diff --git a/Documentation/Makefile b/Documentation/Makefile
index 5314068d32f1e9205ec7b76c9356674a414d773c..5e012f48e360985f8433da971daa1de8075da758 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -17,7 +17,7 @@ ARTICLES += hooks
ARTICLES += everyday
ARTICLES += git-tools
# with their own formatting rules.
-SP_ARTICLES = glossary howto/revert-branch-rebase
+SP_ARTICLES = glossary howto/revert-branch-rebase user-manual
DOC_HTML += $(patsubst %,%.html,$(ARTICLES) $(SP_ARTICLES))
@@ -99,6 +99,12 @@ clean:
%.xml : %.txt
asciidoc -b docbook -d manpage -f asciidoc.conf $<
+user-manual.xml: user-manual.txt user-manual.conf
+ asciidoc -b docbook -d book $<
+
+user-manual.html: user-manual.xml
+ xmlto -m /etc/asciidoc/docbook-xsl/xhtml.xsl html-nochunks $<
+
glossary.html : glossary.txt sort_glossary.pl
cat $< | \
perl sort_glossary.pl | \
diff --git a/Documentation/docbook-xsl.css b/Documentation/docbook-xsl.css
new file mode 100644
index 0000000000000000000000000000000000000000..8821e305dd6d5df919e376d2d9c3d0d5716cc074
--- /dev/null
+++ b/Documentation/docbook-xsl.css
@@ -0,0 +1,286 @@
+/*
+ CSS stylesheet for XHTML produced by DocBook XSL stylesheets.
+ Tested with XSL stylesheets 1.61.2, 1.67.2
+*/
+
+span.strong {
+ font-weight: bold;
+}
+
+body blockquote {
+ margin-top: .75em;
+ line-height: 1.5;
+ margin-bottom: .75em;
+}
+
+html body {
+ margin: 1em 5% 1em 5%;
+ line-height: 1.2;
+}
+
+body div {
+ margin: 0;
+}
+
+h1, h2, h3, h4, h5, h6,
+div.toc p b,
+div.list-of-figures p b,
+div.list-of-tables p b,
+div.abstract p.title
+{
+ color: #527bbd;
+ font-family: tahoma, verdana, sans-serif;
+}
+
+div.toc p:first-child,
+div.list-of-figures p:first-child,
+div.list-of-tables p:first-child,
+div.example p.title
+{
+ margin-bottom: 0.2em;
+}
+
+body h1 {
+ margin: .0em 0 0 -4%;
+ line-height: 1.3;
+ border-bottom: 2px solid silver;
+}
+
+body h2 {
+ margin: 0.5em 0 0 -4%;
+ line-height: 1.3;
+ border-bottom: 2px solid silver;
+}
+
+body h3 {
+ margin: .8em 0 0 -3%;
+ line-height: 1.3;
+}
+
+body h4 {
+ margin: .8em 0 0 -3%;
+ line-height: 1.3;
+}
+
+body h5 {
+ margin: .8em 0 0 -2%;
+ line-height: 1.3;
+}
+
+body h6 {
+ margin: .8em 0 0 -1%;
+ line-height: 1.3;
+}
+
+body hr {
+ border: none; /* Broken on IE6 */
+}
+div.footnotes hr {
+ border: 1px solid silver;
+}
+
+div.navheader th, div.navheader td, div.navfooter td {
+ font-family: sans-serif;
+ font-size: 0.9em;
+ font-weight: bold;
+ color: #527bbd;
+}
+div.navheader img, div.navfooter img {
+ border-style: none;
+}
+div.navheader a, div.navfooter a {
+ font-weight: normal;
+}
+div.navfooter hr {
+ border: 1px solid silver;
+}
+
+body td {
+ line-height: 1.2
+}
+
+body th {
+ line-height: 1.2;
+}
+
+ol {
+ line-height: 1.2;
+}
+
+ul, body dir, body menu {
+ line-height: 1.2;
+}
+
+html {
+ margin: 0;
+ padding: 0;
+}
+
+body h1, body h2, body h3, body h4, body h5, body h6 {
+ margin-left: 0
+}
+
+body pre {
+ margin: 0.5em 10% 0.5em 1em;
+ line-height: 1.0;
+ color: navy;
+}
+
+tt.literal, code.literal {
+ color: navy;
+}
+
+div.literallayout p {
+ padding: 0em;
+ margin: 0em;
+}
+
+div.literallayout {
+ font-family: monospace;
+# margin: 0.5em 10% 0.5em 1em;
+ margin: 0em;
+ color: navy;
+ border: 1px solid silver;
+ background: #f4f4f4;
+ padding: 0.5em;
+}
+
+.programlisting, .screen {
+ border: 1px solid silver;
+ background: #f4f4f4;
+ margin: 0.5em 10% 0.5em 0;
+ padding: 0.5em 1em;
+}
+
+div.sidebar {
+ background: #ffffee;
+ margin: 1.0em 10% 0.5em 0;
+ padding: 0.5em 1em;
+ border: 1px solid silver;
+}
+div.sidebar * { padding: 0; }
+div.sidebar div { margin: 0; }
+div.sidebar p.title {
+ font-family: sans-serif;
+ margin-top: 0.5em;
+ margin-bottom: 0.2em;
+}
+
+div.bibliomixed {
+ margin: 0.5em 5% 0.5em 1em;
+}
+
+div.glossary dt {
+ font-weight: bold;
+}
+div.glossary dd p {
+ margin-top: 0.2em;
+}
+
+dl {
+ margin: .8em 0;
+ line-height: 1.2;
+}
+
+dt {
+ margin-top: 0.5em;
+}
+
+dt span.term {
+ font-style: italic;
+}
+
+div.variablelist dd p {
+ margin-top: 0;
+}
+
+div.itemizedlist li, div.orderedlist li {
+ margin-left: -0.8em;
+ margin-top: 0.5em;
+}
+
+ul, ol {
+ list-style-position: outside;
+}
+
+div.sidebar ul, div.sidebar ol {
+ margin-left: 2.8em;
+}
+
+div.itemizedlist p.title,
+div.orderedlist p.title,
+div.variablelist p.title
+{
+ margin-bottom: -0.8em;
+}
+
+div.revhistory table {
+ border-collapse: collapse;
+ border: none;
+}
+div.revhistory th {
+ border: none;
+ color: #527bbd;
+ font-family: tahoma, verdana, sans-serif;
+}
+div.revhistory td {
+ border: 1px solid silver;
+}
+
+/* Keep TOC and index lines close together. */
+div.toc dl, div.toc dt,
+div.list-of-figures dl, div.list-of-figures dt,
+div.list-of-tables dl, div.list-of-tables dt,
+div.indexdiv dl, div.indexdiv dt
+{
+ line-height: normal;
+ margin-top: 0;
+ margin-bottom: 0;
+}
+
+/*
+ Table styling does not work because of overriding attributes in
+ generated HTML.
+*/
+div.table table,
+div.informaltable table
+{
+ margin-left: 0;
+ margin-right: 5%;
+ margin-bottom: 0.8em;
+}
+div.informaltable table
+{
+ margin-top: 0.4em
+}
+div.table thead,
+div.table tfoot,
+div.table tbody,
+div.informaltable thead,
+div.informaltable tfoot,
+div.informaltable tbody
+{
+ /* No effect in IE6. */
+ border-top: 2px solid #527bbd;
+ border-bottom: 2px solid #527bbd;
+}
+div.table thead, div.table tfoot,
+div.informaltable thead, div.informaltable tfoot
+{
+ font-weight: bold;
+}
+
+div.mediaobject img {
+ border: 1px solid silver;
+ margin-bottom: 0.8em;
+}
+div.figure p.title,
+div.table p.title
+{
+ margin-top: 1em;
+ margin-bottom: 0.4em;
+}
+
+@media print {
+ div.navheader, div.navfooter { display: none; }
+}
diff --git a/Documentation/user-manual.conf b/Documentation/user-manual.conf
new file mode 100644
index 0000000000000000000000000000000000000000..92b01ecf715f216bf79e3f775813d1df66000c7e
--- /dev/null
+++ b/Documentation/user-manual.conf
@@ -0,0 +1,21 @@
+[titles]
+ underlines="__","==","--","~~","^^"
+
+[attributes]
+caret=^
+startsb=[
+endsb=]
+tilde=~
+
+[gitlink-inlinemacro]
+{target}{0?({0})}
+
+ifdef::backend-docbook[]
+# "unbreak" docbook-xsl v1.68 for manpages. v1.69 works with or without this.
+[listingblock]
+{title}
+
+|
+
+{title#}
+endif::backend-docbook[]
diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
new file mode 100644
index 0000000000000000000000000000000000000000..b6916d11b228b3277eaa359573eedd9df0add6e8
--- /dev/null
+++ b/Documentation/user-manual.txt
@@ -0,0 +1,2959 @@
+Git User's Manual
+_________________
+
+This manual is designed to be readable by someone with basic unix
+commandline skills, but no previous knowledge of git.
+
+Chapter 1 gives a brief overview of git commands, without any
+explanation; you may prefer to skip to chapter 2 on a first reading.
+
+Chapters 2 and 3 explain how to fetch and study a project using
+git--the tools you'd need to build and test a particular version of a
+software project, to search for regressions, and so on.
+
+Chapter 4 explains how to do development with git, and chapter 5 how
+to share that development with others.
+
+Further chapters cover more specialized topics.
+
+Comprehensive reference documentation is available through the man
+pages. For a command such as "git clone", just use
+
+------------------------------------------------
+$ man git-clone
+------------------------------------------------
+
+Git Quick Start
+===============
+
+This is a quick summary of the major commands; the following chapters
+will explain how these work in more detail.
+
+Creating a new repository
+-------------------------
+
+From a tarball:
+
+-----------------------------------------------
+$ tar xzf project.tar.gz
+$ cd project
+$ git init
+Initialized empty Git repository in .git/
+$ git add .
+$ git commit
+-----------------------------------------------
+
+From a remote repository:
+
+-----------------------------------------------
+$ git clone git://example.com/pub/project.git
+$ cd project
+-----------------------------------------------
+
+Managing branches
+-----------------
+
+-----------------------------------------------
+$ git branch # list all branches in this repo
+$ git checkout test # switch working directory to branch "test"
+$ git branch new # create branch "new" starting at current HEAD
+$ git branch -d new # delete branch "new"
+-----------------------------------------------
+
+Instead of basing new branch on current HEAD (the default), use:
+
+-----------------------------------------------
+$ git branch new test # branch named "test"
+$ git branch new v2.6.15 # tag named v2.6.15
+$ git branch new HEAD^ # commit before the most recent
+$ git branch new HEAD^^ # commit before that
+$ git branch new test~10 # ten commits before tip of branch "test"
+-----------------------------------------------
+
+Create and switch to a new branch at the same time:
+
+-----------------------------------------------
+$ git checkout -b new v2.6.15
+-----------------------------------------------
+
+Update and examine branches from the repository you cloned from:
+
+-----------------------------------------------
+$ git fetch # update
+$ git branch -r # list
+ origin/master
+ origin/next
+ ...
+$ git branch checkout -b masterwork origin/master
+-----------------------------------------------
+
+Fetch a branch from a different repository, and give it a new
+name in your repository:
+
+-----------------------------------------------
+$ git fetch git://example.com/project.git theirbranch:mybranch
+$ git fetch git://example.com/project.git v2.6.15:mybranch
+-----------------------------------------------
+
+Keep a list of repositories you work with regularly:
+
+-----------------------------------------------
+$ git remote add example git://example.com/project.git
+$ git remote # list remote repositories
+example
+origin
+$ git remote show example # get details
+* remote example
+ URL: git://example.com/project.git
+ Tracked remote branches
+ master next ...
+$ git fetch example # update branches from example
+$ git branch -r # list all remote branches
+-----------------------------------------------
+
+
+Exploring history
+-----------------
+
+-----------------------------------------------
+$ gitk # visualize and browse history
+$ git log # list all commits
+$ git log src/ # ...modifying src/
+$ git log v2.6.15..v2.6.16 # ...in v2.6.16, not in v2.6.15
+$ git log master..test # ...in branch test, not in branch master
+$ git log test..master # ...in branch master, but not in test
+$ git log test...master # ...in one branch, not in both
+$ git log -S'foo()' # ...where difference contain "foo()"
+$ git log --since="2 weeks ago"
+$ git log -p # show patches as well
+$ git show # most recent commit
+$ git diff v2.6.15..v2.6.16 # diff between two tagged versions
+$ git diff v2.6.15..HEAD # diff with current head
+$ git grep "foo()" # search working directory for "foo()"
+$ git grep v2.6.15 "foo()" # search old tree for "foo()"
+$ git show v2.6.15:a.txt # look at old version of a.txt
+-----------------------------------------------
+
+Search for regressions:
+
+-----------------------------------------------
+$ git bisect start
+$ git bisect bad # current version is bad
+$ git bisect good v2.6.13-rc2 # last known good revision
+Bisecting: 675 revisions left to test after this
+ # test here, then:
+$ git bisect good # if this revision is good, or
+$ git bisect bad # if this revision is bad.
