Documentation/gitcredentials.txt

   1 gitcredentials(7)
   2 =================
   3
   4 NAME
   5 ----
   6 gitcredentials - Providing usernames and passwords to Git
   7
   8 SYNOPSIS
   9 --------
  10 ------------------
  11 git config credential.https://example.com.username myusername
  12 git config credential.helper "$helper $options"
  13 ------------------
  14
  15 DESCRIPTION
  16 -----------
  17
  18 Git will sometimes need credentials from the user in order to perform
  19 operations; for example, it may need to ask for a username and password
  20 in order to access a remote repository over HTTP. Some remotes accept
  21 a personal access token or OAuth access token as a password. This
  22 manual describes the mechanisms Git uses to request these credentials,
  23 as well as some features to avoid inputting these credentials repeatedly.
  24
  25 REQUESTING CREDENTIALS
  26 ----------------------
  27
  28 Without any credential helpers defined, Git will try the following
  29 strategies to ask the user for usernames and passwords:
  30
  31 1. If the `GIT_ASKPASS` environment variable is set, the program
  32    specified by the variable is invoked. A suitable prompt is provided
  33    to the program on the command line, and the user's input is read
  34    from its standard output.
  35
  36 2. Otherwise, if the `core.askPass` configuration variable is set, its
  37    value is used as above.
  38
  39 3. Otherwise, if the `SSH_ASKPASS` environment variable is set, its
  40    value is used as above.
  41
  42 4. Otherwise, the user is prompted on the terminal.
  43
  44 AVOIDING REPETITION
  45 -------------------
  46
  47 It can be cumbersome to input the same credentials over and over.  Git
  48 provides two methods to reduce this annoyance:
  49
  50 1. Static configuration of usernames for a given authentication context.
  51
  52 2. Credential helpers to cache or store passwords, or to interact with
  53    a system password wallet or keychain.
  54
  55 The first is simple and appropriate if you do not have secure storage available
  56 for a password. It is generally configured by adding this to your config:
  57
  58 ---------------------------------------
  59 [credential "https://example.com"]
  60         username = me
  61 ---------------------------------------
  62
  63 Credential helpers, on the other hand, are external programs from which Git can
  64 request both usernames and passwords; they typically interface with secure
  65 storage provided by the OS or other programs. Alternatively, a
  66 credential-generating helper might generate credentials for certain servers via
  67 some API.
  68
  69 To use a helper, you must first select one to use. Git currently
  70 includes the following helpers:
  71
  72 cache::
  73
  74         Cache credentials in memory for a short period of time. See
  75         linkgit:git-credential-cache[1] for details.
  76
  77 store::
  78
  79         Store credentials indefinitely on disk. See
  80         linkgit:git-credential-store[1] for details.
  81
  82 You may also have third-party helpers installed; search for
  83 `credential-*` in the output of `git help -a`, and consult the
  84 documentation of individual helpers.  Once you have selected a helper,
  85 you can tell Git to use it by putting its name into the
  86 credential.helper variable.
  87
  88 1. Find a helper.
  89 +
  90 -------------------------------------------
  91 $ git help -a | grep credential-
  92 credential-foo
  93 -------------------------------------------
  94
  95 2. Read its description.
  96 +
  97 -------------------------------------------
  98 $ git help credential-foo
  99 -------------------------------------------
 100
 101 3. Tell Git to use it.
 102 +
 103 -------------------------------------------
 104 $ git config --global credential.helper foo
 105 -------------------------------------------
 106
 107 === Available helpers
 108
 109 The community maintains a comprehensive list of Git credential helpers at
 110 https://git-scm.com/doc/credential-helpers.
 111
 112 === OAuth
 113
 114 An alternative to inputting passwords or personal access tokens is to use an
 115 OAuth credential helper. Initial authentication opens a browser window to the
 116 host. Subsequent authentication happens in the background. Many popular Git
 117 hosts support OAuth.
 118
 119 CREDENTIAL CONTEXTS
 120 -------------------
 121
 122 Git considers each credential to have a context defined by a URL. This context
 123 is used to look up context-specific configuration, and is passed to any
 124 helpers, which may use it as an index into secure storage.
 125
 126 For instance, imagine we are accessing `https://example.com/foo.git`. When Git
 127 looks into a config file to see if a section matches this context, it will
 128 consider the two a match if the context is a more-specific subset of the
 129 pattern in the config file. For example, if you have this in your config file:
 130
 131 --------------------------------------
 132 [credential "https://example.com"]
 133         username = foo
 134 --------------------------------------
 135
 136 then we will match: both protocols are the same, both hosts are the same, and
 137 the "pattern" URL does not care about the path component at all. However, this
 138 context would not match:
 139
 140 --------------------------------------
 141 [credential "https://kernel.org"]
 142         username = foo
 143 --------------------------------------
 144
 145 because the hostnames differ. Nor would it match `foo.example.com`; Git
 146 compares hostnames exactly, without considering whether two hosts are part of
 147 the same domain. Likewise, a config entry for `http://example.com` would not
 148 match: Git compares the protocols exactly.  However, you may use wildcards in
 149 the domain name and other pattern matching techniques as with the `http.<URL>.*`
 150 options.
 151
 152 If the "pattern" URL does include a path component, then this too must match
 153 exactly: the context `https://example.com/bar/baz.git` will match a config
 154 entry for `https://example.com/bar/baz.git` (in addition to matching the config
 155 entry for `https://example.com`) but will not match a config entry for
 156 `https://example.com/bar`.
 157
 158
 159 CONFIGURATION OPTIONS
 160 ---------------------
 161
 162 Options for a credential context can be configured either in
 163 `credential.*` (which applies to all credentials), or
 164 `credential.<URL>.*`, where <URL> matches the context as described
 165 above.
