1)gitcredentials(7)