+ # repeat until done.
+-----------------------------------------------
+
+Making changes
+--------------
+
+Make sure git knows who to blame:
+
+------------------------------------------------
+$ cat >~/.gitconfig <<\EOF
+[user]
+name = Your Name Comes Here
+email = you@yourdomain.example.com
+EOF
+------------------------------------------------
+
+Select file contents to include in the next commit, then make the
+commit:
+
+-----------------------------------------------
+$ git add a.txt # updated file
+$ git add b.txt # new file
+$ git rm c.txt # old file
+$ git commit
+-----------------------------------------------
+
+Or, prepare and create the commit in one step:
+
+-----------------------------------------------
+$ git commit d.txt # use latest content only of d.txt
+$ git commit -a # use latest content of all tracked files
+-----------------------------------------------
+
+Merging
+-------
+
+-----------------------------------------------
+$ git merge test # merge branch "test" into the current branch
+$ git pull git://example.com/project.git master
+ # fetch and merge in remote branch
+$ git pull . test # equivalent to git merge test
+-----------------------------------------------
+
+Sharing your changes
+--------------------
+
+Importing or exporting patches:
+
+-----------------------------------------------
+$ git format-patch origin..HEAD # format a patch for each commit
+ # in HEAD but not in origin
+$ git-am mbox # import patches from the mailbox "mbox"
+-----------------------------------------------
+
+Fetch a branch in a different git repository, then merge into the
+current branch:
+
+-----------------------------------------------
+$ git pull git://example.com/project.git theirbranch
+-----------------------------------------------
+
+Store the fetched branch into a local branch before merging into the
+current branch:
+
+-----------------------------------------------
+$ git pull git://example.com/project.git theirbranch:mybranch
+-----------------------------------------------
+
+After creating commits on a local branch, update the remote
+branch with your commits:
+
+-----------------------------------------------
+$ git push ssh://example.com/project.git mybranch:theirbranch
+-----------------------------------------------
+
+When remote and local branch are both named "test":
+
+-----------------------------------------------
+$ git push ssh://example.com/project.git test
+-----------------------------------------------
+
+Shortcut version for a frequently used remote repository:
+
+-----------------------------------------------
+$ git remote add example ssh://example.com/project.git
+$ git push example test
+-----------------------------------------------
+
+Repository maintenance
+----------------------
+
+Check for corruption:
+
+-----------------------------------------------
+$ git fsck
+-----------------------------------------------
+
+Recompress, remove unused cruft:
+
+-----------------------------------------------
+$ git gc
+-----------------------------------------------
+
+Repositories and Branches
+=========================
+
+How to get a git repository
+---------------------------
+
+It will be useful to have a git repository to experiment with as you
+read this manual.
+
+The best way to get one is by using the gitlink:git-clone[1] command
+to download a copy of an existing repository for a project that you
+are interested in. If you don't already have a project in mind, here
+are some interesting examples:
+
+------------------------------------------------
+ # git itself (approx. 10MB download):
+$ git clone git://git.kernel.org/pub/scm/git/git.git
+ # the linux kernel (approx. 150MB download):
+$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
+------------------------------------------------
+
+The initial clone may be time-consuming for a large project, but you
+will only need to clone once.
+
+The clone command creates a new directory named after the project
+("git" or "linux-2.6" in the examples above). After you cd into this
+directory, you will see that it contains a copy of the project files,
+together with a special top-level directory named ".git", which
+contains all the information about the history of the project.
+
+In most of the following, examples will be taken from one of the two
+repositories above.
+
+How to check out a different version of a project
+-------------------------------------------------
+
+Git is best thought of as a tool for storing the history of a
+collection of files. It stores the history as a compressed
+collection of interrelated snapshots (versions) of the project's
+contents.
+
+A single git repository may contain multiple branches. Each branch
+is a bookmark referencing a particular point in the project history.
+The gitlink:git-branch[1] command shows you the list of branches:
+
+------------------------------------------------
+$ git branch
+* master
+------------------------------------------------
+
+A freshly cloned repository contains a single branch, named "master",
+and the working directory contains the version of the project
+referred to by the master branch.
+
+Most projects also use tags. Tags, like branches, are references
+into the project's history, and can be listed using the
+gitlink:git-tag[1] command:
+
+------------------------------------------------
+$ git tag -l
+v2.6.11
+v2.6.11-tree
+v2.6.12
+v2.6.12-rc2
+v2.6.12-rc3
+v2.6.12-rc4
+v2.6.12-rc5
+v2.6.12-rc6
+v2.6.13
+...
+------------------------------------------------
+
+Tags are expected to always point at the same version of a project,
+while branches are expected to advance as development progresses.
+
+Create a new branch pointing to one of these versions and check it
+out using gitlink:git-checkout[1]:
+
+------------------------------------------------
+$ git checkout -b new v2.6.13
+------------------------------------------------
+
+The working directory then reflects the contents that the project had
+when it was tagged v2.6.13, and gitlink:git-branch[1] shows two
+branches, with an asterisk marking the currently checked-out branch:
+
+------------------------------------------------
+$ git branch
+ master
+* new
+------------------------------------------------
+
+If you decide that you'd rather see version 2.6.17, you can modify
+the current branch to point at v2.6.17 instead, with
+
+------------------------------------------------
+$ git reset --hard v2.6.17
+------------------------------------------------
+
+Note that if the current branch was your only reference to a
+particular point in history, then resetting that branch may leave you
+with no way to find the history it used to point to; so use this
+command carefully.
+
+Understanding History: Commits
+------------------------------
+
+Every change in the history of a project is represented by a commit.
+The gitlink:git-show[1] command shows the most recent commit on the
+current branch:
+
+------------------------------------------------
+$ git show
+commit 2b5f6dcce5bf94b9b119e9ed8d537098ec61c3d2
+Author: Jamal Hadi Salim
+Date: Sat Dec 2 22:22:25 2006 -0800
+
+ [XFRM]: Fix aevent structuring to be more complete.
+
+ aevents can not uniquely identify an SA. We break the ABI with this
+ patch, but consensus is that since it is not yet utilized by any
+ (known) application then it is fine (better do it now than later).
+
+ Signed-off-by: Jamal Hadi Salim
+ Signed-off-by: David S. Miller
+
+diff --git a/Documentation/networking/xfrm_sync.txt b/Documentation/networking/xfrm_sync.txt
+index 8be626f..d7aac9d 100644
+--- a/Documentation/networking/xfrm_sync.txt
++++ b/Documentation/networking/xfrm_sync.txt
+@@ -47,10 +47,13 @@ aevent_id structure looks like:
+
+ struct xfrm_aevent_id {
+ struct xfrm_usersa_id sa_id;
++ xfrm_address_t saddr;
+ __u32 flags;
++ __u32 reqid;
+ };
+...
+------------------------------------------------
+
+As you can see, a commit shows who made the latest change, what they
+did, and why.
+
+Every commit has a 40-hexdigit id, sometimes called the "object name"
+or the "SHA1 id", shown on the first line of the "git show" output.
+You can usually refer to a commit by a shorter name, such as a tag or a
+branch name, but this longer name can also be useful. Most
+importantly, it is a globally unique name for this commit: so if you
+tell somebody else the object name (for example in email), then you are
+guaranteed that name will refer to the same commit in their repository
+that you it does in yours (assuming their repository has that commit at
+all).
+
+Understanding history: commits, parents, and reachability
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Every commit (except the very first commit in a project) also has a
+parent commit which shows what happened before this commit.
+Following the chain of parents will eventually take you back to the
+beginning of the project.
+
+However, the commits do not form a simple list; git allows lines of
+development to diverge and then reconverge, and the point where two
+lines of development reconverge is called a "merge". The commit
+representing a merge can therefore have more than one parent, with
+each parent representing the most recent commit on one of the lines
+of development leading to that point.
+
+The best way to see how this works is using the gitlink:gitk[1]
+command; running gitk now on a git repository and looking for merge
+commits will help understand how the git organizes history.
+
+In the following, we say that commit X is "reachable" from commit Y
+if commit X is an ancestor of commit Y. Equivalently, you could say
+that Y is a descendent of X, or that there is a chain of parents
+leading from commit Y to commit X.
+
+Undestanding history: History diagrams
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+We will sometimes represent git history using diagrams like the one
+below. Commits are shown as "o", and the links between them with
+lines drawn with - / and \. Time goes left to right:
+
+ o--o--o <-- Branch A
+ /
+ o--o--o <-- master
+ \
+ o--o--o <-- Branch B
+
+If we need to talk about a particular commit, the character "o" may
+be replaced with another letter or number.
+
+Understanding history: What is a branch?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Though we've been using the word "branch" to mean a kind of reference
+to a particular commit, the word branch is also commonly used to
+refer to the line of commits leading up to that point. In the
+example above, git may think of the branch named "A" as just a
+pointer to one particular commit, but we may refer informally to the
+line of three commits leading up to that point as all being part of
+"branch A".
+
+If we need to make it clear that we're just talking about the most
+recent commit on the branch, we may refer to that commit as the
+"head" of the branch.
+
+Manipulating branches
+---------------------
+
+Creating, deleting, and modifying branches is quick and easy; here's
+a summary of the commands:
+
+git branch::
+ list all branches
+git branch ::
+ create a new branch named , referencing the same
+ point in history as the current branch
+git branch ::
+ create a new branch named , referencing
+ , which may be specified any way you like,
+ including using a branch name or a tag name
+git branch -d ::
+ delete the branch ; if the branch you are deleting
+ points to a commit which is not reachable from this branch,
+ this command will fail with a warning.
+git branch -D ::
+ even if the branch points to a commit not reachable
+ from the current branch, you may know that that commit
+ is still reachable from some other branch or tag. In that
+ case it is safe to use this command to force git to delete
+ the branch.
+git checkout ::
+ make the current branch , updating the working
+ directory to reflect the version referenced by
+git checkout -b ::
+ create a new branch referencing , and
+ check it out.
+
+It is also useful to know that the special symbol "HEAD" can always
+be used to refer to the current branch.
+
+Examining branches from a remote repository
+-------------------------------------------
+
+The "master" branch that was created at the time you cloned is a copy
+of the HEAD in the repository that you cloned from. That repository
+may also have had other branches, though, and your local repository
+keeps branches which track each of those remote branches, which you
+can view using the "-r" option to gitlink:git-branch[1]:
+
+------------------------------------------------
+$ git branch -r
+ origin/HEAD
+ origin/html
+ origin/maint
+ origin/man
+ origin/master
+ origin/next
+ origin/pu
+ origin/todo
+------------------------------------------------
+
+You cannot check out these remote-tracking branches, but you can
+examine them on a branch of your own, just as you would a tag:
+
+------------------------------------------------
+$ git checkout -b my-todo-copy origin/todo
+------------------------------------------------
+
+Note that the name "origin" is just the name that git uses by default
+to refer to the repository that you cloned from.
+
+[[how-git-stores-references]]
+Naming branches, tags, and other references
+-------------------------------------------
+
+Branches, remote-tracking branches, and tags are all references to
+commits. All references are named with a slash-separated path name
+starting with "refs"; the names we've been using so far are actually
+shorthand:
+
+ - The branch "test" is short for "refs/heads/test".
+ - The tag "v2.6.18" is short for "refs/tags/v2.6.18".
+ - "origin/master" is short for "refs/remotes/origin/master".
+
+The full name is occasionally useful if, for example, there ever
+exists a tag and a branch with the same name.
+
+As another useful shortcut, if the repository "origin" posesses only
+a single branch, you can refer to that branch as just "origin".
+
+More generally, if you have defined a remote repository named
+"example", you can refer to the branch in that repository as
+"example". And for a repository with multiple branches, this will
+refer to the branch designated as the "HEAD" branch.
