See also <<git-quick-start>> for a brief overview of git commands,
without any explanation.
-Also, see <<todo>> for ways that you can help make this manual more
+Finally, see <<todo>> for ways that you can help make this manual more
complete.
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:
+The best way to get one is by using the gitlink:git-clone[1] command to
+download a copy of an existing repository. If you don't already have a
+project in mind, here are some interesting examples:
------------------------------------------------
# git itself (approx. 10MB download):
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]]
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.
+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 of the project's contents. In git each such
+version is called a <<def_commit,commit>>.
A single git repository may contain multiple branches. It keeps track
of them by keeping a list of <<def_head,heads>> which reference the
-latest version on each branch; the gitlink:git-branch[1] command shows
+latest commit on each branch; the gitlink:git-branch[1] command shows
you the list of branch heads:
------------------------------------------------
------------------------------------------------
$ git show
-commit 2b5f6dcce5bf94b9b119e9ed8d537098ec61c3d2
-Author: Jamal Hadi Salim <hadi@cyberus.ca>
-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 <hadi@cyberus.ca>
- Signed-off-by: David S. Miller <davem@davemloft.net>
-
-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:
+commit 17cf781661e6d38f737f15f53ab552f1e95960d7
+Author: Linus Torvalds <torvalds@ppc970.osdl.org.(none)>
+Date: Tue Apr 19 14:11:06 2005 -0700
+
+ Remove duplicate getenv(DB_ENVIRONMENT) call
+
+ Noted by Tony Luck.
+
+diff --git a/init-db.c b/init-db.c
+index 65898fa..b002dc6 100644
+--- a/init-db.c
++++ b/init-db.c
+@@ -7,7 +7,7 @@
- struct xfrm_aevent_id {
- struct xfrm_usersa_id sa_id;
-+ xfrm_address_t saddr;
- __u32 flags;
-+ __u32 reqid;
- };
-...
+ int main(int argc, char **argv)
+ {
+- char *sha1_dir = getenv(DB_ENVIRONMENT), *path;
++ char *sha1_dir, *path;
+ int len, i;
+
+ if (mkdir(".git", 0755) < 0) {
------------------------------------------------
As you can see, a commit shows who made the latest change, what they
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.
+[[showing-commits-unique-to-a-branch]]
+Showing commits unique to a given branch
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Suppose you would like to see all the commits reachable from the branch
+head named "master" but not from any other head in your repository.
+
+We can list all the heads in this repository with
+gitlink:git-show-ref[1]:
+
+-------------------------------------------------
+$ git show-ref --heads
+bf62196b5e363d73353a9dcf094c59595f3153b7 refs/heads/core-tutorial
+db768d5504c1bb46f63ee9d6e1772bd047e05bf9 refs/heads/maint
+a07157ac624b2524a059a3414e99f6f44bebc1e7 refs/heads/master
+24dbc180ea14dc1aebe09f14c8ecf32010690627 refs/heads/tutorial-2
+1e87486ae06626c2f31eaa63d26fc0fd646c8af2 refs/heads/tutorial-fixes
+-------------------------------------------------
+
+We can get just the branch-head names, and remove "master", with
+the help of the standard utilities cut and grep:
+
+-------------------------------------------------
+$ git show-ref --heads | cut -d' ' -f2 | grep -v '^refs/heads/master'
+refs/heads/core-tutorial
+refs/heads/maint
+refs/heads/tutorial-2
+refs/heads/tutorial-fixes
+-------------------------------------------------
+
+And then we can ask to see all the commits reachable from master
+but not from these other heads:
+
+-------------------------------------------------
+$ gitk master --not $( git show-ref --heads | cut -d' ' -f2 |
+ grep -v '^refs/heads/master' )
+-------------------------------------------------
+
+Obviously, endless variations are possible; for example, to see all
+commits reachable from some head but not from any tag in the repository:
+
+-------------------------------------------------
+$ gitk $( git show-ref --heads ) --not $( git show-ref --tags )
+-------------------------------------------------
+
+(See gitlink:git-rev-parse[1] for explanations of commit-selecting
+syntax such as `--not`.)
+
[[making-a-release]]
Creating a changelog and tarball for a software release
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-------------------------------------------------
will use HEAD to produce a tar archive in which each filename is
-preceded by "prefix/".
+preceded by "project/".
If you're releasing a new version of a software project, you may want
to simultaneously make a changelog to include in the release
and then he just cut-and-pastes the output commands after verifying that
they look OK.
