git credential <fill|approve|reject>
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 credential matching the description.
An application using git-credential will typically use git credential following these steps:
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
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.
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.
In both 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:
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.