+
+For the complete list of paths which git checks for references, and
+the order it uses to decide which to choose when there are multiple
+references with the same shorthand name, see the "SPECIFYING
+REVISIONS" section of gitlink:git-rev-parse[1].
+
+[[Updating-a-repository-with-git-fetch]]
+Updating a repository with git fetch
+------------------------------------
+
+Eventually the developer cloned from will do additional work in her
+repository, creating new commits and advancing the branches to point
+at the new commits.
+
+The command "git fetch", with no arguments, will update all of the
+remote-tracking branches to the latest version found in her
+repository. It will not touch any of your own branches--not even the
+"master" branch that was created for you on clone.
+
+Fetching branches from other repositories
+-----------------------------------------
+
+You can also track branches from repositories other than the one you
+cloned from, using gitlink:git-remote[1]:
+
+-------------------------------------------------
+$ git remote add linux-nfs git://linux-nfs.org/pub/nfs-2.6.git
+$ git fetch
+* refs/remotes/linux-nfs/master: storing branch 'master' ...
+ commit: bf81b46
+-------------------------------------------------
+
+New remote-tracking branches will be stored under the shorthand name
+that you gave "git remote add", in this case linux-nfs:
+
+-------------------------------------------------
+$ git branch -r
+linux-nfs/master
+origin/master
+-------------------------------------------------
+
+If you run "git fetch " later, the tracking branches for the
+named will be updated.
+
+If you examine the file .git/config, you will see that git has added
+a new stanza:
+
+-------------------------------------------------
+$ cat .git/config
+...
+[remote "linux-nfs"]
+ url = git://linux-nfs.org/~bfields/git.git
+ fetch = +refs/heads/*:refs/remotes/linux-nfs-read/*
+...
+-------------------------------------------------
+
+This is what causes git to track the remote's branches; you may modify
+or delete these configuration options by editing .git/config with a
+text editor. (See the "CONFIGURATION FILE" section of
+gitlink:git-config[1] for details.)
+
+Exploring git history
+=====================
+
+Git is best thought of as a tool for storing the history of a
+collection of files. It does this by storing compressed snapshots of
+the contents of a file heirarchy, together with "commits" which show
+the relationships between these snapshots.
+
+Git provides extremely flexible and fast tools for exploring the
+history of a project.
+
+We start with one specialized tool which is useful for finding the
+commit that introduced a bug into a project.
+
+How to use bisect to find a regression
+--------------------------------------
+
+Suppose version 2.6.18 of your project worked, but the version at
+"master" crashes. Sometimes the best way to find the cause of such a
+regression is to perform a brute-force search through the project's
+history to find the particular commit that caused the problem. The
+gitlink:git-bisect[1] command can help you do this:
+
+-------------------------------------------------
+$ git bisect start
+$ git bisect good v2.6.18
+$ git bisect bad master
+Bisecting: 3537 revisions left to test after this
+[65934a9a028b88e83e2b0f8b36618fe503349f8e] BLOCK: Make USB storage depend on SCSI rather than selecting it [try #6]
+-------------------------------------------------
+
+If you run "git branch" at this point, you'll see that git has
+temporarily moved you to a new branch named "bisect". This branch
+points to a commit (with commit id 65934...) that is reachable from
+v2.6.19 but not from v2.6.18. Compile and test it, and see whether
+it crashes. Assume it does crash. Then:
+
+-------------------------------------------------
+$ git bisect bad
+Bisecting: 1769 revisions left to test after this
+[7eff82c8b1511017ae605f0c99ac275a7e21b867] i2c-core: Drop useless bitmaskings
+-------------------------------------------------
+
+checks out an older version. Continue like this, telling git at each
+stage whether the version it gives you is good or bad, and notice
+that the number of revisions left to test is cut approximately in
+half each time.
+
+After about 13 tests (in this case), it will output the commit id of
+the guilty commit. You can then examine the commit with
+gitlink:git-show[1], find out who wrote it, and mail them your bug
+report with the commit id. Finally, run
+
+-------------------------------------------------
+$ git bisect reset
+-------------------------------------------------
+
+to return you to the branch you were on before and delete the
+temporary "bisect" branch.
+
+Note that the version which git-bisect checks out for you at each
+point is just a suggestion, and you're free to try a different
+version if you think it would be a good idea. For example,
+occasionally you may land on a commit that broke something unrelated;
+run
+
+-------------------------------------------------
+$ git bisect-visualize
+-------------------------------------------------
+
+which will run gitk and label the commit it chose with a marker that
+says "bisect". Chose a safe-looking commit nearby, note its commit
+id, and check it out with:
+
+-------------------------------------------------
+$ git reset --hard fb47ddb2db...
+-------------------------------------------------
+
+then test, run "bisect good" or "bisect bad" as appropriate, and
+continue.
+
+Naming commits
+--------------
+
+We have seen several ways of naming commits already:
+
+ - 40-hexdigit object name
+ - branch name: refers to the commit at the head of the given
+ branch
+ - tag name: refers to the commit pointed to by the given tag
+ (we've seen branches and tags are special cases of
+ <>).
+ - HEAD: refers to the head of the current branch
+
+There are many more; see the "SPECIFYING REVISIONS" section of the
+gitlink:git-rev-parse[1] man page for the complete list of ways to
+name revisions. Some examples:
+
+-------------------------------------------------
+$ git show fb47ddb2 # the first few characters of the object name
+ # are usually enough to specify it uniquely
+$ git show HEAD^ # the parent of the HEAD commit
+$ git show HEAD^^ # the grandparent
+$ git show HEAD~4 # the great-great-grandparent
+-------------------------------------------------
+
+Recall that merge commits may have more than one parent; by default,
+^ and ~ follow the first parent listed in the commit, but you can
+also choose:
+
+-------------------------------------------------
+$ git show HEAD^1 # show the first parent of HEAD
+$ git show HEAD^2 # show the second parent of HEAD
+-------------------------------------------------
+
+In addition to HEAD, there are several other special names for
+commits:
+
+Merges (to be discussed later), as well as operations such as
+git-reset, which change the currently checked-out commit, generally
+set ORIG_HEAD to the value HEAD had before the current operation.
+
+The git-fetch operation always stores the head of the last fetched
+branch in FETCH_HEAD. For example, if you run git fetch without
+specifying a local branch as the target of the operation
+
+-------------------------------------------------
+$ git fetch git://example.com/proj.git theirbranch
+-------------------------------------------------
+
+the fetched commits will still be available from FETCH_HEAD.
+
+When we discuss merges we'll also see the special name MERGE_HEAD,
+which refers to the other branch that we're merging in to the current
+branch.
+
+The gitlink:git-rev-parse[1] command is a low-level command that is
+occasionally useful for translating some name for a commit to the object
+name for that commit:
+
+-------------------------------------------------
+$ git rev-parse origin
+e05db0fd4f31dde7005f075a84f96b360d05984b
+-------------------------------------------------
+
+Creating tags
+-------------
+
+We can also create a tag to refer to a particular commit; after
+running
+
+-------------------------------------------------
+$ git-tag stable-1 1b2e1d63ff
+-------------------------------------------------
+
+You can use stable-1 to refer to the commit 1b2e1d63ff.
+
+This creates a "lightweight" tag. If the tag is a tag you wish to
+share with others, and possibly sign cryptographically, then you
+should create a tag object instead; see the gitlink:git-tag[1] man
+page for details.
+
+Browsing revisions
+------------------
+
+The gitlink:git-log[1] command can show lists of commits. On its
+own, it shows all commits reachable from the parent commit; but you
+can also make more specific requests:
+
+-------------------------------------------------
+$ git log v2.5.. # commits since (not reachable from) v2.5
+$ git log test..master # commits reachable from master but not test
+$ git log master..test # ...reachable from test but not master
+$ git log master...test # ...reachable from either test or master,
+ # but not both
+$ git log --since="2 weeks ago" # commits from the last 2 weeks
+$ git log Makefile # commits which modify Makefile
+$ git log fs/ # ... which modify any file under fs/
+$ git log -S'foo()' # commits which add or remove any file data
+ # matching the string 'foo()'
+-------------------------------------------------
+
+And of course you can combine all of these; the following finds
+commits since v2.5 which touch the Makefile or any file under fs:
+
+-------------------------------------------------
+$ git log v2.5.. Makefile fs/
+-------------------------------------------------
+
+You can also ask git log to show patches:
+
+-------------------------------------------------
+$ git log -p
+-------------------------------------------------
+
+See the "--pretty" option in the gitlink:git-log[1] man page for more
+display options.
+
+Note that git log starts with the most recent commit and works
+backwards through the parents; however, since git history can contain
+multiple independant lines of development, the particular order that
+commits are listed in may be somewhat arbitrary.
+
+Generating diffs
+----------------
+
+You can generate diffs between any two versions using
+gitlink:git-diff[1]:
+
+-------------------------------------------------
+$ git diff master..test
+-------------------------------------------------
+
+Sometimes what you want instead is a set of patches:
+
+-------------------------------------------------
+$ git format-patch master..test
+-------------------------------------------------
+
+will generate a file with a patch for each commit reachable from test
+but not from master. Note that if master also has commits which are
+not reachable from test, then the combined result of these patches
+will not be the same as the diff produced by the git-diff example.
+
+Viewing old file versions
+-------------------------
+
+You can always view an old version of a file by just checking out the
+correct revision first. But sometimes it is more convenient to be
+able to view an old version of a single file without checking
+anything out; this command does that:
+
+-------------------------------------------------
+$ git show v2.5:fs/locks.c
+-------------------------------------------------
+
+Before the colon may be anything that names a commit, and after it
+may be any path to a file tracked by git.
+
+Examples
+--------
+
+Check whether two branches point at the same history
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Suppose you want to check whether two branches point at the same point
+in history.
+
+-------------------------------------------------
+$ git diff origin..master
+-------------------------------------------------
+
+will tell you whether the contents of the project are the same at the
+two branches; in theory, however, it's possible that the same project
+contents could have been arrived at by two different historical
+routes. You could compare the object names:
+
+-------------------------------------------------
+$ git rev-list origin
+e05db0fd4f31dde7005f075a84f96b360d05984b
+$ git rev-list master
+e05db0fd4f31dde7005f075a84f96b360d05984b
+-------------------------------------------------
+
+Or you could recall that the ... operator selects all commits
+contained reachable from either one reference or the other but not
+both: so
+
+-------------------------------------------------
+$ git log origin...master
+-------------------------------------------------
+
+will return no commits when the two branches are equal.
+
+Find first tagged version including a given fix
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Suppose you know that the commit e05db0fd fixed a certain problem.
+You'd like to find the earliest tagged release that contains that
+fix.
+
+Of course, there may be more than one answer--if the history branched
+after commit e05db0fd, then there could be multiple "earliest" tagged
+releases.
+
+You could just visually inspect the commits since e05db0fd:
+
+-------------------------------------------------
+$ gitk e05db0fd..
+-------------------------------------------------
+
+Or you can use gitlink:git-name-rev[1], which will give the commit a
+name based on any tag it finds pointing to one of the commit's
+descendants:
+
+-------------------------------------------------
+$ git name-rev e05db0fd
+e05db0fd tags/v1.5.0-rc1^0~23
+-------------------------------------------------
+
+The gitlink:git-describe[1] command does the opposite, naming the
+revision using a tag on which the given commit is based:
+
+-------------------------------------------------
+$ git describe e05db0fd
+v1.5.0-rc0-ge05db0f
+-------------------------------------------------
+
+but that may sometimes help you guess which tags might come after the
+given commit.
+
+If you just want to verify whether a given tagged version contains a
+given commit, you could use gitlink:git-merge-base[1]:
+
+-------------------------------------------------
+$ git merge-base e05db0fd v1.5.0-rc1
+e05db0fd4f31dde7005f075a84f96b360d05984b
+-------------------------------------------------
+
+The merge-base command finds a common ancestor of the given commits,
+and always returns one or the other in the case where one is a
+descendant of the other; so the above output shows that e05db0fd
+actually is an ancestor of v1.5.0-rc1.
+
+Alternatively, note that
+
+-------------------------------------------------
+$ git log v1.5.0-rc1..e05db0fd
+-------------------------------------------------
+
+will produce empty output if and only if v1.5.0-rc1 includes e05db0fd,
+because it outputs only commits that are not reachable from v1.5.0-rc1.
