git-submodule: add support for --merge.
[git/git.git] / Documentation / git-submodule.txt
1 git-submodule(1)
2 ================
5 ----
6 git-submodule - Initialize, update or inspect submodules
10 --------
11 [verse]
12 'git submodule' [--quiet] add [-b branch] [--] <repository> <path>
13 'git submodule' [--quiet] status [--cached] [--] [<path>...]
14 'git submodule' [--quiet] init [--] [<path>...]
15 'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase] [--] [<path>...]
16 'git submodule' [--quiet] summary [--summary-limit <n>] [commit] [--] [<path>...]
17 'git submodule' [--quiet] foreach <command>
18 'git submodule' [--quiet] sync [--] [<path>...]
22 -----------
23 Submodules allow foreign repositories to be embedded within
24 a dedicated subdirectory of the source tree, always pointed
25 at a particular commit.
27 They are not to be confused with remotes, which are meant mainly
28 for branches of the same project; submodules are meant for
29 different projects you would like to make part of your source tree,
30 while the history of the two projects still stays completely
31 independent and you cannot modify the contents of the submodule
32 from within the main project.
33 If you want to merge the project histories and want to treat the
34 aggregated whole as a single project from then on, you may want to
35 add a remote for the other project and use the 'subtree' merge strategy,
36 instead of treating the other project as a submodule. Directories
37 that come from both projects can be cloned and checked out as a whole
38 if you choose to go that route.
40 Submodules are composed from a so-called `gitlink` tree entry
41 in the main repository that refers to a particular commit object
42 within the inner repository that is completely separate.
43 A record in the `.gitmodules` file at the root of the source
44 tree assigns a logical name to the submodule and describes
45 the default URL the submodule shall be cloned from.
46 The logical name can be used for overriding this URL within your
47 local repository configuration (see 'submodule init').
49 This command will manage the tree entries and contents of the
50 gitmodules file for you, as well as inspect the status of your
51 submodules and update them.
52 When adding a new submodule to the tree, the 'add' subcommand
53 is to be used. However, when pulling a tree containing submodules,
54 these will not be checked out by default;
55 the 'init' and 'update' subcommands will maintain submodules
56 checked out and at appropriate revision in your working tree.
57 You can briefly inspect the up-to-date status of your submodules
58 using the 'status' subcommand and get a detailed overview of the
59 difference between the index and checkouts using the 'summary'
60 subcommand.
64 --------
65 add::
66 Add the given repository as a submodule at the given path
67 to the changeset to be committed next to the current
68 project: the current project is termed the "superproject".
69 +
70 This requires two arguments: <repository> and <path>.
71 +
72 <repository> is the URL of the new submodule's origin repository.
73 This may be either an absolute URL, or (if it begins with ./
74 or ../), the location relative to the superproject's origin
75 repository.
76 +
77 <path> is the relative location for the cloned submodule to
78 exist in the superproject. If <path> does not exist, then the
79 submodule is created by cloning from the named URL. If <path> does
80 exist and is already a valid git repository, then this is added
81 to the changeset without cloning. This second form is provided
82 to ease creating a new submodule from scratch, and presumes
83 the user will later push the submodule to the given URL.
84 +
85 In either case, the given URL is recorded into .gitmodules for
86 use by subsequent users cloning the superproject. If the URL is
87 given relative to the superproject's repository, the presumption
88 is the superproject and submodule repositories will be kept
89 together in the same relative location, and only the
90 superproject's URL needs to be provided: git-submodule will correctly
91 locate the submodule using the relative URL in .gitmodules.
93 status::
94 Show the status of the submodules. This will print the SHA-1 of the
95 currently checked out commit for each submodule, along with the
96 submodule path and the output of 'git-describe' for the
97 SHA-1. Each SHA-1 will be prefixed with `-` if the submodule is not
98 initialized and `+` if the currently checked out submodule commit
99 does not match the SHA-1 found in the index of the containing
100 repository. This command is the default command for 'git-submodule'.
102 init::
103 Initialize the submodules, i.e. register each submodule name
104 and url found in .gitmodules into .git/config.