 166
 167 The following options are available in either location:
 168
 169 helper::
 170
 171         The name of an external credential helper, and any associated options.
 172         If the helper name is not an absolute path, then the string `git
 173         credential-` is prepended. The resulting string is executed by the
 174         shell (so, for example, setting this to `foo --option=bar` will execute
 175         `git credential-foo --option=bar` via the shell. See the manual of
 176         specific helpers for examples of their use.
 177 +
 178 If there are multiple instances of the `credential.helper` configuration
 179 variable, each helper will be tried in turn, and may provide a username,
 180 password, or nothing. Once Git has acquired both a username and a
 181 non-expired password, no more helpers will be tried.
 182 +
 183 If `credential.helper` is configured to the empty string, this resets
 184 the helper list to empty (so you may override a helper set by a
 185 lower-priority config file by configuring the empty-string helper,
 186 followed by whatever set of helpers you would like).
 187
 188 username::
 189
 190         A default username, if one is not provided in the URL.
 191
 192 useHttpPath::
 193
 194         By default, Git does not consider the "path" component of an http URL
 195         to be worth matching via external helpers. This means that a credential
 196         stored for `https://example.com/foo.git` will also be used for
 197         `https://example.com/bar.git`. If you do want to distinguish these
 198         cases, set this option to `true`.
 199
 200
 201 CUSTOM HELPERS
 202 --------------
 203
 204 You can write your own custom helpers to interface with any system in
 205 which you keep credentials.
 206
 207 Credential helpers are programs executed by Git to fetch or save
 208 credentials from and to long-term storage (where "long-term" is simply
 209 longer than a single Git process; e.g., credentials may be stored
 210 in-memory for a few minutes, or indefinitely on disk).
 211
 212 Each helper is specified by a single string in the configuration
 213 variable `credential.helper` (and others, see linkgit:git-config[1]).
 214 The string is transformed by Git into a command to be executed using
 215 these rules:
 216
 217   1. If the helper string begins with "!", it is considered a shell
 218      snippet, and everything after the "!" becomes the command.
 219
 220   2. Otherwise, if the helper string begins with an absolute path, the
 221      verbatim helper string becomes the command.
 222
 223   3. Otherwise, the string "git credential-" is prepended to the helper
 224      string, and the result becomes the command.
 225
 226 The resulting command then has an "operation" argument appended to it
 227 (see below for details), and the result is executed by the shell.
 228
 229 Here are some example specifications:
 230
 231 ----------------------------------------------------
 232 # run "git credential-foo"
 233 [credential]
 234         helper = foo
 235
 236 # same as above, but pass an argument to the helper
 237 [credential]
 238         helper = "foo --bar=baz"
 239
 240 # the arguments are parsed by the shell, so use shell
 241 # quoting if necessary
 242 [credential]
 243         helper = "foo --bar='whitespace arg'"
 244
 245 # you can also use an absolute path, which will not use the git wrapper
 246 [credential]
 247         helper = "/path/to/my/helper --with-arguments"
 248
 249 # or you can specify your own shell snippet
 250 [credential "https://example.com"]
 251         username = your_user
 252         helper = "!f() { test \"$1\" = get && echo \"password=$(cat $HOME/.secret)\"; }; f"
 253 ----------------------------------------------------
 254
 255 Generally speaking, rule (3) above is the simplest for users to specify.
 256 Authors of credential helpers should make an effort to assist their
 257 users by naming their program "git-credential-$NAME", and putting it in
 258 the `$PATH` or `$GIT_EXEC_PATH` during installation, which will allow a
 259 user to enable it with `git config credential.helper $NAME`.
 260
 261 When a helper is executed, it will have one "operation" argument
 262 appended to its command line, which is one of:
 263
 264 `get`::
 265
 266         Return a matching credential, if any exists.
 267
 268 `store`::
 269
 270         Store the credential, if applicable to the helper.
 271
 272 `erase`::
 273
 274         Remove matching credentials, if any, from the helper's storage.
 275
 276 The details of the credential will be provided on the helper's stdin
 277 stream. The exact format is the same as the input/output format of the
 278 `git credential` plumbing command (see the section `INPUT/OUTPUT
 279 FORMAT` in linkgit:git-credential[1] for a detailed specification).
 280
 281 For a `get` operation, the helper should produce a list of attributes on
 282 stdout in the same format (see linkgit:git-credential[1] for common
 283 attributes). A helper is free to produce a subset, or even no values at
 284 all if it has nothing useful to provide. Any provided attributes will
 285 overwrite those already known about by Git's credential subsystem.
 286 Unrecognised attributes are silently discarded.
 287
 288 While it is possible to override all attributes, well behaving helpers
 289 should refrain from doing so for any attribute other than username and
 290 password.
 291
 292 If a helper outputs a `quit` attribute with a value of `true` or `1`,
 293 no further helpers will be consulted, nor will the user be prompted
 294 (if no credential has been provided, the operation will then fail).
 295
 296 Similarly, no more helpers will be consulted once both username and
 297 password had been provided.
 298
 299 For a `store` or `erase` operation, the helper's output is ignored.
 300
 301 If a helper fails to perform the requested operation or needs to notify
 302 the user of a potential issue, it may write to stderr.
 303
 304 If it does not support the requested operation (e.g., a read-only store
 305 or generator), it should silently ignore the request.
 306
 307 If a helper receives any other operation, it should silently ignore the
 308 request. This leaves room for future operations to be added (older
 309 helpers will just ignore the new requests).
 310
 311 GIT
 312 ---
 313 Part of the linkgit:git[1] suite