+
+As yet another alternative, the gitlink:git-show-branch[1] command lists
+the commits reachable from its arguments with a display on the left-hand
+side that indicates which arguments that commit is reachable from. So,
+you can run something like
+
+-------------------------------------------------
+$ git show-branch e05db0fd v1.5.0-rc0 v1.5.0-rc1 v1.5.0-rc2
+! [e05db0fd] Fix warnings in sha1_file.c - use C99 printf format if
+available
+ ! [v1.5.0-rc0] GIT v1.5.0 preview
+ ! [v1.5.0-rc1] GIT v1.5.0-rc1
+ ! [v1.5.0-rc2] GIT v1.5.0-rc2
+...
+-------------------------------------------------
+
+then search for a line that looks like
+
+-------------------------------------------------
++ ++ [e05db0fd] Fix warnings in sha1_file.c - use C99 printf format if
+available
+-------------------------------------------------
+
+Which shows that e05db0fd is reachable from itself, from v1.5.0-rc1, and
+from v1.5.0-rc2, but not from v1.5.0-rc0.
+
+
+Developing with git
+===================
+
+Telling git your name
+---------------------
+
+Before creating any commits, you should introduce yourself to git. The
+easiest way to do so is:
+
+------------------------------------------------
+$ cat >~/.gitconfig <<\EOF
+[user]
+ name = Your Name Comes Here
+ email = you@yourdomain.example.com
+EOF
+------------------------------------------------
+
+(See the "CONFIGURATION FILE" section of gitlink:git-config[1] for
+details on the configuration file.)
+
+
+Creating a new repository
+-------------------------
+
+Creating a new repository from scratch is very easy:
+
+-------------------------------------------------
+$ mkdir project
+$ cd project
+$ git init
+-------------------------------------------------
+
+If you have some initial content (say, a tarball):
+
+-------------------------------------------------
+$ tar -xzvf project.tar.gz
+$ cd project
+$ git init
+$ git add . # include everything below ./ in the first commit:
+$ git commit
+-------------------------------------------------
+
+[[how-to-make-a-commit]]
+how to make a commit
+--------------------
+
+Creating a new commit takes three steps:
+
+ 1. Making some changes to the working directory using your
+ favorite editor.
+ 2. Telling git about your changes.
+ 3. Creating the commit using the content you told git about
+ in step 2.
+
+In practice, you can interleave and repeat steps 1 and 2 as many
+times as you want: in order to keep track of what you want committed
+at step 3, git maintains a snapshot of the tree's contents in a
+special staging area called "the index."
+
+At the beginning, the content of the index will be identical to
+that of the HEAD. The command "git diff --cached", which shows
+the difference between the HEAD and the index, should therefore
+produce no output at that point.
+
+Modifying the index is easy:
+
+To update the index with the new contents of a modified file, use
+
+-------------------------------------------------
+$ git add path/to/file
+-------------------------------------------------
+
+To add the contents of a new file to the index, use
+
+-------------------------------------------------
+$ git add path/to/file
+-------------------------------------------------
+
+To remove a file from the index and from the working tree,
+
+-------------------------------------------------
+$ git rm path/to/file
+-------------------------------------------------
+
+After each step you can verify that
+
+-------------------------------------------------
+$ git diff --cached
+-------------------------------------------------
+
+always shows the difference between the HEAD and the index file--this
+is what you'd commit if you created the commit now--and that
+
+-------------------------------------------------
+$ git diff
+-------------------------------------------------
+
+shows the difference between the working tree and the index file.
+
+Note that "git add" always adds just the current contents of a file
+to the index; further changes to the same file will be ignored unless
+you run git-add on the file again.
+
+When you're ready, just run
+
+-------------------------------------------------
+$ git commit
+-------------------------------------------------
+
+and git will prompt you for a commit message and then create the new
+commmit. Check to make sure it looks like what you expected with
+
+-------------------------------------------------
+$ git show
+-------------------------------------------------
+
+As a special shortcut,
+
+-------------------------------------------------
+$ git commit -a
+-------------------------------------------------
+
+will update the index with any files that you've modified or removed
+and create a commit, all in one step.
+
+A number of commands are useful for keeping track of what you're
+about to commit:
+
+-------------------------------------------------
+$ git diff --cached # difference between HEAD and the index; what
+ # would be commited if you ran "commit" now.
+$ git diff # difference between the index file and your
+ # working directory; changes that would not
+ # be included if you ran "commit" now.
+$ git status # a brief per-file summary of the above.
+-------------------------------------------------
+
+creating good commit messages
+-----------------------------
+
+Though not required, it's a good idea to begin the commit message
+with a single short (less than 50 character) line summarizing the
+change, followed by a blank line and then a more thorough
+description. Tools that turn commits into email, for example, use
+the first line on the Subject line and the rest of the commit in the
+body.
+
+how to merge
+------------
+
+You can rejoin two diverging branches of development using
+gitlink:git-merge[1]:
+
+-------------------------------------------------
+$ git merge branchname
+-------------------------------------------------
+
+merges the development in the branch "branchname" into the current
+branch. If there are conflicts--for example, if the same file is
+modified in two different ways in the remote branch and the local
+branch--then you are warned; the output may look something like this:
+
+-------------------------------------------------
+$ git pull . next
+Trying really trivial in-index merge...
+fatal: Merge requires file-level merging
+Nope.
+Merging HEAD with 77976da35a11db4580b80ae27e8d65caf5208086
+Merging:
+15e2162 world
+77976da goodbye
+found 1 common ancestor(s):
+d122ed4 initial
+Auto-merging file.txt
+CONFLICT (content): Merge conflict in file.txt
+Automatic merge failed; fix conflicts and then commit the result.
+-------------------------------------------------
+
+Conflict markers are left in the problematic files, and after
+you resolve the conflicts manually, you can update the index
+with the contents and run git commit, as you normally would when
+creating a new file.
+
+If you examine the resulting commit using gitk, you will see that it
+has two parents, one pointing to the top of the current branch, and
+one to the top of the other branch.
+
+In more detail:
+
+[[resolving-a-merge]]
+Resolving a merge
+-----------------
+
+When a merge isn't resolved automatically, git leaves the index and
+the working tree in a special state that gives you all the
+information you need to help resolve the merge.
+
+Files with conflicts are marked specially in the index, so until you
+resolve the problem and update the index, git commit will fail:
+
+-------------------------------------------------
+$ git commit
+file.txt: needs merge
+-------------------------------------------------
+
+Also, git status will list those files as "unmerged".
+
+All of the changes that git was able to merge automatically are
+already added to the index file, so gitlink:git-diff[1] shows only
+the conflicts. Also, it uses a somewhat unusual syntax:
+
+-------------------------------------------------
+$ git diff
+diff --cc file.txt
+index 802992c,2b60207..0000000
+--- a/file.txt
++++ b/file.txt
+@@@ -1,1 -1,1 +1,5 @@@
+++<<<<<<< HEAD:file.txt
+ +Hello world
+++=======
++ Goodbye
+++>>>>>>> 77976da35a11db4580b80ae27e8d65caf5208086:file.txt
+-------------------------------------------------
+
+Recall that the commit which will be commited after we resolve this
+conflict will have two parents instead of the usual one: one parent
+will be HEAD, the tip of the current branch; the other will be the
+tip of the other branch, which is stored temporarily in MERGE_HEAD.
+
+The diff above shows the differences between the working-tree version
+of file.txt and two previous version: one version from HEAD, and one
+from MERGE_HEAD. So instead of preceding each line by a single "+"
+or "-", it now uses two columns: the first column is used for
+differences between the first parent and the working directory copy,
+and the second for differences between the second parent and the
+working directory copy. Thus after resolving the conflict in the
+obvious way, the diff will look like:
+
+-------------------------------------------------
+$ git diff
+diff --cc file.txt
+index 802992c,2b60207..0000000
+--- a/file.txt
++++ b/file.txt
+@@@ -1,1 -1,1 +1,1 @@@
+- Hello world
+ -Goodbye
+++Goodbye world
+-------------------------------------------------
+
+This shows that our resolved version deleted "Hello world" from the
+first parent, deleted "Goodbye" from the second parent, and added
+"Goodbye world", which was previously absent from both.
+
+The gitlink:git-log[1] command also provides special help for merges:
+
+-------------------------------------------------
+$ git log --merge
+-------------------------------------------------
+
+This will list all commits which exist only on HEAD or on MERGE_HEAD,
+and which touch an unmerged file.
+
+We can now add the resolved version to the index and commit:
+
+-------------------------------------------------
+$ git add file.txt
+$ git commit
+-------------------------------------------------
+
+Note that the commit message will already be filled in for you with
+some information about the merge. Normally you can just use this
+default message unchanged, but you may add additional commentary of
+your own if desired.
+
+[[undoing-a-merge]]
+undoing a merge
+---------------
+
+If you get stuck and decide to just give up and throw the whole mess
+away, you can always return to the pre-merge state with
+
+-------------------------------------------------
+$ git reset --hard HEAD
+-------------------------------------------------
+
+Or, if you've already commited the merge that you want to throw away,
+
+-------------------------------------------------
+$ git reset --hard HEAD^
+-------------------------------------------------
+
+However, this last command can be dangerous in some cases--never
+throw away a commit you have already committed if that commit may
+itself have been merged into another branch, as doing so may confuse
+further merges.
+
+Fast-forward merges
+-------------------
+
+There is one special case not mentioned above, which is treated
+differently. Normally, a merge results in a merge commit, with two
+parents, one pointing at each of the two lines of development that
+were merged.
+
+However, if one of the two lines of development is completely
+contained within the other--so every commit present in the one is
+already contained in the other--then git just performs a
+<>; the head of the current branch is
+moved forward to point at the head of the merged-in branch, without
+any new commits being created.
+
+Fixing mistakes
+---------------
+
+If you've messed up the working tree, but haven't yet committed your
+mistake, you can return the entire working tree to the last committed
+state with
+
+-------------------------------------------------
+$ git reset --hard HEAD
+-------------------------------------------------
+
+If you make a commit that you later wish you hadn't, there are two
+fundamentally different ways to fix the problem:
+
+ 1. You can create a new commit that undoes whatever was done
+ by the previous commit. This is the correct thing if your
+ mistake has already been made public.
+
+ 2. You can go back and modify the old commit. You should
+ never do this if you have already made the history public;
+ git does not normally expect the "history" of a project to
+ change, and cannot correctly perform repeated merges from
+ a branch that has had its history changed.
+
+Fixing a mistake with a new commit
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Creating a new commit that reverts an earlier change is very easy;
+just pass the gitlink:git-revert[1] command a reference to the bad
+commit; for example, to revert the most recent commit:
+
+-------------------------------------------------
+$ git revert HEAD
+-------------------------------------------------
+
+This will create a new commit which undoes the change in HEAD. You
+will be given a chance to edit the commit message for the new commit.
+
+You can also revert an earlier change, for example, the next-to-last:
+
+-------------------------------------------------
+$ git revert HEAD^
+-------------------------------------------------
+
+In this case git will attempt to undo the old change while leaving
+intact any changes made since then. If more recent changes overlap
+with the changes to be reverted, then you will be asked to fix
+conflicts manually, just as in the case of <>.
+
+Fixing a mistake by editing history
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If the problematic commit is the most recent commit, and you have not
+yet made that commit public, then you may just
+<>.
+
+Alternatively, you
+can edit the working directory and update the index to fix your
+mistake, just as if you were going to <>, then run
+
+-------------------------------------------------
+$ git commit --amend
+-------------------------------------------------
+
+which will replace the old commit by a new commit incorporating your
+changes, giving you a chance to edit the old commit message first.
+
+Again, you should never do this to a commit that may already have
+been merged into another branch; use gitlink:git-revert[1] instead in
+that case.
+
+It is also possible to edit commits further back in the history, but
+this is an advanced topic to be left for
+<>.
+
+Checking out an old version of a file
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In the process of undoing a previous bad change, you may find it
+useful to check out an older version of a particular file using
+gitlink:git-checkout[1]. We've used git checkout before to switch
+branches, but it has quite different behavior if it is given a path
+name: the command
+
+-------------------------------------------------
+$ git checkout HEAD^ path/to/file
+-------------------------------------------------
+
+replaces path/to/file by the contents it had in the commit HEAD^, and
+also updates the index to match. It does not change branches.
+
+If you just want to look at an old version of the file, without
+modifying the working directory, you can do that with
+gitlink:git-show[1]:
+
+-------------------------------------------------
+$ git show HEAD^ path/to/file
+-------------------------------------------------
+
+which will display the given version of the file.
+
+Ensuring good performance
+-------------------------
+
+On large repositories, git depends on compression to keep the history
+information from taking up to much space on disk or in memory.
