--- /dev/null
+++ b/contrib/subtree/git-subtree.html
@@ -0,0 +1,1235 @@
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+/* Author: Mihai Bazon, September 2002
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+}
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+/*]]>*/
+</script>
+</head>
+<body class="manpage">
+<div id="header">
+<h1>
+git-subtree(1) Manual Page
+</h1>
+<h2>NAME</h2>
+<div class="sectionbody">
+<p>git-subtree -
+   Merge subtrees together and split repository into subtrees
+</p>
+</div>
+</div>
+<div id="content">
+<div class="sect1">
+<h2 id="_synopsis">SYNOPSIS</h2>
+<div class="sectionbody">
+<div class="verseblock">
+<pre class="content"><em>git subtree</em> [&lt;options&gt;] -P &lt;prefix&gt; [-S[&lt;keyid&gt;]] add &lt;local-commit&gt;
+<em>git subtree</em> [&lt;options&gt;] -P &lt;prefix&gt; [-S[&lt;keyid&gt;]] add &lt;repository&gt; &lt;remote-ref&gt;
+<em>git subtree</em> [&lt;options&gt;] -P &lt;prefix&gt; [-S[&lt;keyid&gt;]] merge &lt;local-commit&gt; [&lt;repository&gt;]
+<em>git subtree</em> [&lt;options&gt;] -P &lt;prefix&gt; [-S[&lt;keyid&gt;]] split [&lt;local-commit&gt;]</pre>
+<div class="attribution">
+</div></div>
+<div class="verseblock">
+<pre class="content"><em>git subtree</em> [&lt;options&gt;] -P &lt;prefix&gt; [-S[&lt;keyid&gt;]] pull &lt;repository&gt; &lt;remote-ref&gt;
+<em>git subtree</em> [&lt;options&gt;] -P &lt;prefix&gt; [-S[&lt;keyid&gt;]] push &lt;repository&gt; &lt;refspec&gt;</pre>
+<div class="attribution">
+</div></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_description">DESCRIPTION</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Subtrees allow subprojects to be included within a subdirectory
+of the main project, optionally including the subproject&#8217;s
+entire history.</p></div>
+<div class="paragraph"><p>For example, you could include the source code for a library
+as a subdirectory of your application.</p></div>
+<div class="paragraph"><p>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 <em>.gitmodules</em> 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.</p></div>
+<div class="paragraph"><p>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.</p></div>
+<div class="paragraph"><p>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.</p></div>
+<div class="admonitionblock">
+<table><tr>
+<td class="icon">
+<div class="title">Tip</div>
+</td>
+<td class="content">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
+affects both the library and the main application, commit it in
+two pieces.  That way, when you split the library commits out
+later, their descriptions will still make sense.  But if this
+isn&#8217;t important to you, it&#8217;s not <strong>necessary</strong>.  <em>git subtree</em> will
+simply leave out the non-library-related parts of the commit
+when it splits it out into the subproject later.</td>
+</tr></table>
+</div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_commands">COMMANDS</h2>
+<div class="sectionbody">
+<div class="dlist"><dl>
+<dt class="hdlist1">
+add &lt;local-commit&gt;
+</dt>
+<dt class="hdlist1">
+add &lt;repository&gt; &lt;remote-ref&gt;
+</dt>
+<dd>
+<p>
+        Create the &lt;prefix&gt; subtree by importing its contents
+        from the given &lt;local-commit&gt; or &lt;repository&gt; and &lt;remote-ref&gt;.
+        A new commit is created automatically, joining the imported
+        project&#8217;s history with your own.  With <em>--squash</em>, import
+        only a single commit from the subproject, rather than its
+        entire history.
+</p>
+</dd>
+<dt class="hdlist1">
+merge &lt;local-commit&gt; [&lt;repository&gt;]
+</dt>
+<dd>
+<p>
+        Merge recent changes up to &lt;local-commit&gt; into the &lt;prefix&gt;
+        subtree.  As with normal <em>git merge</em>, this doesn&#8217;t
+        remove your own local changes; it just merges those
+        changes into the latest &lt;local-commit&gt;.  With <em>--squash</em>,
+        create only one commit that contains all the changes,
+        rather than merging in the entire history.
+</p>
+<div class="paragraph"><p>If you use <em>--squash</em>, the merge direction doesn&#8217;t always have to be
+forward; you can use this command to go back in time from v2.5 to v2.4,
+for example.  If your merge introduces a conflict, you can resolve it in
+the usual ways.</p></div>
+<div class="paragraph"><p>When using <em>--squash</em>, and the previous merge with <em>--squash</em> merged an
+annotated tag of the subtree repository, that tag needs to be available locally.
