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
 108 CREDENTIAL CONTEXTS
 109 -------------------
 110
 111 Git considers each credential to have a context defined by a URL. This context
 112 is used to look up context-specific configuration, and is passed to any
 113 helpers, which may use it as an index into secure storage.
 114
 115 For instance, imagine we are accessing `https://example.com/foo.git`. When Git
 116 looks into a config file to see if a section matches this context, it will
 117 consider the two a match if the context is a more-specific subset of the
 118 pattern in the config file. For example, if you have this in your config file:
 119
 120 --------------------------------------
 121 [credential "https://example.com"]
 122         username = foo
 123 --------------------------------------
 124
 125 then we will match: both protocols are the same, both hosts are the same, and
 126 the "pattern" URL does not care about the path component at all. However, this
 127 context would not match:
 128
 129 --------------------------------------
 130 [credential "https://kernel.org"]
 131         username = foo
 132 --------------------------------------
 133
 134 because the hostnames differ. Nor would it match `foo.example.com`; Git
 135 compares hostnames exactly, without considering whether two hosts are part of
 136 the same domain. Likewise, a config entry for `http://example.com` would not
 137 match: Git compares the protocols exactly.  However, you may use wildcards in
 138 the domain name and other pattern matching techniques as with the `http.<URL>.*`
 139 options.
 140
 141 If the "pattern" URL does include a path component, then this too must match
 142 exactly: the context `https://example.com/bar/baz.git` will match a config
 143 entry for `https://example.com/bar/baz.git` (in addition to matching the config
 144 entry for `https://example.com`) but will not match a config entry for
 145 `https://example.com/bar`.
 146
 147
 148 CONFIGURATION OPTIONS
 149 ---------------------
 150
 151 Options for a credential context can be configured either in
 152 `credential.*` (which applies to all credentials), or
 153 `credential.<URL>.*`, where <URL> matches the context as described
 154 above.
 155
 156 The following options are available in either location:
 157
 158 helper::
 159
 160         The name of an external credential helper, and any associated options.
 161         If the helper name is not an absolute path, then the string `git
 162         credential-` is prepended. The resulting string is executed by the
 163         shell (so, for example, setting this to `foo --option=bar` will execute
 164         `git credential-foo --option=bar` via the shell. See the manual of
 165         specific helpers for examples of their use.
 166 +
 167 If there are multiple instances of the `credential.helper` configuration
 168 variable, each helper will be tried in turn, and may provide a username,
 169 password, or nothing. Once Git has acquired both a username and a
 170 non-expired password, no more helpers will be tried.
 171 +
 172 If `credential.helper` is configured to the empty string, this resets
 173 the helper list to empty (so you may override a helper set by a
 174 lower-priority config file by configuring the empty-string helper,
 175 followed by whatever set of helpers you would like).
 176
 177 username::
 178
 179         A default username, if one is not provided in the URL.
 180
 181 useHttpPath::
 182
 183         By default, Git does not consider the "path" component of an http URL
 184         to be worth matching via external helpers. This means that a credential
 185         stored for `https://example.com/foo.git` will also be used for
 186         `https://example.com/bar.git`. If you do want to distinguish these
 187         cases, set this option to `true`.
 188
 189
 190 CUSTOM HELPERS
 191 --------------
 192
 193 You can write your own custom helpers to interface with any system in
 194 which you keep credentials.
 195
 196 Credential helpers are programs executed by Git to fetch or save
 197 credentials from and to long-term storage (where "long-term" is simply
 198 longer than a single Git process; e.g., credentials may be stored
 199 in-memory for a few minutes, or indefinitely on disk).
 200
 201 Each helper is specified by a single string in the configuration
 202 variable `credential.helper` (and others, see linkgit:git-config[1]).
 203 The string is transformed by Git into a command to be executed using
 204 these rules:
 205
 206   1. If the helper string begins with "!", it is considered a shell
 207      snippet, and everything after the "!" becomes the command.
 208
 209   2. Otherwise, if the helper string begins with an absolute path, the
 210      verbatim helper string becomes the command.
 211
 212   3. Otherwise, the string "git credential-" is prepended to the helper
 213      string, and the result becomes the command.
 214
 215 The resulting command then has an "operation" argument appended to it
 216 (see below for details), and the result is executed by the shell.
 217
 218 Here are some example specifications:
 219
 220 ----------------------------------------------------
 221 # run "git credential-foo"
 222 [credential]
 223         helper = foo
 224
 225 # same as above, but pass an argument to the helper
 226 [credential]
 227         helper = "foo --bar=baz"
 228
 229 # the arguments are parsed by the shell, so use shell
 230 # quoting if necessary
 231 [credential]
 232         helper = "foo --bar='whitespace arg'"
 233
 234 # you can also use an absolute path, which will not use the git wrapper
 235 [credential]
 236         helper = "/path/to/my/helper --with-arguments"
 237
 238 # or you can specify your own shell snippet
 239 [credential "https://example.com"]
 240         username = your_user
 241         helper = "!f() { test \"$1\" = get && echo \"password=$(cat $HOME/.secret)\"; }; f"
 242 ----------------------------------------------------
 243
 244 Generally speaking, rule (3) above is the simplest for users to specify.
 245 Authors of credential helpers should make an effort to assist their
 246 users by naming their program "git-credential-$NAME", and putting it in
 247 the `$PATH` or `$GIT_EXEC_PATH` during installation, which will allow a
 248 user to enable it with `git config credential.helper $NAME`.
 249
 250 When a helper is executed, it will have one "operation" argument
 251 appended to its command line, which is one of:
 252
 253 `get`::
 254
 255         Return a matching credential, if any exists.
 256
 257 `store`::
 258
 259         Store the credential, if applicable to the helper.
 260
 261 `erase`::
 262
 263         Remove a matching credential, if any, from the helper's storage.
 264
 265 The details of the credential will be provided on the helper's stdin
 266 stream. The exact format is the same as the input/output format of the
 267 `git credential` plumbing command (see the section `INPUT/OUTPUT
 268 FORMAT` in linkgit:git-credential[1] for a detailed specification).
 269
 270 For a `get` operation, the helper should produce a list of attributes on
 271 stdout in the same format (see linkgit:git-credential[1] for common
 272 attributes). A helper is free to produce a subset, or even no values at
 273 all if it has nothing useful to provide. Any provided attributes will
 274 overwrite those already known about by Git's credential subsystem.
 275 Unrecognised attributes are silently discarded.
 276
 277 While it is possible to override all attributes, well behaving helpers
 278 should refrain from doing so for any attribute other than username and
 279 password.
 280
 281 If a helper outputs a `quit` attribute with a value of `true` or `1`,
 282 no further helpers will be consulted, nor will the user be prompted
 283 (if no credential has been provided, the operation will then fail).
 284
 285 Similarly, no more helpers will be consulted once both username and
 286 password had been provided.
 287
 288 For a `store` or `erase` operation, the helper's output is ignored.
 289
 290 If a helper fails to perform the requested operation or needs to notify
 291 the user of a potential issue, it may write to stderr.
 292
 293 If it does not support the requested operation (e.g., a read-only store
 294 or generator), it should silently ignore the request.
 295
 296 If a helper receives any other operation, it should silently ignore the
 297 request. This leaves room for future operations to be added (older
 298 helpers will just ignore the new requests).
 299
 300 GIT
 301 ---
 302 Part of the linkgit:git[1] suite