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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
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
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
credential matching the description.
If the action is
reject, no output should be emitted.
An application using git-credential will typically use
credential following these steps:
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 credentialthat the application finished feeding all the information it has):
protocol=https host=example.com path=foo.git
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
pathattribute when the protocol is HTTP(s) and
git credentialknew 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
Use the credential (e.g., access the URL with the username and password from step (2)), and see if it’s accepted.
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 credentialto reuse it in its next invocation. If the credential was rejected during the operation, use the "reject" action so that
git credentialwill ask for a new password in its next invocation. In either case,
git credentialshould be fed with the credential description obtained from step (2) (which also contain the ones provided in step (1)).
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.
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 (
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:
The protocol over which the credential will be used (e.g.,
The remote hostname for a network credential. This includes the port number if one was specified (e.g., "example.com:8088").
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.
The credential’s username, if we already have one (e.g., from a URL, the configuration, the user, or from a previously run helper).
The credential’s password, if we are asking it to be stored.
Generated passwords such as an OAuth access token may have an expiry date. When reading credentials from helpers,
git credential fillignores expired passwords. Represented as Unix time UTC, seconds since 1970.
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.
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.comwould behave as if
host=example.comhad 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.
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.
Unrecognised attributes are silently discarded.
Part of the git suite