+If &lt;repository&gt; is given, a missing tag will automatically be fetched from that
+repository.</p></div>
+</dd>
+<dt class="hdlist1">
+split [&lt;local-commit&gt;] [&lt;repository&gt;]
+</dt>
+<dd>
+<p>
+        Extract a new, synthetic project history from the
+        history of the &lt;prefix&gt; subtree of &lt;local-commit&gt;, or of
+        HEAD if no &lt;local-commit&gt; is given.  The new history
+        includes only the commits (including merges) that
+        affected &lt;prefix&gt;, and each of those commits now has the
+        contents of &lt;prefix&gt; at the root of the project instead
+        of in a subdirectory.  Thus, the newly created history
+        is suitable for export as a separate git repository.
+</p>
+<div class="paragraph"><p>After splitting successfully, a single commit ID is printed to stdout.
+This corresponds to the HEAD of the newly created tree, which you can
+manipulate however you want.</p></div>
+<div class="paragraph"><p>Repeated splits of exactly the same history are guaranteed to be
+identical (i.e. to produce the same commit IDs) as long as the
+settings passed to <em>split</em> (such as <em>--annotate</em>) are the same.
+Because of this, if you add new commits and then re-split, the new
+commits will be attached as commits on top of the history you
+generated last time, so <em>git merge</em> and friends will work as expected.</p></div>
+<div class="paragraph"><p>When a previous merge with <em>--squash</em> merged an annotated tag of the
+subtree repository, that tag needs to be available locally.
+If &lt;repository&gt; is given, a missing tag will automatically be fetched from that
+repository.</p></div>
+</dd>
+<dt class="hdlist1">
+pull &lt;repository&gt; &lt;remote-ref&gt;
+</dt>
+<dd>
+<p>
+        Exactly like <em>merge</em>, but parallels <em>git pull</em> in that
+        it fetches the given ref from the specified remote
+        repository.
+</p>
+</dd>
+<dt class="hdlist1">
+push &lt;repository&gt; [+][&lt;local-commit&gt;:]&lt;remote-ref&gt;
+</dt>
+<dd>
+<p>
+        Does a <em>split</em> using the &lt;prefix&gt; subtree of &lt;local-commit&gt;
+        and then does a <em>git push</em> to push the result to the
+        &lt;repository&gt; and &lt;remote-ref&gt;.  This can be used to push your
+        subtree to different branches of the remote repository.  Just
+        as with <em>split</em>, if no &lt;local-commit&gt; is given, then HEAD is
+        used.  The optional leading <em>+</em> is ignored.
+</p>
+</dd>
+</dl></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_options_for_all_commands">OPTIONS FOR ALL COMMANDS</h2>
+<div class="sectionbody">
+<div class="dlist"><dl>
+<dt class="hdlist1">
+-q
+</dt>
+<dt class="hdlist1">
+--quiet
+</dt>
+<dd>
+<p>
+        Suppress unnecessary output messages on stderr.
+</p>
+</dd>
+<dt class="hdlist1">
+-d
+</dt>
+<dt class="hdlist1">
+--debug
+</dt>
+<dd>
+<p>
+        Produce even more unnecessary output messages on stderr.
+</p>
+</dd>
+<dt class="hdlist1">
+-P &lt;prefix&gt;
+</dt>
+<dt class="hdlist1">
+--prefix=&lt;prefix&gt;
+</dt>
+<dd>
+<p>
+        Specify the path in the repository to the subtree you
+        want to manipulate.  This option is mandatory
+        for all commands.
+</p>
+</dd>
+<dt class="hdlist1">
+-S[&lt;keyid&gt;]
+</dt>
+<dt class="hdlist1">
+--gpg-sign[=&lt;keyid&gt;]
+</dt>
+<dt class="hdlist1">
+--no-gpg-sign
+</dt>
+<dd>
+<p>
+        GPG-sign commits. The <code>keyid</code> argument is optional and
+        defaults to the committer identity; <code>--no-gpg-sign</code> is useful to
+        countermand a <code>--gpg-sign</code> option given earlier on the command line.
+</p>
+</dd>
+</dl></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_options_for_em_add_em_and_em_merge_em_also_em_pull_em_em_split_rejoin_em_and_em_push_rejoin_em">OPTIONS FOR <em>add</em> AND <em>merge</em> (ALSO: <em>pull</em>, <em>split --rejoin</em>, AND <em>push --rejoin</em>)</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>These options for <em>add</em> and <em>merge</em> may also be given to <em>pull</em> (which
+wraps <em>merge</em>), <em>split --rejoin</em> (which wraps either <em>add</em> or <em>merge</em>
+as appropriate), and <em>push --rejoin</em> (which wraps <em>split --rejoin</em>).</p></div>
+<div class="dlist"><dl>
+<dt class="hdlist1">
+--squash
+</dt>
+<dd>
+<p>
+        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.
