Merge branch 'ph/submodule-rebase' (early part)
[git/git.git] / Documentation / git-submodule.txt
1 git-submodule(1)
2 ================
3
4 NAME
5 ----
6 git-submodule - Initialize, update or inspect submodules
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git submodule' [--quiet] add [-b branch]
13 [--reference <repository>] [--] <repository> <path>
14 'git submodule' [--quiet] status [--cached] [--] [<path>...]
15 'git submodule' [--quiet] init [--] [<path>...]
16 'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase]
17 [--reference <repository>] [--] [<path>...]
18 'git submodule' [--quiet] summary [--summary-limit <n>] [commit] [--] [<path>...]
19 'git submodule' [--quiet] foreach <command>
20 'git submodule' [--quiet] sync [--] [<path>...]
21
22
23 DESCRIPTION
24 -----------
25 Submodules allow foreign repositories to be embedded within
26 a dedicated subdirectory of the source tree, always pointed
27 at a particular commit.
28
29 They are not to be confused with remotes, which are meant mainly
30 for branches of the same project; submodules are meant for
31 different projects you would like to make part of your source tree,
32 while the history of the two projects still stays completely
33 independent and you cannot modify the contents of the submodule
34 from within the main project.
35 If you want to merge the project histories and want to treat the
36 aggregated whole as a single project from then on, you may want to
37 add a remote for the other project and use the 'subtree' merge strategy,
38 instead of treating the other project as a submodule. Directories
39 that come from both projects can be cloned and checked out as a whole
40 if you choose to go that route.
41
42 Submodules are composed from a so-called `gitlink` tree entry
43 in the main repository that refers to a particular commit object
44 within the inner repository that is completely separate.
45 A record in the `.gitmodules` file at the root of the source
46 tree assigns a logical name to the submodule and describes
47 the default URL the submodule shall be cloned from.
48 The logical name can be used for overriding this URL within your
49 local repository configuration (see 'submodule init').
50
51 This command will manage the tree entries and contents of the
52 gitmodules file for you, as well as inspect the status of your
53 submodules and update them.
54 When adding a new submodule to the tree, the 'add' subcommand
55 is to be used. However, when pulling a tree containing submodules,
56 these will not be checked out by default;
57 the 'init' and 'update' subcommands will maintain submodules
58 checked out and at appropriate revision in your working tree.
59 You can briefly inspect the up-to-date status of your submodules
60 using the 'status' subcommand and get a detailed overview of the
61 difference between the index and checkouts using the 'summary'
62 subcommand.
63
64
65 COMMANDS
66 --------
67 add::
68 Add the given repository as a submodule at the given path
69 to the changeset to be committed next to the current
70 project: the current project is termed the "superproject".
71 +
72 This requires two arguments: <repository> and <path>.
73 +
74 <repository> is the URL of the new submodule's origin repository.
75 This may be either an absolute URL, or (if it begins with ./
76 or ../), the location relative to the superproject's origin
77 repository.
78 +
79 <path> is the relative location for the cloned submodule to
80 exist in the superproject. If <path> does not exist, then the
81 submodule is created by cloning from the named URL. If <path> does
82 exist and is already a valid git repository, then this is added
83 to the changeset without cloning. This second form is provided
84 to ease creating a new submodule from scratch, and presumes
85 the user will later push the submodule to the given URL.
86 +
87 In either case, the given URL is recorded into .gitmodules for
88 use by subsequent users cloning the superproject. If the URL is
89 given relative to the superproject's repository, the presumption
90 is the superproject and submodule repositories will be kept
91 together in the same relative location, and only the
92 superproject's URL needs to be provided: git-submodule will correctly
93 locate the submodule using the relative URL in .gitmodules.
94
95 status::
96 Show the status of the submodules. This will print the SHA-1 of the
97 currently checked out commit for each submodule, along with the
98 submodule path and the output of 'git-describe' for the
99 SHA-1. Each SHA-1 will be prefixed with `-` if the submodule is not
100 initialized and `+` if the currently checked out submodule commit
101 does not match the SHA-1 found in the index of the containing
102 repository. This command is the default command for 'git-submodule'.
103
104 init::
105 Initialize the submodules, i.e. register each submodule name
106 and url found in .gitmodules into .git/config.