105 The key used in .git/config is `submodule.$name.url`.
106 This command does not alter existing information in .git/config.
107 You can then customize the submodule clone URLs in .git/config
108 for your local setup and proceed to 'git submodule update';
109 you can also just use 'git submodule update --init' without
110 the explicit 'init' step if you do not intend to customize
111 any submodule locations.
113 update::
114 Update the registered submodules, i.e. clone missing submodules and
115 checkout the commit specified in the index of the containing repository.
116 This will make the submodules HEAD be detached unless '--rebase' or
117 '--merge' is specified or the key `submodule.$name.update` is set to
118 `rebase` or `merge`.
119 +
120 If the submodule is not yet initialized, and you just want to use the
121 setting as stored in .gitmodules, you can automatically initialize the
122 submodule with the --init option.
124 summary::
125 Show commit summary between the given commit (defaults to HEAD) and
126 working tree/index. For a submodule in question, a series of commits
127 in the submodule between the given super project commit and the
128 index or working tree (switched by --cached) are shown.
130 foreach::
131 Evaluates an arbitrary shell command in each checked out submodule.
132 The command has access to the variables $path and $sha1:
133 $path is the name of the submodule directory relative to the
134 superproject, and $sha1 is the commit as recorded in the superproject.
135 Any submodules defined in the superproject but not checked out are
136 ignored by this command. Unless given --quiet, foreach prints the name
137 of each submodule before evaluating the command.
138 A non-zero return from the command in any submodule causes
139 the processing to terminate. This can be overridden by adding '|| :'
140 to the end of the command.
141 +
142 As an example, "git submodule foreach 'echo $path `git rev-parse HEAD`' will
143 show the path and currently checked out commit for each submodule.
145 sync::
146 Synchronizes submodules' remote URL configuration setting
147 to the value specified in .gitmodules. This is useful when
148 submodule URLs change upstream and you need to update your local
149 repositories accordingly.
150 +
151 "git submodule sync" synchronizes all submodules while
152 "git submodule sync -- A" synchronizes submodule "A" only.
155 -------
156 -q::
157 --quiet::
158 Only print error messages.
160 -b::
161 --branch::
162 Branch of repository to add as submodule.
164 --cached::
165 This option is only valid for status and summary commands. These
166 commands typically use the commit found in the submodule HEAD, but
167 with this option, the commit stored in the index is used instead.
169 -n::
170 --summary-limit::
171 This option is only valid for the summary command.
172 Limit the summary size (number of commits shown in total).
173 Giving 0 will disable the summary; a negative number means unlimited
174 (the default). This limit only applies to modified submodules. The
175 size is always limited to 1 for added/deleted/typechanged submodules.
177 -N::
178 --no-fetch::
179 This option is only valid for the update command.
180 Don't fetch new objects from the remote site.
182 --rebase::
183 This option is only valid for the update command.
184 Rebase the current branch onto the commit recorded in the
185 superproject. If this option is given, the submodule's HEAD will not
186 be detached. If a a merge failure prevents this process, you will have
187 to resolve these failures with linkgit:git-rebase[1].
188 If the key `submodule.$name.update` is set to `rebase`, this option is
189 implicit.
191 --merge::
192 This option is only valid for the update command.
193 Merge the commit recorded in the superproject into the current branch
194 of the submodule. If this option is given, the submodule's HEAD will
195 not be detached. If a merge failure prevents this process, you will
196 have to resolve the resulting conflicts within the submodule with the
197 usual conflict resolution tools.
198 If the key `submodule.$name.update` is set to `merge`, this option is
199 implicit.
201 <path>...::
202 Paths to submodule(s). When specified this will restrict the command
203 to only operate on the submodules found at the specified paths.
204 (This argument is required with add).
207 -----
208 When initializing submodules, a .gitmodules file in the top-level directory
209 of the containing repository is used to find the url of each submodule.
210 This file should be formatted in the same way as `$GIT_DIR/config`. The key
211 to each submodule url is "submodule.$name.url". See linkgit:gitmodules[5]
212 for details.
216 ------
217 Written by Lars Hjemli <>
219 GIT
220 ---
221 Part of the linkgit:git[1] suite