+</p>
+<div class="paragraph"><p>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&#8217;re
+using, since none of the interim versions were ever included in their
+application.</p></div>
+<div class="paragraph"><p>Using <em>--squash</em> also helps avoid problems when the same subproject is
+included multiple times in the same project, or is removed and then
+re-added.  In such a case, it doesn&#8217;t make sense to combine the
+histories anyway, since it&#8217;s unclear which part of the history belongs
+to which subtree.</p></div>
+<div class="paragraph"><p>Furthermore, with <em>--squash</em>, you can switch back and forth between
+different versions of a subtree, rather than strictly forward.  <em>git
+subtree merge --squash</em> always adjusts the subtree to match the exactly
+specified commit, even if getting to that commit would require undoing
+some changes that were added earlier.</p></div>
+<div class="paragraph"><p>Whether or not you use <em>--squash</em>, changes made in your local repository
+remain intact and can be later split and send upstream to the
+subproject.</p></div>
+</dd>
+<dt class="hdlist1">
+-m &lt;message&gt;
+</dt>
+<dt class="hdlist1">
+--message=&lt;message&gt;
+</dt>
+<dd>
+<p>
+        Specify &lt;message&gt; as the commit message for the merge commit.
+</p>
+</dd>
+</dl></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_options_for_em_split_em_also_em_push_em">OPTIONS FOR <em>split</em> (ALSO: <em>push</em>)</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>These options for <em>split</em> may also be given to <em>push</em> (which wraps
+<em>split</em>).</p></div>
+<div class="dlist"><dl>
+<dt class="hdlist1">
+--annotate=&lt;annotation&gt;
+</dt>
+<dd>
+<p>
+        When generating synthetic history, add &lt;annotation&gt; as a prefix to each
+        commit message.  Since we&#8217;re creating new commits with the same commit
+        message, but possibly different content, from the original commits, this
+        can help to differentiate them and avoid confusion.
+</p>
+<div class="paragraph"><p>Whenever you split, you need to use the same &lt;annotation&gt;, or else you
+don&#8217;t have a guarantee that the new re-created history will be identical
+to the old one.  That will prevent merging from working correctly.  git
+subtree tries to make it work anyway, particularly if you use <em>--rejoin</em>,
+but it may not always be effective.</p></div>
+</dd>
+<dt class="hdlist1">
+-b &lt;branch&gt;
+</dt>
+<dt class="hdlist1">
+--branch=&lt;branch&gt;
+</dt>
+<dd>
+<p>
+        After generating the synthetic history, create a new branch called
+        &lt;branch&gt; that contains the new history.  This is suitable for immediate
+        pushing upstream.  &lt;branch&gt; must not already exist.
+</p>
+</dd>
+<dt class="hdlist1">
+--ignore-joins
+</dt>
+<dd>
+<p>
+        If you use <em>--rejoin</em>, git subtree attempts to optimize its history
+        reconstruction to generate only the new commits since the last
+        <em>--rejoin</em>.  <em>--ignore-joins</em> disables this behavior, forcing it to
+        regenerate the entire history.  In a large project, this can take a long
+        time.
+</p>
+</dd>
+<dt class="hdlist1">
+--onto=&lt;onto&gt;
+</dt>
+<dd>
+<p>
+        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 the commit ID &lt;onto&gt; that corresponds to the
+        first revision of the subproject&#8217;s history that was imported into your
+        project, and git subtree will attempt to build its history from there.
+</p>
+<div class="paragraph"><p>If you used <em>git subtree add</em>, you should never need this option.</p></div>
+</dd>
+<dt class="hdlist1">
+--rejoin
+</dt>
+<dd>
+<p>
+        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 been added since the most recent <em>--rejoin</em>.
+</p>
+<div class="paragraph"><p>If your split commits end up merged into the upstream subproject, and
+then you want to get the latest upstream version, this will allow git&#8217;s
+merge algorithm to more intelligently avoid conflicts (since it knows
+these synthetic commits are already part of the upstream repository).</p></div>
+<div class="paragraph"><p>Unfortunately, using this option results in <em>git log</em> showing an extra
+copy of every new commit that was created (the original, and the
+synthetic one).</p></div>
+<div class="paragraph"><p>If you do all your merges with <em>--squash</em>, make sure you also use
+<em>--squash</em> when you <em>split --rejoin</em>.</p></div>
+</dd>
+</dl></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_example_1_em_add_em_command">EXAMPLE 1. <em>add</em> command</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Let&#8217;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/:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree add --prefix=git-subtree --squash \
+        git://github.com/apenwarr/git-subtree.git master</code></pre>
+</div></div>
+<div class="paragraph"><p><em>master</em> needs to be a valid remote ref and can be a different branch
+name</p></div>
+<div class="paragraph"><p>You can omit the <em>--squash</em> flag, but doing so will increase the number
+of commits that are included in your local repository.</p></div>
+<div class="paragraph"><p>We now have a ~/git-extensions/git-subtree directory containing code
+from the master branch of git://github.com/apenwarr/git-subtree.git
+in our git-extensions repository.</p></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_example_2_extract_a_subtree_using_em_commit_em_em_merge_em_and_em_pull_em">EXAMPLE 2. Extract a subtree using <em>commit</em>, <em>merge</em> and <em>pull</em></h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Let&#8217;s use the repository for the git source code as an example.