+
+This compression is not performed automatically. Therefore you
+should occasionally run gitlink:git-gc[1]:
+
+-------------------------------------------------
+$ git gc
+-------------------------------------------------
+
+to recompress the archive. This can be very time-consuming, so
+you may prefer to run git-gc when you are not doing other work.
+
+Ensuring reliability
+--------------------
+
+Checking the repository for corruption
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The gitlink:git-fsck[1] command runs a number of self-consistency checks
+on the repository, and reports on any problems. This may take some
+time. The most common warning by far is about "dangling" objects:
+
+-------------------------------------------------
+$ git fsck
+dangling commit 7281251ddd2a61e38657c827739c57015671a6b3
+dangling commit 2706a059f258c6b245f298dc4ff2ccd30ec21a63
+dangling commit 13472b7c4b80851a1bc551779171dcb03655e9b5
+dangling blob 218761f9d90712d37a9c5e36f406f92202db07eb
+dangling commit bf093535a34a4d35731aa2bd90fe6b176302f14f
+dangling commit 8e4bec7f2ddaa268bef999853c25755452100f8e
+dangling tree d50bb86186bf27b681d25af89d3b5b68382e4085
+dangling tree b24c2473f1fd3d91352a624795be026d64c8841f
+...
+-------------------------------------------------
+
+Dangling objects are objects that are harmless, but also unnecessary;
+you can remove them at any time with gitlink:git-prune[1] or the --prune
+option to gitlink:git-gc[1]:
+
+-------------------------------------------------
+$ git gc --prune
+-------------------------------------------------
+
+This may be time-consuming. Unlike most other git operations (including
+git-gc when run without any options), it is not safe to prune while
+other git operations are in progress in the same repository.
+
+For more about dangling objects, see <>.
+
+
+Recovering lost changes
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Reflogs
+^^^^^^^
+
+Say you modify a branch with gitlink:git-reset[1] --hard, and then
+realize that the branch was the only reference you had to that point in
+history.
+
+Fortunately, git also keeps a log, called a "reflog", of all the
+previous values of each branch. So in this case you can still find the
+old history using, for example,
+
+-------------------------------------------------
+$ git log master@{1}
+-------------------------------------------------
+
+This lists the commits reachable from the previous version of the head.
+This syntax can be used to with any git command that accepts a commit,
+not just with git log. Some other examples:
+
+-------------------------------------------------
+$ git show master@{2} # See where the branch pointed 2,
+$ git show master@{3} # 3, ... changes ago.
+$ gitk master@{yesterday} # See where it pointed yesterday,
+$ gitk master@{"1 week ago"} # ... or last week
+-------------------------------------------------
+
+The reflogs are kept by default for 30 days, after which they may be
+pruned. See gitlink:git-reflog[1] and gitlink:git-gc[1] to learn
+how to control this pruning, and see the "SPECIFYING REVISIONS"
+section of gitlink:git-rev-parse[1] for details.
+
+Note that the reflog history is very different from normal git history.
+While normal history is shared by every repository that works on the
+same project, the reflog history is not shared: it tells you only about
+how the branches in your local repository have changed over time.
+
+Examining dangling objects
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In some situations the reflog may not be able to save you. For
+example, suppose you delete a branch, then realize you need the history
+it pointed you. The reflog is also deleted; however, if you have not
+yet pruned the repository, then you may still be able to find
+the lost commits; run git-fsck and watch for output that mentions
+"dangling commits":
+
+-------------------------------------------------
+$ git fsck
+dangling commit 7281251ddd2a61e38657c827739c57015671a6b3
+dangling commit 2706a059f258c6b245f298dc4ff2ccd30ec21a63
+dangling commit 13472b7c4b80851a1bc551779171dcb03655e9b5
+...
+-------------------------------------------------
+
+and watch for output that mentions "dangling commits". You can examine
+one of those dangling commits with, for example,
+
+------------------------------------------------
+$ gitk 7281251ddd --not --all
+------------------------------------------------
+
+which does what it sounds like: it says that you want to see the commit
+history that is described by the dangling commit(s), but not the
+history that is described by all your existing branches and tags. Thus
+you get exactly the history reachable from that commit that is lost.
+(And notice that it might not be just one commit: we only report the
+"tip of the line" as being dangling, but there might be a whole deep
+and complex commit history that was gotten dropped.)
+
+If you decide you want the history back, you can always create a new
+reference pointing to it, for example, a new branch:
+
+------------------------------------------------
+$ git branch recovered-branch 7281251ddd
+------------------------------------------------
+
+
+Sharing development with others
+===============================
+
+[[getting-updates-with-git-pull]]
+Getting updates with git pull
+-----------------------------
+
+After you clone a repository and make a few changes of your own, you
+may wish to check the original repository for updates and merge them
+into your own work.
+
+We have already seen <> with gitlink:git-fetch[1],
+and how to merge two branches. So you can merge in changes from the
+original repository's master branch with:
+
+-------------------------------------------------
+$ git fetch
+$ git merge origin/master
+-------------------------------------------------
+
+However, the gitlink:git-pull[1] command provides a way to do this in
+one step:
+
+-------------------------------------------------
+$ git pull origin master
+-------------------------------------------------
+
+In fact, "origin" is normally the default repository to pull from,
+and the default branch is normally the HEAD of the remote repository,
+so often you can accomplish the above with just
+
+-------------------------------------------------
+$ git pull
+-------------------------------------------------
+
+See the descriptions of the branch..remote and
+branch..merge options in gitlink:git-config[1] to learn
+how to control these defaults depending on the current branch.
+
+In addition to saving you keystrokes, "git pull" also helps you by
+producing a default commit message documenting the branch and
+repository that you pulled from.
+
+(But note that no such commit will be created in the case of a
+<>; instead, your branch will just be
+updated to point to the latest commit from the upstream branch).
+
+The git-pull command can also be given "." as the "remote" repository,
+in which case it just merges in a branch from the current repository; so
+the commands
+
+-------------------------------------------------
+$ git pull . branch
+$ git merge branch
+-------------------------------------------------
+
+are roughly equivalent. The former is actually very commonly used.
+
+Submitting patches to a project
+-------------------------------
+
+If you just have a few changes, the simplest way to submit them may
+just be to send them as patches in email:
+
+First, use gitlink:git-format-patch[1]; for example:
+
+-------------------------------------------------
+$ git format-patch origin
+-------------------------------------------------
+
+will produce a numbered series of files in the current directory, one
+for each patch in the current branch but not in origin/HEAD.
+
+You can then import these into your mail client and send them by
+hand. However, if you have a lot to send at once, you may prefer to
+use the gitlink:git-send-email[1] script to automate the process.
+Consult the mailing list for your project first to determine how they
+prefer such patches be handled.
+
+Importing patches to a project
+------------------------------
+
+Git also provides a tool called gitlink:git-am[1] (am stands for
+"apply mailbox"), for importing such an emailed series of patches.
+Just save all of the patch-containing messages, in order, into a
+single mailbox file, say "patches.mbox", then run
+
+-------------------------------------------------
+$ git am -3 patches.mbox
+-------------------------------------------------
+
+Git will apply each patch in order; if any conflicts are found, it
+will stop, and you can fix the conflicts as described in
+"<>". (The "-3" option tells
+git to perform a merge; if you would prefer it just to abort and
+leave your tree and index untouched, you may omit that option.)
+
+Once the index is updated with the results of the conflict
+resolution, instead of creating a new commit, just run
+
+-------------------------------------------------
+$ git am --resolved
+-------------------------------------------------
+
+and git will create the commit for you and continue applying the
+remaining patches from the mailbox.
+
+The final result will be a series of commits, one for each patch in
+the original mailbox, with authorship and commit log message each
+taken from the message containing each patch.
+
+[[setting-up-a-public-repository]]
+Setting up a public repository
+------------------------------
+
+Another way to submit changes to a project is to simply tell the
+maintainer of that project to pull from your repository, exactly as
+you did in the section "<>".
+
+If you and maintainer both have accounts on the same machine, then
+then you can just pull changes from each other's repositories
+directly; note that all of the command (gitlink:git-clone[1],
+git-fetch[1], git-pull[1], etc.) which accept a URL as an argument
+will also accept a local file patch; so, for example, you can
+use
+
+-------------------------------------------------
+$ git clone /path/to/repository
+$ git pull /path/to/other/repository
+-------------------------------------------------
+
+If this sort of setup is inconvenient or impossible, another (more
+common) option is to set up a public repository on a public server.
+This also allows you to cleanly separate private work in progress
+from publicly visible work.
+
+You will continue to do your day-to-day work in your personal
+repository, but periodically "push" changes from your personal
+repository into your public repository, allowing other developers to
+pull from that repository. So the flow of changes, in a situation
+where there is one other developer with a public repository, looks
+like this:
+
+ you push
+ your personal repo ------------------> your public repo
+ ^ |
+ | |
+ | you pull | they pull
+ | |
+ | |
+ | they push V
+ their public repo <------------------- their repo
+
+Now, assume your personal repository is in the directory ~/proj. We
+first create a new clone of the repository:
+
+-------------------------------------------------
+$ git clone --bare proj-clone.git
+-------------------------------------------------
+
+The resulting directory proj-clone.git will contains a "bare" git
+repository--it is just the contents of the ".git" directory, without
+a checked-out copy of a working directory.
+
+Next, copy proj-clone.git to the server where you plan to host the
+public repository. You can use scp, rsync, or whatever is most
+convenient.
+
+If somebody else maintains the public server, they may already have
+set up a git service for you, and you may skip to the section
+"<>", below.
+
+Otherwise, the following sections explain how to export your newly
+created public repository:
+
+[[exporting-via-http]]
+Exporting a git repository via http
+-----------------------------------
+
+The git protocol gives better performance and reliability, but on a
+host with a web server set up, http exports may be simpler to set up.
+
+All you need to do is place the newly created bare git repository in
+a directory that is exported by the web server, and make some
+adjustments to give web clients some extra information they need:
+
+-------------------------------------------------
+$ mv proj.git /home/you/public_html/proj.git
+$ cd proj.git
+$ git update-server-info
+$ chmod a+x hooks/post-update
+-------------------------------------------------
+
+(For an explanation of the last two lines, see
+gitlink:git-update-server-info[1], and the documentation
+link:hooks.txt[Hooks used by git].)
+
+Advertise the url of proj.git. Anybody else should then be able to
+clone or pull from that url, for example with a commandline like:
+
+-------------------------------------------------
+$ git clone http://yourserver.com/~you/proj.git
+-------------------------------------------------
+
+(See also
+link:howto/setup-git-server-over-http.txt[setup-git-server-over-http]
+for a slightly more sophisticated setup using WebDAV which also
+allows pushing over http.)
+
+[[exporting-via-git]]
+Exporting a git repository via the git protocol
+-----------------------------------------------
+
+This is the preferred method.
+
+For now, we refer you to the gitlink:git-daemon[1] man page for
+instructions. (See especially the examples section.)
+
+[[pushing-changes-to-a-public-repository]]
+Pushing changes to a public repository
+--------------------------------------
+
+Note that the two techniques outline above (exporting via
+<> or <>) allow other
+maintainers to fetch your latest changes, but they do not allow write
+access, which you will need to update the public repository with the
+latest changes created in your private repository.
+
+The simplest way to do this is using gitlink:git-push[1] and ssh; to
+update the remote branch named "master" with the latest state of your
+branch named "master", run
+
+-------------------------------------------------
+$ git push ssh://yourserver.com/~you/proj.git master:master
+-------------------------------------------------
+
+or just
+
+-------------------------------------------------
+$ git push ssh://yourserver.com/~you/proj.git master
+-------------------------------------------------
+
+As with git-fetch, git-push will complain if this does not result in
+a <>. Normally this is a sign of
+something wrong. However, if you are sure you know what you're
+doing, you may force git-push to perform the update anyway by
+proceeding the branch name by a plus sign:
+
+-------------------------------------------------
+$ git push ssh://yourserver.com/~you/proj.git +master
+-------------------------------------------------
+
+As with git-fetch, you may also set up configuration options to
+save typing; so, for example, after
+
+-------------------------------------------------
+$ cat >.git/config <.url, branch..remote,
+and remote..push options in gitlink:git-config[1] for
+details.
+
+Setting up a shared repository
+------------------------------
+
+Another way to collaborate is by using a model similar to that
+commonly used in CVS, where several developers with special rights
+all push to and pull from a single shared repository. See
+link:cvs-migration.txt[git for CVS users] for instructions on how to
+set this up.
