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1 | gitcredentials(7) |
2 | ================= | |
3 | ||
4 | NAME | |
5 | ---- | |
2135e1ad | 6 | gitcredentials - Providing usernames and passwords to Git |
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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 | |
2de9b711 | 21 | the mechanisms Git uses to request these credentials, as well as some |
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22 | features to avoid inputting these credentials repeatedly. |
23 | ||
24 | REQUESTING CREDENTIALS | |
25 | ---------------------- | |
26 | ||
2de9b711 | 27 | Without any credential helpers defined, Git will try the following |
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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 | ||
da0005b8 | 35 | 2. Otherwise, if the `core.askPass` configuration variable is set, its |
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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 | ||
2de9b711 | 62 | Credential helpers, on the other hand, are external programs from which Git can |
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63 | request both usernames and passwords; they typically interface with secure |
64 | storage provided by the OS or other programs. | |
65 | ||
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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 | ||
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74 | store:: |
75 | ||
76 | Store credentials indefinitely on disk. See | |
77 | linkgit:git-credential-store[1] for details. | |
78 | ||
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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, | |
2de9b711 | 82 | you can tell Git to use it by putting its name into the |
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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 | ||
2de9b711 | 98 | 3. Tell Git to use it. |
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99 | + |
100 | ------------------------------------------- | |
101 | $ git config --global credential.helper foo | |
102 | ------------------------------------------- | |
103 | ||
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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 | ||
2de9b711 | 112 | For instance, imagine we are accessing `https://example.com/foo.git`. When Git |
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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 | ||
2de9b711 | 131 | because the hostnames differ. Nor would it match `foo.example.com`; Git |
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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 | |
46fd7b39 | 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. | |
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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 | ||
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144 | |
145 | CONFIGURATION OPTIONS | |
146 | --------------------- | |
147 | ||
148 | Options for a credential context can be configured either in | |
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149 | `credential.*` (which applies to all credentials), or |
150 | `credential.<url>.*`, where <url> matches the context as described | |
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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. | |
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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). | |
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173 | |
174 | username:: | |
175 | ||
176 | A default username, if one is not provided in the URL. | |
177 | ||
178 | useHttpPath:: | |
179 | ||
2de9b711 | 180 | By default, Git does not consider the "path" component of an http URL |
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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 | |
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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" | |
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219 | [credential] |
220 | helper = foo | |
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221 | |
222 | # same as above, but pass an argument to the helper | |
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223 | [credential] |
224 | helper = "foo --bar=baz" | |
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225 | |
226 | # the arguments are parsed by the shell, so use shell | |
227 | # quoting if necessary | |
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228 | [credential] |
229 | helper = "foo --bar='whitespace arg'" | |
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230 | |
231 | # you can also use an absolute path, which will not use the git wrapper | |
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232 | [credential] |
233 | helper = "/path/to/my/helper --with-arguments" | |
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234 | |
235 | # or you can specify your own shell snippet | |
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236 | [credential "https://example.com"] |
237 | username = your_user | |
238 | helper = "!f() { test \"$1\" = get && echo \"password=$(cat $HOME/.secret)\"; }; f" | |
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239 | ---------------------------------------------------- |
240 | ||
241 | Generally speaking, rule (3) above is the simplest for users to specify. | |
242 | Authors of credential helpers should make an effort to assist their | |
243 | users by naming their program "git-credential-$NAME", and putting it in | |
244 | the `$PATH` or `$GIT_EXEC_PATH` during installation, which will allow a | |
245 | user to enable it with `git config credential.helper $NAME`. | |
246 | ||
247 | When a helper is executed, it will have one "operation" argument | |
248 | appended to its command line, which is one of: | |
249 | ||
250 | `get`:: | |
251 | ||
252 | Return a matching credential, if any exists. | |
253 | ||
254 | `store`:: | |
255 | ||
256 | Store the credential, if applicable to the helper. | |
257 | ||
258 | `erase`:: | |
259 | ||
260 | Remove a matching credential, if any, from the helper's storage. | |
261 | ||
262 | The details of the credential will be provided on the helper's stdin | |
263 | stream. The exact format is the same as the input/output format of the | |
264 | `git credential` plumbing command (see the section `INPUT/OUTPUT | |
265 | FORMAT` in linkgit:git-credential[1] for a detailed specification). | |
266 | ||
267 | For a `get` operation, the helper should produce a list of attributes on | |
268 | stdout in the same format (see linkgit:git-credential[1] for common | |
269 | attributes). A helper is free to produce a subset, or even no values at | |
270 | all if it has nothing useful to provide. Any provided attributes will | |
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271 | overwrite those already known about by Git's credential subsystem. |
272 | ||
273 | While it is possible to override all attributes, well behaving helpers | |
274 | should refrain from doing so for any attribute other than username and | |
275 | password. | |
276 | ||
277 | If a helper outputs a `quit` attribute with a value of `true` or `1`, | |
278 | no further helpers will be consulted, nor will the user be prompted | |
279 | (if no credential has been provided, the operation will then fail). | |
280 | ||
281 | Similarly, no more helpers will be consulted once both username and | |
282 | password had been provided. | |
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283 | |
284 | For a `store` or `erase` operation, the helper's output is ignored. | |
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285 | |
286 | If a helper fails to perform the requested operation or needs to notify | |
287 | the user of a potential issue, it may write to stderr. | |
288 | ||
289 | If it does not support the requested operation (e.g., a read-only store), | |
290 | it should silently ignore the request. | |
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291 | |
292 | If a helper receives any other operation, it should silently ignore the | |
293 | request. This leaves room for future operations to be added (older | |
294 | helpers will just ignore the new requests). | |
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295 | |
296 | GIT | |
297 | --- | |
298 | Part of the linkgit:git[1] suite |