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