107 The key used in .git/config is `submodule.$name.url`.
108 This command does not alter existing information in .git/config.
109 You can then customize the submodule clone URLs in .git/config
110 for your local setup and proceed to 'git submodule update';
111 you can also just use 'git submodule update --init' without
112 the explicit 'init' step if you do not intend to customize
113 any submodule locations.
114
115 update::
116 Update the registered submodules, i.e. clone missing submodules and
117 checkout the commit specified in the index of the containing repository.
118 This will make the submodules HEAD be detached unless '--rebase' is
119 specified or the key `submodule.$name.update` is set to `rebase`.
120 +
121 If the submodule is not yet initialized, and you just want to use the
122 setting as stored in .gitmodules, you can automatically initialize the
123 submodule with the --init option.
124
125 summary::
126 Show commit summary between the given commit (defaults to HEAD) and
127 working tree/index. For a submodule in question, a series of commits
128 in the submodule between the given super project commit and the
129 index or working tree (switched by --cached) are shown.
130
131 foreach::
132 Evaluates an arbitrary shell command in each checked out submodule.
133 The command has access to the variables $path and $sha1:
134 $path is the name of the submodule directory relative to the
135 superproject, and $sha1 is the commit as recorded in the superproject.
136 Any submodules defined in the superproject but not checked out are
137 ignored by this command. Unless given --quiet, foreach prints the name
138 of each submodule before evaluating the command.
139 A non-zero return from the command in any submodule causes
140 the processing to terminate. This can be overridden by adding '|| :'
141 to the end of the command.
142 +
143 As an example, "git submodule foreach 'echo $path `git rev-parse HEAD`' will
144 show the path and currently checked out commit for each submodule.
145
146 sync::
147 Synchronizes submodules' remote URL configuration setting
148 to the value specified in .gitmodules. This is useful when
149 submodule URLs change upstream and you need to update your local
150 repositories accordingly.
151 +
152 "git submodule sync" synchronizes all submodules while
153 "git submodule sync -- A" synchronizes submodule "A" only.
154
155 OPTIONS
156 -------
157 -q::
158 --quiet::
159 Only print error messages.
160
161 -b::
162 --branch::
163 Branch of repository to add as submodule.
164
165 --cached::
166 This option is only valid for status and summary commands. These
167 commands typically use the commit found in the submodule HEAD, but
168 with this option, the commit stored in the index is used instead.
169
170 -n::
171 --summary-limit::
172 This option is only valid for the summary command.
173 Limit the summary size (number of commits shown in total).
174 Giving 0 will disable the summary; a negative number means unlimited
175 (the default). This limit only applies to modified submodules. The
176 size is always limited to 1 for added/deleted/typechanged submodules.
177
178 -N::
179 --no-fetch::
180 This option is only valid for the update command.
181 Don't fetch new objects from the remote site.
182
183 --rebase::
184 This option is only valid for the update command.
185 Rebase the current branch onto the commit recorded in the
186 superproject. If this option is given, the submodule's HEAD will not
187 be detached. If a a merge failure prevents this process, you will have
188 to resolve these failures with linkgit:git-rebase[1].
189 If the key `submodule.$name.update` is set to `rebase`, this option is
190 implicit.
191
192 --reference <repository>::
193 This option is only valid for add and update commands. These
194 commands sometimes need to clone a remote repository. In this case,
195 this option will be passed to the linkgit:git-clone[1] command.
196 +
197 *NOTE*: Do *not* use this option unless you have read the note
198 for linkgit:git-clone[1]'s --reference and --shared options carefully.
199
200 <path>...::
201 Paths to submodule(s). When specified this will restrict the command
202 to only operate on the submodules found at the specified paths.
203 (This argument is required with add).
204
205 FILES
206 -----
207 When initializing submodules, a .gitmodules file in the top-level directory
208 of the containing repository is used to find the url of each submodule.
209 This file should be formatted in the same way as `$GIT_DIR/config`. The key
210 to each submodule url is "submodule.$name.url". See linkgit:gitmodules[5]
211 for details.
212
213
214 AUTHOR
215 ------
216 Written by Lars Hjemli <hjemli@gmail.com>
217
218 GIT
219 ---
220 Part of the linkgit:git[1] suite