+
+Allow web browsing of a repository
+----------------------------------
+
+The gitweb cgi script provides users an easy way to browse your
+project's files and history without having to install git; see the file
+gitweb/README in the git source tree for instructions on setting it up.
+
+Examples
+--------
+
+TODO: topic branches, typical roles as in everyday.txt, ?
+
+
+[[cleaning-up-history]]
+Rewriting history and maintaining patch series
+==============================================
+
+Normally commits are only added to a project, never taken away or
+replaced. Git is designed with this assumption, and violating it will
+cause git's merge machinery (for example) to do the wrong thing.
+
+However, there is a situation in which it can be useful to violate this
+assumption.
+
+Creating the perfect patch series
+---------------------------------
+
+Suppose you are a contributor to a large project, and you want to add a
+complicated feature, and to present it to the other developers in a way
+that makes it easy for them to read your changes, verify that they are
+correct, and understand why you made each change.
+
+If you present all of your changes as a single patch (or commit), they
+may find it is too much to digest all at once.
+
+If you present them with the entire history of your work, complete with
+mistakes, corrections, and dead ends, they may be overwhelmed.
+
+So the ideal is usually to produce a series of patches such that:
+
+ 1. Each patch can be applied in order.
+
+ 2. Each patch includes a single logical change, together with a
+ message explaining the change.
+
+ 3. No patch introduces a regression: after applying any initial
+ part of the series, the resulting project still compiles and
+ works, and has no bugs that it didn't have before.
+
+ 4. The complete series produces the same end result as your own
+ (probably much messier!) development process did.
+
+We will introduce some tools that can help you do this, explain how to
+use them, and then explain some of the problems that can arise because
+you are rewriting history.
+
+Keeping a patch series up to date using git-rebase
+--------------------------------------------------
+
+Suppose you have a series of commits in a branch "mywork", which
+originally branched off from "origin".
+
+Suppose you create a branch "mywork" on a remote-tracking branch
+"origin", and created some commits on top of it:
+
+-------------------------------------------------
+$ git checkout -b mywork origin
+$ vi file.txt
+$ git commit
+$ vi otherfile.txt
+$ git commit
+...
+-------------------------------------------------
+
+You have performed no merges into mywork, so it is just a simple linear
+sequence of patches on top of "origin":
+
+
+ o--o--o <-- origin
+ \
+ o--o--o <-- mywork
+
+Some more interesting work has been done in the upstream project, and
+"origin" has advanced:
+
+ o--o--O--o--o--o <-- origin
+ \
+ a--b--c <-- mywork
+
+At this point, you could use "pull" to merge your changes back in;
+the result would create a new merge commit, like this:
+
+
+ o--o--O--o--o--o <-- origin
+ \ \
+ a--b--c--m <-- mywork
+
+However, if you prefer to keep the history in mywork a simple series of
+commits without any merges, you may instead choose to use
+gitlink:git-rebase[1]:
+
+-------------------------------------------------
+$ git checkout mywork
+$ git rebase origin
+-------------------------------------------------
+
+This will remove each of your commits from mywork, temporarily saving
+them as patches (in a directory named ".dotest"), update mywork to
+point at the latest version of origin, then apply each of the saved
+patches to the new mywork. The result will look like:
+
+
+ o--o--O--o--o--o <-- origin
+ \
+ a'--b'--c' <-- mywork
+
+In the process, it may discover conflicts. In that case it will stop
+and allow you to fix the conflicts; after fixing conflicts, use "git
+add" to update the index with those contents, and then, instead of
+running git-commit, just run
+
+-------------------------------------------------
+$ git rebase --continue
+-------------------------------------------------
+
+and git will continue applying the rest of the patches.
+
+At any point you may use the --abort option to abort this process and
+return mywork to the state it had before you started the rebase:
+
+-------------------------------------------------
+$ git rebase --abort
+-------------------------------------------------
+
+Reordering or selecting from a patch series
+-------------------------------------------
+
+Given one existing commit, the gitlink:git-cherry-pick[1] command
+allows you to apply the change introduced by that commit and create a
+new commit that records it. So, for example, if "mywork" points to a
+series of patches on top of "origin", you might do something like:
+
+-------------------------------------------------
+$ git checkout -b mywork-new origin
+$ gitk origin..mywork &
+-------------------------------------------------
+
+And browse through the list of patches in the mywork branch using gitk,
+applying them (possibly in a different order) to mywork-new using
+cherry-pick, and possibly modifying them as you go using commit
+--amend.
+
+Another technique is to use git-format-patch to create a series of
+patches, then reset the state to before the patches:
+
+-------------------------------------------------
+$ git format-patch origin
+$ git reset --hard origin
+-------------------------------------------------
+
+Then modify, reorder, or eliminate patches as preferred before applying
+them again with gitlink:git-am[1].
+
+Other tools
+-----------
+
+There are numerous other tools, such as stgit, which exist for the
+purpose of maintaining a patch series. These are out of the scope of
+this manual.
+
+Problems with rewriting history
+-------------------------------
+
+The primary problem with rewriting the history of a branch has to do
+with merging. Suppose somebody fetches your branch and merges it into
+their branch, with a result something like this:
+
+ o--o--O--o--o--o <-- origin
+ \ \
+ t--t--t--m <-- their branch:
+
+Then suppose you modify the last three commits:
+
+ o--o--o <-- new head of origin
+ /
+ o--o--O--o--o--o <-- old head of origin
+
+If we examined all this history together in one repository, it will
+look like:
+
+ o--o--o <-- new head of origin
+ /
+ o--o--O--o--o--o <-- old head of origin
+ \ \
+ t--t--t--m <-- their branch:
+
+Git has no way of knowing that the new head is an updated version of
+the old head; it treats this situation exactly the same as it would if
+two developers had independently done the work on the old and new heads
+in parallel. At this point, if someone attempts to merge the new head
+in to their branch, git will attempt to merge together the two (old and
+new) lines of development, instead of trying to replace the old by the
+new. The results are likely to be unexpected.
+
+You may still choose to publish branches whose history is rewritten,
+and it may be useful for others to be able to fetch those branches in
+order to examine or test them, but they should not attempt to pull such
+branches into their own work.
+
+For true distributed development that supports proper merging,
+published branches should never be rewritten.
+
+Advanced branch management
+==========================
+
+Fetching individual branches
+----------------------------
+
+Instead of using gitlink:git-remote[1], you can also choose just
+to update one branch at a time, and to store it locally under an
+arbitrary name:
+
+-------------------------------------------------
+$ git fetch origin todo:my-todo-work
+-------------------------------------------------
+
+The first argument, "origin", just tells git to fetch from the
+repository you originally cloned from. The second argument tells git
+to fetch the branch named "todo" from the remote repository, and to
+store it locally under the name refs/heads/my-todo-work.
+
+You can also fetch branches from other repositories; so
+
+-------------------------------------------------
+$ git fetch git://example.com/proj.git master:example-master
+-------------------------------------------------
+
+will create a new branch named "example-master" and store in it the
+branch named "master" from the repository at the given URL. If you
+already have a branch named example-master, it will attempt to
+"fast-forward" to the commit given by example.com's master branch. So
+next we explain what a fast-forward is:
+
+[[fast-forwards]]
+Understanding git history: fast-forwards
+----------------------------------------
+
+In the previous example, when updating an existing branch, "git
+fetch" checks to make sure that the most recent commit on the remote
+branch is a descendant of the most recent commit on your copy of the
+branch before updating your copy of the branch to point at the new
+commit. Git calls this process a "fast forward".
+
+A fast forward looks something like this:
+
+ o--o--o--o <-- old head of the branch
+ \
+ o--o--o <-- new head of the branch
+
+
+In some cases it is possible that the new head will *not* actually be
+a descendant of the old head. For example, the developer may have
+realized she made a serious mistake, and decided to backtrack,
+resulting in a situation like:
+
+ o--o--o--o--a--b <-- old head of the branch
+ \
+ o--o--o <-- new head of the branch
+
+
+
+In this case, "git fetch" will fail, and print out a warning.
+
+In that case, you can still force git to update to the new head, as
+described in the following section. However, note that in the
+situation above this may mean losing the commits labeled "a" and "b",
+unless you've already created a reference of your own pointing to
+them.
+
+Forcing git fetch to do non-fast-forward updates
+------------------------------------------------
+
+If git fetch fails because the new head of a branch is not a
+descendant of the old head, you may force the update with:
+
+-------------------------------------------------
+$ git fetch git://example.com/proj.git +master:refs/remotes/example/master
+-------------------------------------------------
+
+Note the addition of the "+" sign. Be aware that commits which the
+old version of example/master pointed at may be lost, as we saw in
+the previous section.
+
+Configuring remote branches
+---------------------------
+
+We saw above that "origin" is just a shortcut to refer to the
+repository which you originally cloned from. This information is
+stored in git configuration variables, which you can see using
+gitlink:git-config[1]:
+
+-------------------------------------------------
+$ git config -l
+core.repositoryformatversion=0
+core.filemode=true
+core.logallrefupdates=true
+remote.origin.url=git://git.kernel.org/pub/scm/git/git.git
+remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
+branch.master.remote=origin
+branch.master.merge=refs/heads/master
+-------------------------------------------------
+
+If there are other repositories that you also use frequently, you can
+create similar configuration options to save typing; for example,
+after
+
+-------------------------------------------------
+$ git config remote.example.url git://example.com/proj.git
+-------------------------------------------------
+
+then the following two commands will do the same thing:
+
+-------------------------------------------------
+$ git fetch git://example.com/proj.git master:refs/remotes/example/master
+$ git fetch example master:refs/remotes/example/master
+-------------------------------------------------
+
+Even better, if you add one more option:
+
+-------------------------------------------------
+$ git config remote.example.fetch master:refs/remotes/example/master
+-------------------------------------------------
+
+then the following commands will all do the same thing:
+
+-------------------------------------------------
+$ git fetch git://example.com/proj.git master:ref/remotes/example/master
+$ git fetch example master:ref/remotes/example/master
+$ git fetch example example/master
+$ git fetch example
+-------------------------------------------------
+
+You can also add a "+" to force the update each time:
+
+-------------------------------------------------
+$ git config remote.example.fetch +master:ref/remotes/example/master
+-------------------------------------------------
+
+Don't do this unless you're sure you won't mind "git fetch" possibly
+throwing away commits on mybranch.
+
+Also note that all of the above configuration can be performed by
+directly editing the file .git/config instead of using
+gitlink:git-config[1].
+
+See gitlink:git-config[1] for more details on the configuration
+options mentioned above.
+
+
+Git internals
+=============
+
+There are two object abstractions: the "object database", and the
+"current directory cache" aka "index".
+
+The Object Database
+-------------------
+
+The object database is literally just a content-addressable collection
+of objects. All objects are named by their content, which is
+approximated by the SHA1 hash of the object itself. Objects may refer
+to other objects (by referencing their SHA1 hash), and so you can
+build up a hierarchy of objects.
+
+All objects have a statically determined "type" aka "tag", which is
+determined at object creation time, and which identifies the format of
+the object (i.e. how it is used, and how it can refer to other
+objects). There are currently four different object types: "blob",
+"tree", "commit" and "tag".
+
+A "blob" object cannot refer to any other object, and is, like the type
+implies, a pure storage object containing some user data. It is used to
+actually store the file data, i.e. a blob object is associated with some
+particular version of some file.
+
+A "tree" object is an object that ties one or more "blob" objects into a
+directory structure. In addition, a tree object can refer to other tree
+objects, thus creating a directory hierarchy.
+
+A "commit" object ties such directory hierarchies together into
+a DAG of revisions - each "commit" is associated with exactly one tree
+(the directory hierarchy at the time of the commit). In addition, a
+"commit" refers to one or more "parent" commit objects that describe the
+history of how we arrived at that directory hierarchy.
+
+As a special case, a commit object with no parents is called the "root"
+object, and is the point of an initial project commit. Each project
+must have at least one root, and while you can tie several different
+root objects together into one project by creating a commit object which
+has two or more separate roots as its ultimate parents, that's probably
+just going to confuse people. So aim for the notion of "one root object
+per project", even if git itself does not enforce that.
+
+A "tag" object symbolically identifies and can be used to sign other
+objects. It contains the identifier and type of another object, a
+symbolic name (of course!) and, optionally, a signature.
