NAME
----
-git-subtree - add, merge, and split subprojects stored in subtrees
+git-subtree - Merge subtrees together and split repository into subtrees
SYNOPSIS
--------
[verse]
-'git subtree' add --prefix=<prefix> <commit>
-'git subtree' merge --prefix=<prefix> <commit>
-'git subtree' pull --prefix=<prefix> <repository> <refspec...>
-'git subtree' split --prefix=<prefix> <commit...>
-
+'git subtree' add -P <prefix> <commit>
+'git subtree' pull -P <prefix> <repository> <refspec...>
+'git subtree' push -P <prefix> <repository> <refspec...>
+'git subtree' merge -P <prefix> <commit>
+'git subtree' split -P <prefix> [OPTIONS] [<commit>]
+
DESCRIPTION
-----------
-git subtree allows you to include an subproject in your
-own repository as a subdirectory, optionally including the
-subproject's entire history. For example, you could
-include the source code for a library as a subdirectory of your
-application.
-
-You can also extract the entire history of a subdirectory from
-your project and make it into a standalone project. For
-example, if a library you made for one application ends up being
-useful elsewhere, you can extract its entire history and publish
-that as its own git repository, without accidentally
-intermingling the history of your application project.
+Subtrees allow subprojects to be included within a subdirectory
+of the main project, optionally including the subproject's
+entire history.
+
+For example, you could include the source code for a library
+as a subdirectory of your application.
+
+Subtrees are not to be confused with submodules, which are meant for
+the same task. Unlike submodules, subtrees do not need any special
+constructions (like .gitmodule files or gitlinks) be present in
+your repository, and do not force end-users of your
+repository to do anything special or to understand how subtrees
+work. A subtree is just a subdirectory that can be
+committed to, branched, and merged along with your project in
+any way you want.
-Most importantly, you can alternate back and forth between these
-two operations. If the standalone library gets updated, you can
+They are also not to be confused with using the subtree merge
+strategy. The main difference is that, besides merging
+the other project as a subdirectory, you can also extract the
+entire history of a subdirectory from your project and make it
+into a standalone project. Unlike the subtree merge strategy
+you can alternate back and forth between these
+two operations. If the standalone library gets updated, you can
automatically merge the changes into your project; if you
update the library inside your project, you can "split" the
changes back out again and merge them back into the library
project.
-Unlike the 'git submodule' command, git subtree doesn't produce
-any special constructions (like .gitmodule files or gitlinks) in
-your repository, and doesn't require end-users of your
-repository to do anything special or to understand how subtrees
-work. A subtree is just another subdirectory and can be
-committed to, branched, and merged along with your project in
-any way you want.
+For example, if a library you made for one application ends up being
+useful elsewhere, you can extract its entire history and publish
+that as its own git repository, without accidentally
+intermingling the history of your application project.
+[TIP]
In order to keep your commit messages clean, we recommend that
people split their commits between the subtrees and the main
project as much as possible. That is, if you make a change that
--------
add::
Create the <prefix> subtree by importing its contents
- from the given commit. A new commit is created
- automatically, joining the imported project's history
- with your own. With '--squash', imports only a single
- commit from the subproject, rather than its entire
- history.
+ from the given <refspec> or <repository> and remote <refspec>.
+ A new commit is created automatically, joining the imported
+ project's history with your own. With '--squash', imports
+ only a single commit from the subproject, rather than its
+ entire history.
merge::
Merge recent changes up to <commit> into the <prefix>
Exactly like 'merge', but parallels 'git pull' in that
it fetches the given commit from the specified remote
repository.
+
+push::
+ Does a 'split' (see above) using the <prefix> supplied
+ and then does a 'git push' to push the result to the
+ repository and refspec. This can be used to push your
+ subtree to different branches of the remote repository.
split::
Extract a new, synthetic project history from the
--debug::
Produce even more unnecessary output messages on stderr.
+-P <prefix>::
--prefix=<prefix>::
Specify the path in the repository to the subtree you
- want to manipulate. This option is currently mandatory
+ want to manipulate. This option is mandatory
for all commands.
+-m <message>::
+--message=<message>::
+ This option is only valid for add, merge and pull (unsure).
+ Specify <message> as the commit message for the merge commit.
-OPTIONS FOR add, merge, AND pull
---------------------------------
+
+OPTIONS FOR add, merge, push, pull
+----------------------------------
--squash::
+ This option is only valid for add, merge, push and pull
+ commands.
+
Instead of merging the entire history from the subtree
project, produce only a single commit that contains all
the differences you want to merge, and then merge that
new commit into your project.
-
+
Using this option helps to reduce log clutter. People
rarely want to see every change that happened between
v1.0 and v1.1 of the library they're using, since none of the
OPTIONS FOR split
-----------------
--annotate=<annotation>::
+ This option is only valid for the split command.
+
When generating synthetic history, add <annotation> as a
prefix to each commit message. Since we're creating new
commits with the same commit message, but possibly
-b <branch>::
--branch=<branch>::
+ This option is only valid for the split command.
+
After generating the synthetic history, create a new
branch called <branch> that contains the new history.
This is suitable for immediate pushing upstream.
<branch> must not already exist.
--ignore-joins::
+ This option is only valid for the split command.
+
If you use '--rejoin', git subtree attempts to optimize
its history reconstruction to generate only the new
commits since the last '--rejoin'. '--ignore-join'
long time.
--onto=<onto>::
+ This option is only valid for the split command.
+
If your subtree was originally imported using something
other than git subtree, its history may not match what
git subtree is expecting. In that case, you can specify
this option.
--rejoin::
+ This option is only valid for the split command.
+
After splitting, merge the newly created synthetic
history back into your main project. That way, future
splits can search only the part of history that has
subproject's history to be part of your project anyway.
-EXAMPLE 1
----------
+EXAMPLE 1. Add command
+----------------------
Let's assume that you have a local repository that you would like
to add an external vendor library to. In this case we will add the
git-subtree repository as a subdirectory of your already existing
-git-extensions repository in ~/git-extensions/.
+git-extensions repository in ~/git-extensions/:
-First we need to fetch the remote objects
- $ cd ~/git-extensions
- $ git fetch git://github.com/apenwarr/git-subtree.git master
+ $ git subtree add --prefix=git-subtree --squash \
+ git://github.com/apenwarr/git-subtree.git master
'master' needs to be a valid remote ref and can be a different branch
name
-Now we add the vendor library with
- $ git subtree add --prefix=git-subtree --squash FETCH_HEAD
-
You can omit the --squash flag, but doing so will increase the number
of commits that are incldued in your local repository.
from the master branch of git://github.com/apenwarr/git-subtree.git
in our git-extensions repository.
-EXAMPLE 2
----------
+EXAMPLE 2. Extract a subtree using commit, merge and pull
+---------------------------------------------------------
Let's use the repository for the git source code as an example.
First, get your own copy of the git.git repository:
git log gitweb-latest..$(git subtree split --prefix=gitweb)
-EXAMPLE 3
----------
+EXAMPLE 3. Extract a subtree using branch
+-----------------------------------------
Suppose you have a source directory with many files and
subdirectories, and you want to extract the lib directory to its own
git project. Here's a short way to do it:
First, make the new repository wherever you want:
- <go to the new location>
- git init --bare
+
+ $ <go to the new location>
+ $ git init --bare
Back in your original directory:
- git subtree split --prefix=lib --annotate="(split)" -b split
+
+ $ git subtree split --prefix=lib --annotate="(split)" -b split
Then push the new branch onto the new empty repository:
- git push <new-repo> split:master
+ $ git push <new-repo> split:master
AUTHOR