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.  However, you may use wildcards in
 135 the domain name and other pattern matching techniques as with the `http.<url>.*`
 136 options.
 137
 138 If the "pattern" URL does include a path component, then this too must match
 139 exactly: the context `https://example.com/bar/baz.git` will match a config
 140 entry for `https://example.com/bar/baz.git` (in addition to matching the config
 141 entry for `https://example.com`) but will not match a config entry for
 142 `https://example.com/bar`.
 143
 144
 145 CONFIGURATION OPTIONS
 146 ---------------------
 147
 148 Options for a credential context can be configured either in
 149 `credential.*` (which applies to all credentials), or
 150 `credential.<url>.*`, where <url> matches the context as described
 151 above.
 152
 153 The following options are available in either location:
 154
 155 helper::
 156
 157         The name of an external credential helper, and any associated options.
 158         If the helper name is not an absolute path, then the string `git
 159         credential-` is prepended. The resulting string is executed by the
 160         shell (so, for example, setting this to `foo --option=bar` will execute
 161         `git credential-foo --option=bar` via the shell. See the manual of
 162         specific helpers for examples of their use.
 163 +
 164 If there are multiple instances of the `credential.helper` configuration
 165 variable, each helper will be tried in turn, and may provide a username,
 166 password, or nothing. Once Git has acquired both a username and a
 167 password, no more helpers will be tried.
 168 +
 169 If `credential.helper` is configured to the empty string, this resets
 170 the helper list to empty (so you may override a helper set by a
 171 lower-priority config file by configuring the empty-string helper,
 172 followed by whatever set of helpers you would like).
 173
 174 username::
 175
 176         A default username, if one is not provided in the URL.
 177
 178 useHttpPath::
 179
 180         By default, Git does not consider the "path" component of an http URL
 181         to be worth matching via external helpers. This means that a credential
 182         stored for `https://example.com/foo.git` will also be used for
 183         `https://example.com/bar.git`. If you do want to distinguish these
 184         cases, set this option to `true`.
 185
 186
 187 CUSTOM HELPERS
 188 --------------
 189
 190 You can write your own custom helpers to interface with any system in
 191 which you keep credentials.
 192
 193 Credential helpers are programs executed by Git to fetch or save
 194 credentials from and to long-term storage (where "long-term" is simply
 195 longer than a single Git process; e.g., credentials may be stored
 196 in-memory for a few minutes, or indefinitely on disk).
 197
 198 Each helper is specified by a single string in the configuration
 199 variable `credential.helper` (and others, see linkgit:git-config[1]).
 200 The string is transformed by Git into a command to be executed using
 201 these rules:
 202
 203   1. If the helper string begins with "!", it is considered a shell
 204      snippet, and everything after the "!" becomes the command.
 205
 206   2. Otherwise, if the helper string begins with an absolute path, the
 207      verbatim helper string becomes the command.
 208
 209   3. Otherwise, the string "git credential-" is prepended to the helper
 210      string, and the result becomes the command.
 211
 212 The resulting command then has an "operation" argument appended to it
 213 (see below for details), and the result is executed by the shell.
 214
 215 Here are some example specifications:
 216
 217 ----------------------------------------------------
 218 # run "git credential-foo"
 219 foo
 220
 221 # same as above, but pass an argument to the helper
 222 foo --bar=baz
 223
 224 # the arguments are parsed by the shell, so use shell
 225 # quoting if necessary
 226 foo --bar="whitespace arg"
 227
 228 # you can also use an absolute path, which will not use the git wrapper
 229 /path/to/my/helper --with-arguments
 230
 231 # or you can specify your own shell snippet
 232 !f() { echo "password=`cat $HOME/.secret`"; }; f
 233 ----------------------------------------------------
 234
 235 Generally speaking, rule (3) above is the simplest for users to specify.
 236 Authors of credential helpers should make an effort to assist their
 237 users by naming their program "git-credential-$NAME", and putting it in
 238 the `$PATH` or `$GIT_EXEC_PATH` during installation, which will allow a
 239 user to enable it with `git config credential.helper $NAME`.
 240
 241 When a helper is executed, it will have one "operation" argument
 242 appended to its command line, which is one of:
 243
 244 `get`::
 245
 246         Return a matching credential, if any exists.
 247
 248 `store`::
 249
 250         Store the credential, if applicable to the helper.
 251
 252 `erase`::
 253
 254         Remove a matching credential, if any, from the helper's storage.
 255
 256 The details of the credential will be provided on the helper's stdin
 257 stream. The exact format is the same as the input/output format of the
 258 `git credential` plumbing command (see the section `INPUT/OUTPUT
 259 FORMAT` in linkgit:git-credential[1] for a detailed specification).
 260
 261 For a `get` operation, the helper should produce a list of attributes on
 262 stdout in the same format (see linkgit:git-credential[1] for common
 263 attributes). A helper is free to produce a subset, or even no values at
 264 all if it has nothing useful to provide. Any provided attributes will
 265 overwrite those already known about by Git.  If a helper outputs a
 266 `quit` attribute with a value of `true` or `1`, no further helpers will
 267 be consulted, nor will the user be prompted (if no credential has been
 268 provided, the operation will then fail).
 269
 270 For a `store` or `erase` operation, the helper's output is ignored.
 271 If it fails to perform the requested operation, it may complain to
 272 stderr to inform the user. If it does not support the requested
 273 operation (e.g., a read-only store), it should silently ignore the
 274 request.
 275
 276 If a helper receives any other operation, it should silently ignore the
 277 request. This leaves room for future operations to be added (older
 278 helpers will just ignore the new requests).
 279
 280 GIT
 281 ---
 282 Part of the linkgit:git[1] suite