+
+Regardless of object type, all objects share the following
+characteristics: they are all deflated with zlib, and have a header
+that not only specifies their type, but also provides size information
+about the data in the object. It's worth noting that the SHA1 hash
+that is used to name the object is the hash of the original data
+plus this header, so `sha1sum` 'file' does not match the object name
+for 'file'.
+(Historical note: in the dawn of the age of git the hash
+was the sha1 of the 'compressed' object.)
+
+As a result, the general consistency of an object can always be tested
+independently of the contents or the type of the object: all objects can
+be validated by verifying that (a) their hashes match the content of the
+file and (b) the object successfully inflates to a stream of bytes that
+forms a sequence of + + + + .
+
+The structured objects can further have their structure and
+connectivity to other objects verified. This is generally done with
+the `git-fsck` program, which generates a full dependency graph
+of all objects, and verifies their internal consistency (in addition
+to just verifying their superficial consistency through the hash).
+
+The object types in some more detail:
+
+Blob Object
+-----------
+
+A "blob" object is nothing but a binary blob of data, and doesn't
+refer to anything else. There is no signature or any other
+verification of the data, so while the object is consistent (it 'is'
+indexed by its sha1 hash, so the data itself is certainly correct), it
+has absolutely no other attributes. No name associations, no
+permissions. It is purely a blob of data (i.e. normally "file
+contents").
+
+In particular, since the blob is entirely defined by its data, if two
+files in a directory tree (or in multiple different versions of the
+repository) have the same contents, they will share the same blob
+object. The object is totally independent of its location in the
+directory tree, and renaming a file does not change the object that
+file is associated with in any way.
+
+A blob is typically created when gitlink:git-update-index[1]
+is run, and its data can be accessed by gitlink:git-cat-file[1].
+
+Tree Object
+-----------
+
+The next hierarchical object type is the "tree" object. A tree object
+is a list of mode/name/blob data, sorted by name. Alternatively, the
+mode data may specify a directory mode, in which case instead of
+naming a blob, that name is associated with another TREE object.
+
+Like the "blob" object, a tree object is uniquely determined by the
+set contents, and so two separate but identical trees will always
+share the exact same object. This is true at all levels, i.e. it's
+true for a "leaf" tree (which does not refer to any other trees, only
+blobs) as well as for a whole subdirectory.
+
+For that reason a "tree" object is just a pure data abstraction: it
+has no history, no signatures, no verification of validity, except
+that since the contents are again protected by the hash itself, we can
+trust that the tree is immutable and its contents never change.
+
+So you can trust the contents of a tree to be valid, the same way you
+can trust the contents of a blob, but you don't know where those
+contents 'came' from.
+
+Side note on trees: since a "tree" object is a sorted list of
+"filename+content", you can create a diff between two trees without
+actually having to unpack two trees. Just ignore all common parts,
+and your diff will look right. In other words, you can effectively
+(and efficiently) tell the difference between any two random trees by
+O(n) where "n" is the size of the difference, rather than the size of
+the tree.
+
+Side note 2 on trees: since the name of a "blob" depends entirely and
+exclusively on its contents (i.e. there are no names or permissions
+involved), you can see trivial renames or permission changes by
+noticing that the blob stayed the same. However, renames with data
+changes need a smarter "diff" implementation.
+
+A tree is created with gitlink:git-write-tree[1] and
+its data can be accessed by gitlink:git-ls-tree[1].
+Two trees can be compared with gitlink:git-diff-tree[1].
+
+Commit Object
+-------------
+
+The "commit" object is an object that introduces the notion of
+history into the picture. In contrast to the other objects, it
+doesn't just describe the physical state of a tree, it describes how
+we got there, and why.
+
+A "commit" is defined by the tree-object that it results in, the
+parent commits (zero, one or more) that led up to that point, and a
+comment on what happened. Again, a commit is not trusted per se:
+the contents are well-defined and "safe" due to the cryptographically
+strong signatures at all levels, but there is no reason to believe
+that the tree is "good" or that the merge information makes sense.
+The parents do not have to actually have any relationship with the
+result, for example.
+
+Note on commits: unlike real SCM's, commits do not contain
+rename information or file mode change information. All of that is
+implicit in the trees involved (the result tree, and the result trees
+of the parents), and describing that makes no sense in this idiotic
+file manager.
+
+A commit is created with gitlink:git-commit-tree[1] and
+its data can be accessed by gitlink:git-cat-file[1].
+
+Trust
+-----
+
+An aside on the notion of "trust". Trust is really outside the scope
+of "git", but it's worth noting a few things. First off, since
+everything is hashed with SHA1, you 'can' trust that an object is
+intact and has not been messed with by external sources. So the name
+of an object uniquely identifies a known state - just not a state that
+you may want to trust.
+
+Furthermore, since the SHA1 signature of a commit refers to the
+SHA1 signatures of the tree it is associated with and the signatures
+of the parent, a single named commit specifies uniquely a whole set
+of history, with full contents. You can't later fake any step of the
+way once you have the name of a commit.
+
+So to introduce some real trust in the system, the only thing you need
+to do is to digitally sign just 'one' special note, which includes the
+name of a top-level commit. Your digital signature shows others
+that you trust that commit, and the immutability of the history of
+commits tells others that they can trust the whole history.
+
+In other words, you can easily validate a whole archive by just
+sending out a single email that tells the people the name (SHA1 hash)
+of the top commit, and digitally sign that email using something
+like GPG/PGP.
+
+To assist in this, git also provides the tag object...
+
+Tag Object
+----------
+
+Git provides the "tag" object to simplify creating, managing and
+exchanging symbolic and signed tokens. The "tag" object at its
+simplest simply symbolically identifies another object by containing
+the sha1, type and symbolic name.
+
+However it can optionally contain additional signature information
+(which git doesn't care about as long as there's less than 8k of
+it). This can then be verified externally to git.
+
+Note that despite the tag features, "git" itself only handles content
+integrity; the trust framework (and signature provision and
+verification) has to come from outside.
+
+A tag is created with gitlink:git-mktag[1],
+its data can be accessed by gitlink:git-cat-file[1],
+and the signature can be verified by
+gitlink:git-verify-tag[1].
+
+
+The "index" aka "Current Directory Cache"
+-----------------------------------------
+
+The index is a simple binary file, which contains an efficient
+representation of a virtual directory content at some random time. It
+does so by a simple array that associates a set of names, dates,
+permissions and content (aka "blob") objects together. The cache is
+always kept ordered by name, and names are unique (with a few very
+specific rules) at any point in time, but the cache has no long-term
+meaning, and can be partially updated at any time.
+
+In particular, the index certainly does not need to be consistent with
+the current directory contents (in fact, most operations will depend on
+different ways to make the index 'not' be consistent with the directory
+hierarchy), but it has three very important attributes:
+
+'(a) it can re-generate the full state it caches (not just the
+directory structure: it contains pointers to the "blob" objects so
+that it can regenerate the data too)'
+
+As a special case, there is a clear and unambiguous one-way mapping
+from a current directory cache to a "tree object", which can be
+efficiently created from just the current directory cache without
+actually looking at any other data. So a directory cache at any one
+time uniquely specifies one and only one "tree" object (but has
+additional data to make it easy to match up that tree object with what
+has happened in the directory)
+
+'(b) it has efficient methods for finding inconsistencies between that
+cached state ("tree object waiting to be instantiated") and the
+current state.'
+
+'(c) it can additionally efficiently represent information about merge
+conflicts between different tree objects, allowing each pathname to be
+associated with sufficient information about the trees involved that
+you can create a three-way merge between them.'
+
+Those are the three ONLY things that the directory cache does. It's a
+cache, and the normal operation is to re-generate it completely from a
+known tree object, or update/compare it with a live tree that is being
+developed. If you blow the directory cache away entirely, you generally
+haven't lost any information as long as you have the name of the tree
+that it described.
+
+At the same time, the index is at the same time also the
+staging area for creating new trees, and creating a new tree always
+involves a controlled modification of the index file. In particular,
+the index file can have the representation of an intermediate tree that
+has not yet been instantiated. So the index can be thought of as a
+write-back cache, which can contain dirty information that has not yet
+been written back to the backing store.
+
+
+
+The Workflow
+------------
+
+Generally, all "git" operations work on the index file. Some operations
+work *purely* on the index file (showing the current state of the
+index), but most operations move data to and from the index file. Either
+from the database or from the working directory. Thus there are four
+main combinations:
+
+working directory -> index
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You update the index with information from the working directory with
+the gitlink:git-update-index[1] command. You
+generally update the index information by just specifying the filename
+you want to update, like so:
+
+-------------------------------------------------
+$ git-update-index filename
+-------------------------------------------------
+
+but to avoid common mistakes with filename globbing etc, the command
+will not normally add totally new entries or remove old entries,
+i.e. it will normally just update existing cache entries.
+
+To tell git that yes, you really do realize that certain files no
+longer exist, or that new files should be added, you
+should use the `--remove` and `--add` flags respectively.
+
+NOTE! A `--remove` flag does 'not' mean that subsequent filenames will
+necessarily be removed: if the files still exist in your directory
+structure, the index will be updated with their new status, not
+removed. The only thing `--remove` means is that update-cache will be
+considering a removed file to be a valid thing, and if the file really
+does not exist any more, it will update the index accordingly.
+
+As a special case, you can also do `git-update-index --refresh`, which
+will refresh the "stat" information of each index to match the current
+stat information. It will 'not' update the object status itself, and
+it will only update the fields that are used to quickly test whether
+an object still matches its old backing store object.
+
+index -> object database
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+You write your current index file to a "tree" object with the program
+
+-------------------------------------------------
+$ git-write-tree
+-------------------------------------------------
+
+that doesn't come with any options - it will just write out the
+current index into the set of tree objects that describe that state,
+and it will return the name of the resulting top-level tree. You can
+use that tree to re-generate the index at any time by going in the
+other direction:
+
+object database -> index
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+You read a "tree" file from the object database, and use that to
+populate (and overwrite - don't do this if your index contains any
+unsaved state that you might want to restore later!) your current
+index. Normal operation is just
+
+-------------------------------------------------
+$ git-read-tree
+-------------------------------------------------
+
+and your index file will now be equivalent to the tree that you saved
+earlier. However, that is only your 'index' file: your working
+directory contents have not been modified.
+
+index -> working directory
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You update your working directory from the index by "checking out"
+files. This is not a very common operation, since normally you'd just
+keep your files updated, and rather than write to your working
+directory, you'd tell the index files about the changes in your
+working directory (i.e. `git-update-index`).
+
+However, if you decide to jump to a new version, or check out somebody
+else's version, or just restore a previous tree, you'd populate your
+index file with read-tree, and then you need to check out the result
+with
+
+-------------------------------------------------
+$ git-checkout-index filename
+-------------------------------------------------
+
+or, if you want to check out all of the index, use `-a`.
+
+NOTE! git-checkout-index normally refuses to overwrite old files, so
+if you have an old version of the tree already checked out, you will
+need to use the "-f" flag ('before' the "-a" flag or the filename) to
+'force' the checkout.
+
+
+Finally, there are a few odds and ends which are not purely moving
+from one representation to the other:
+
+Tying it all together
+~~~~~~~~~~~~~~~~~~~~~
+
+To commit a tree you have instantiated with "git-write-tree", you'd
+create a "commit" object that refers to that tree and the history
+behind it - most notably the "parent" commits that preceded it in
+history.
+
+Normally a "commit" has one parent: the previous state of the tree
+before a certain change was made. However, sometimes it can have two
+or more parent commits, in which case we call it a "merge", due to the
+fact that such a commit brings together ("merges") two or more
+previous states represented by other commits.
+
+In other words, while a "tree" represents a particular directory state
+of a working directory, a "commit" represents that state in "time",
+and explains how we got there.
+
+You create a commit object by giving it the tree that describes the
+state at the time of the commit, and a list of parents:
+
+-------------------------------------------------
+$ git-commit-tree -p [-p ..]
+-------------------------------------------------
+
+and then giving the reason for the commit on stdin (either through
+redirection from a pipe or file, or by just typing it at the tty).
+
+git-commit-tree will return the name of the object that represents
+that commit, and you should save it away for later use. Normally,
+you'd commit a new `HEAD` state, and while git doesn't care where you
+save the note about that state, in practice we tend to just write the
+result to the file pointed at by `.git/HEAD`, so that we can always see
+what the last committed state was.
+
+Here is an ASCII art by Jon Loeliger that illustrates how
+various pieces fit together.