+First, get your own copy of the git.git repository:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git clone git://git.kernel.org/pub/scm/git/git.git test-git
+$ cd test-git</code></pre>
+</div></div>
+<div class="paragraph"><p>gitweb (commit 1130ef3) was merged into git as of commit
+0a8f4f0, after which it was no longer maintained separately.
+But imagine it had been maintained separately, and we wanted to
+extract git&#8217;s changes to gitweb since that time, to share with
+the upstream.  You could do this:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree split --prefix=gitweb --annotate='(split) ' \
+        0a8f4f0^.. --onto=1130ef3 --rejoin \
+        --branch gitweb-latest
+$ gitk gitweb-latest
+$ git push git@github.com:whatever/gitweb.git gitweb-latest:master</code></pre>
+</div></div>
+<div class="paragraph"><p>(We use <em>0a8f4f0^..</em> because that means "all the changes from
+0a8f4f0 to the current version, including 0a8f4f0 itself.")</p></div>
+<div class="paragraph"><p>If gitweb had originally been merged using <em>git subtree add</em> (or
+a previous split had already been done with <em>--rejoin</em> specified)
+then you can do all your splits without having to remember any
+weird commit IDs:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree split --prefix=gitweb --annotate='(split) ' --rejoin \
+        --branch gitweb-latest2</code></pre>
+</div></div>
+<div class="paragraph"><p>And you can merge changes back in from the upstream project just
+as easily:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree pull --prefix=gitweb \
+        git@github.com:whatever/gitweb.git master</code></pre>
+</div></div>
+<div class="paragraph"><p>Or, using <em>--squash</em>, you can actually rewind to an earlier
+version of gitweb:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree merge --prefix=gitweb --squash gitweb-latest~10</code></pre>
+</div></div>
+<div class="paragraph"><p>Then make some changes:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ date &gt;gitweb/myfile
+$ git add gitweb/myfile
+$ git commit -m 'created myfile'</code></pre>
+</div></div>
+<div class="paragraph"><p>And fast forward again:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree merge --prefix=gitweb --squash gitweb-latest</code></pre>
+</div></div>
+<div class="paragraph"><p>And notice that your change is still intact:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ ls -l gitweb/myfile</code></pre>
+</div></div>
+<div class="paragraph"><p>And you can split it out and look at your changes versus
+the standard gitweb:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>git log gitweb-latest..$(git subtree split --prefix=gitweb)</code></pre>
+</div></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_example_3_extract_a_subtree_using_a_branch">EXAMPLE 3. Extract a subtree using a branch</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Suppose you have a source directory with many files and
+subdirectories, and you want to extract the lib directory to its own
+git project. Here&#8217;s a short way to do it:</p></div>
+<div class="paragraph"><p>First, make the new repository wherever you want:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ &lt;go to the new location&gt;
+$ git init --bare</code></pre>
+</div></div>
+<div class="paragraph"><p>Back in your original directory:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git subtree split --prefix=lib --annotate="(split)" -b split</code></pre>
+</div></div>
+<div class="paragraph"><p>Then push the new branch onto the new empty repository:</p></div>
+<div class="literalblock">
+<div class="content">
+<pre><code>$ git push &lt;new-repo&gt; split:master</code></pre>
+</div></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_author">AUTHOR</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Written by Avery Pennarun &lt;<a href="mailto:apenwarr@gmail.com">apenwarr@gmail.com</a>&gt;</p></div>
+</div>
+</div>
+<div class="sect1">
+<h2 id="_git">GIT</h2>
+<div class="sectionbody">
+<div class="paragraph"><p>Part of the <a href="git.html">git(1)</a> suite</p></div>
+</div>
+</div>
+</div>
+<div id="footnotes"><hr /></div>
+<div id="footer">
+<div id="footer-text">
+Last updated
+ 2026-06-29 12:32:26 EDT
+</div>
+</div>
+</body>
+</html>