+
+------------
+
+ commit-tree
+ commit obj
+ +----+
+ | |
+ | |
+ V V
+ +-----------+
+ | Object DB |
+ | Backing |
+ | Store |
+ +-----------+
+ ^
+ write-tree | |
+ tree obj | |
+ | | read-tree
+ | | tree obj
+ V
+ +-----------+
+ | Index |
+ | "cache" |
+ +-----------+
+ update-index ^
+ blob obj | |
+ | |
+ checkout-index -u | | checkout-index
+ stat | | blob obj
+ V
+ +-----------+
+ | Working |
+ | Directory |
+ +-----------+
+
+------------
+
+
+Examining the data
+------------------
+
+You can examine the data represented in the object database and the
+index with various helper tools. For every object, you can use
+gitlink:git-cat-file[1] to examine details about the
+object:
+
+-------------------------------------------------
+$ git-cat-file -t
+-------------------------------------------------
+
+shows the type of the object, and once you have the type (which is
+usually implicit in where you find the object), you can use
+
+-------------------------------------------------
+$ git-cat-file blob|tree|commit|tag
+-------------------------------------------------
+
+to show its contents. NOTE! Trees have binary content, and as a result
+there is a special helper for showing that content, called
+`git-ls-tree`, which turns the binary content into a more easily
+readable form.
+
+It's especially instructive to look at "commit" objects, since those
+tend to be small and fairly self-explanatory. In particular, if you
+follow the convention of having the top commit name in `.git/HEAD`,
+you can do
+
+-------------------------------------------------
+$ git-cat-file commit HEAD
+-------------------------------------------------
+
+to see what the top commit was.
+
+Merging multiple trees
+----------------------
+
+Git helps you do a three-way merge, which you can expand to n-way by
+repeating the merge procedure arbitrary times until you finally
+"commit" the state. The normal situation is that you'd only do one
+three-way merge (two parents), and commit it, but if you like to, you
+can do multiple parents in one go.
+
+To do a three-way merge, you need the two sets of "commit" objects
+that you want to merge, use those to find the closest common parent (a
+third "commit" object), and then use those commit objects to find the
+state of the directory ("tree" object) at these points.
+
+To get the "base" for the merge, you first look up the common parent
+of two commits with
+
+-------------------------------------------------
+$ git-merge-base
+-------------------------------------------------
+
+which will return you the commit they are both based on. You should
+now look up the "tree" objects of those commits, which you can easily
+do with (for example)
+
+-------------------------------------------------
+$ git-cat-file commit | head -1
+-------------------------------------------------
+
+since the tree object information is always the first line in a commit
+object.
+
+Once you know the three trees you are going to merge (the one "original"
+tree, aka the common case, and the two "result" trees, aka the branches
+you want to merge), you do a "merge" read into the index. This will
+complain if it has to throw away your old index contents, so you should
+make sure that you've committed those - in fact you would normally
+always do a merge against your last commit (which should thus match what
+you have in your current index anyway).
+
+To do the merge, do
+
+-------------------------------------------------
+$ git-read-tree -m -u
+-------------------------------------------------
+
+which will do all trivial merge operations for you directly in the
+index file, and you can just write the result out with
+`git-write-tree`.
+
+
+Merging multiple trees, continued
+---------------------------------
+
+Sadly, many merges aren't trivial. If there are files that have
+been added.moved or removed, or if both branches have modified the
+same file, you will be left with an index tree that contains "merge
+entries" in it. Such an index tree can 'NOT' be written out to a tree
+object, and you will have to resolve any such merge clashes using
+other tools before you can write out the result.
+
+You can examine such index state with `git-ls-files --unmerged`
+command. An example:
+
+------------------------------------------------
+$ git-read-tree -m $orig HEAD $target
+$ git-ls-files --unmerged
+100644 263414f423d0e4d70dae8fe53fa34614ff3e2860 1 hello.c
+100644 06fa6a24256dc7e560efa5687fa84b51f0263c3a 2 hello.c
+100644 cc44c73eb783565da5831b4d820c962954019b69 3 hello.c
+------------------------------------------------
+
+Each line of the `git-ls-files --unmerged` output begins with
+the blob mode bits, blob SHA1, 'stage number', and the
+filename. The 'stage number' is git's way to say which tree it
+came from: stage 1 corresponds to `$orig` tree, stage 2 `HEAD`
+tree, and stage3 `$target` tree.
+
+Earlier we said that trivial merges are done inside
+`git-read-tree -m`. For example, if the file did not change
+from `$orig` to `HEAD` nor `$target`, or if the file changed
+from `$orig` to `HEAD` and `$orig` to `$target` the same way,
+obviously the final outcome is what is in `HEAD`. What the
+above example shows is that file `hello.c` was changed from
+`$orig` to `HEAD` and `$orig` to `$target` in a different way.
+You could resolve this by running your favorite 3-way merge
+program, e.g. `diff3` or `merge`, on the blob objects from
+these three stages yourself, like this:
+
+------------------------------------------------
+$ git-cat-file blob 263414f... >hello.c~1
+$ git-cat-file blob 06fa6a2... >hello.c~2
+$ git-cat-file blob cc44c73... >hello.c~3
+$ merge hello.c~2 hello.c~1 hello.c~3
+------------------------------------------------
+
+This would leave the merge result in `hello.c~2` file, along
+with conflict markers if there are conflicts. After verifying
+the merge result makes sense, you can tell git what the final
+merge result for this file is by:
+
+-------------------------------------------------
+$ mv -f hello.c~2 hello.c
+$ git-update-index hello.c
+-------------------------------------------------
+
+When a path is in unmerged state, running `git-update-index` for
+that path tells git to mark the path resolved.
+
+The above is the description of a git merge at the lowest level,
+to help you understand what conceptually happens under the hood.
+In practice, nobody, not even git itself, uses three `git-cat-file`
+for this. There is `git-merge-index` program that extracts the
+stages to temporary files and calls a "merge" script on it:
+
+-------------------------------------------------
+$ git-merge-index git-merge-one-file hello.c
+-------------------------------------------------
+
+and that is what higher level `git resolve` is implemented with.
+
+How git stores objects efficiently: pack files
+----------------------------------------------
+
+We've seen how git stores each object in a file named after the
+object's SHA1 hash.
+
+Unfortunately this system becomes inefficient once a project has a
+lot of objects. Try this on an old project:
+
+------------------------------------------------
+$ git count-objects
+6930 objects, 47620 kilobytes
+------------------------------------------------
+
+The first number is the number of objects which are kept in
+individual files. The second is the amount of space taken up by
+those "loose" objects.
+
+You can save space and make git faster by moving these loose objects in
+to a "pack file", which stores a group of objects in an efficient
+compressed format; the details of how pack files are formatted can be
+found in link:technical/pack-format.txt[technical/pack-format.txt].
+
+To put the loose objects into a pack, just run git repack:
+
+------------------------------------------------
+$ git repack
+Generating pack...
+Done counting 6020 objects.
+Deltifying 6020 objects.
+ 100% (6020/6020) done
+Writing 6020 objects.
+ 100% (6020/6020) done
+Total 6020, written 6020 (delta 4070), reused 0 (delta 0)
+Pack pack-3e54ad29d5b2e05838c75df582c65257b8d08e1c created.
+------------------------------------------------
+
+You can then run
+
+------------------------------------------------
+$ git prune
+------------------------------------------------
+
+to remove any of the "loose" objects that are now contained in the
+pack. This will also remove any unreferenced objects (which may be
+created when, for example, you use "git reset" to remove a commit).
+You can verify that the loose objects are gone by looking at the
+.git/objects directory or by running
+
+------------------------------------------------
+$ git count-objects
+0 objects, 0 kilobytes
+------------------------------------------------
+
+Although the object files are gone, any commands that refer to those
+objects will work exactly as they did before.
+
+The gitlink:git-gc[1] command performs packing, pruning, and more for
+you, so is normally the only high-level command you need.
+
+[[dangling-objects]]
+Dangling objects
+----------------
+
+The gitlink:git-fsck[1] command will sometimes complain about dangling
+objects. They are not a problem.
+
+The most common cause of dangling objects is that you've rebased a
+branch, or you have pulled from somebody else who rebased a branch--see
+<>. In that case, the old head of the original
+branch still exists, as does obviously everything it pointed to. The
+branch pointer itself just doesn't, since you replaced it with another
+one.
+
+There are also other situations too that cause dangling objects. For
+example, a "dangling blob" may arise because you did a "git add" of a
+file, but then, before you actually committed it and made it part of the
+bigger picture, you changed something else in that file and committed
+that *updated* thing - the old state that you added originally ends up
+not being pointed to by any commit or tree, so it's now a dangling blob
+object.
+
+Similarly, when the "recursive" merge strategy runs, and finds that
+there are criss-cross merges and thus more than one merge base (which is
+fairly unusual, but it does happen), it will generate one temporary
+midway tree (or possibly even more, if you had lots of criss-crossing
+merges and more than two merge bases) as a temporary internal merge
+base, and again, those are real objects, but the end result will not end
+up pointing to them, so they end up "dangling" in your repository.
+
+Generally, dangling objects aren't anything to worry about. They can
+even be very useful: if you screw something up, the dangling objects can
+be how you recover your old tree (say, you did a rebase, and realized
+that you really didn't want to - you can look at what dangling objects
+you have, and decide to reset your head to some old dangling state).
+
+For commits, the most useful thing to do with dangling objects tends to
+be to do a simple
+
+------------------------------------------------
+$ gitk --not --all
+------------------------------------------------
+
+For blobs and trees, you can't do the same, but you can examine them.
+You can just do
+
+------------------------------------------------
+$ git show
+------------------------------------------------
+
+to show what the contents of the blob were (or, for a tree, basically
+what the "ls" for that directory was), and that may give you some idea
+of what the operation was that left that dangling object.
+
+Usually, dangling blobs and trees aren't very interesting. They're
+almost always the result of either being a half-way mergebase (the blob
+will often even have the conflict markers from a merge in it, if you
+have had conflicting merges that you fixed up by hand), or simply
+because you interrupted a "git fetch" with ^C or something like that,
+leaving _some_ of the new objects in the object database, but just
+dangling and useless.
+
+Anyway, once you are sure that you're not interested in any dangling
+state, you can just prune all unreachable objects:
+
+------------------------------------------------
+$ git prune
+------------------------------------------------
+
+and they'll be gone. But you should only run "git prune" on a quiescent
+repository - it's kind of like doing a filesystem fsck recovery: you
+don't want to do that while the filesystem is mounted.
+
+(The same is true of "git-fsck" itself, btw - but since
+git-fsck never actually *changes* the repository, it just reports
+on what it found, git-fsck itself is never "dangerous" to run.
+Running it while somebody is actually changing the repository can cause
+confusing and scary messages, but it won't actually do anything bad. In
+contrast, running "git prune" while somebody is actively changing the
+repository is a *BAD* idea).
+
+Glossary of git terms
+=====================
+
+include::glossary.txt[]
+
+Notes and todo list for this manual
+===================================
+
+This is a work in progress.
+
+The basic requirements:
+ - It must be readable in order, from beginning to end, by
+ someone intelligent with a basic grasp of the unix
+ commandline, but without any special knowledge of git. If
+ necessary, any other prerequisites should be specifically
+ mentioned as they arise.
+ - Whenever possible, section headings should clearly describe
+ the task they explain how to do, in language that requires
+ no more knowledge than necessary: for example, "importing
+ patches into a project" rather than "the git-am command"
+
+Think about how to create a clear chapter dependency graph that will
+allow people to get to important topics without necessarily reading
+everything in between.
+
+Scan Documentation/ for other stuff left out; in particular:
+ howto's
+ some of technical/?
+ hooks
+ list of commands in gitlink:git[1]
+
+Scan email archives for other stuff left out
+
+Scan man pages to see if any assume more background than this manual
+provides.
+
+Simplify beginning by suggesting disconnected head instead of
+temporary branch creation?
+
+Explain how to refer to file stages in the "how to resolve a merge"
+section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The
+"git ls-files --unmerged --stage" thing is sorta useful too,
+actually. And note gitk --merge.
+
+Add more good examples. Entire sections of just cookbook examples
+might be a good idea; maybe make an "advanced examples" section a
+standard end-of-chapter section?
+
+Include cross-references to the glossary, where appropriate.
+
+Document shallow clones? See draft 1.5.0 release notes for some
+documentation.
+
+Add a sectin on working with other version control systems, including
+CVS, Subversion, and just imports of series of release tarballs.
+
+More details on gitweb?
+
+Write a chapter on using plumbing and writing scripts.