+[[Finding-comments-with-given-content]]
+Finding commits referencing a file with given content
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Somebody hands you a copy of a file, and asks which commits modified a
+file such that it contained the given content either before or after the
+commit. You can find out with this:
+
+-------------------------------------------------
+$ git log --raw -r --abbrev=40 --pretty=oneline -- filename |
+ grep -B 1 `git hash-object filename`
+-------------------------------------------------
+
+Figuring out why this works is left as an exercise to the (advanced)
+student. The gitlink:git-log[1], gitlink:git-diff-tree[1], and
+gitlink:git-hash-object[1] man pages may prove helpful.
+
[[Developing-with-git]]
Developing with git
===================
the first line on the Subject line and the rest of the commit in the
body.
+[[ignoring-files]]
+Ignoring files
+--------------
+
+A project will often generate files that you do 'not' want to track with git.
+This typically includes files generated by a build process or temporary
+backup files made by your editor. Of course, 'not' tracking files with git
+is just a matter of 'not' calling "`git add`" on them. But it quickly becomes
+annoying to have these untracked files lying around; e.g. they make
+"`git add .`" and "`git commit -a`" practically useless, and they keep
+showing up in the output of "`git status`".
+
+You can tell git to ignore certain files by creating a file called .gitignore
+in the top level of your working directory, with contents such as:
+
+-------------------------------------------------
+# Lines starting with '#' are considered comments.
+# Ignore any file named foo.txt.
+foo.txt
+# Ignore (generated) html files,
+*.html
+# except foo.html which is maintained by hand.
+!foo.html
+# Ignore objects and archives.
+*.[oa]
+-------------------------------------------------
+
+See gitlink:gitignore[5] for a detailed explanation of the syntax. You can
+also place .gitignore files in other directories in your working tree, and they
+will apply to those directories and their subdirectories. The `.gitignore`
+files can be added to your repository like any other files (just run `git add
+.gitignore` and `git commit`, as usual), which is convenient when the exclude
+patterns (such as patterns matching build output files) would also make sense
+for other users who clone your repository.
+
+If you wish the exclude patterns to affect only certain repositories
+(instead of every repository for a given project), you may instead put
+them in a file in your repository named .git/info/exclude, or in any file
+specified by the `core.excludesfile` configuration variable. Some git
+commands can also take exclude patterns directly on the command line.
+See gitlink:gitignore[5] for the details.
+
[[how-to-merge]]
How to merge
------------
-------------------------------------------------
Dangling objects are not a problem. At worst they may take up a little
-extra disk space. They can sometimes provide a last-resort method of
-recovery lost work--see <<dangling-objects>> for details. However, if
-you want, you may remove them with gitlink:git-prune[1] or the --prune
+extra disk space. They can sometimes provide a last-resort method for
+recovering lost work--see <<dangling-objects>> for details. However, if
+you wish, you can remove them with gitlink:git-prune[1] or the --prune
option to gitlink:git-gc[1]:
-------------------------------------------------
that a branch is created:
-------------------------------------------------
-$ git checkout --track -b origin/maint maint
+$ git checkout --track -b maint origin/maint
-------------------------------------------------
In addition to saving you keystrokes, "git pull" also helps you by
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
-------------------------------
+[[public-repositories]]
+Public git repositories
+-----------------------
-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 "<<getting-updates-with-git-pull, Getting
-updates with git pull>>".
+Another way to submit changes to a project is to tell the maintainer
+of that project to pull the changes from your repository using
+gitlink:git-pull[1]. In the section "<<getting-updates-with-git-pull,
+Getting updates with git pull>>" we described this as a way to get
+updates from the "main" repository, but it works just as well in the
+other direction.
-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 commands (gitlink:git-clone[1],
-git-fetch[1], git-pull[1], etc.) that accept a URL as an argument
-will also accept a local directory name; so, for example, you can
-use
+If you and the maintainer both have accounts on the same machine, then
+you can just pull changes from each other's repositories directly;
+commands that accept repository URLs as arguments will also accept a
+local directory name:
-------------------------------------------------
$ 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.
+or an ssh url:
+
+-------------------------------------------------
+$ git clone ssh://yourhost/~you/repository
+-------------------------------------------------
+
+For projects with few developers, or for synchronizing a few private
+repositories, this may be all you need.
+
+However, the more common way to do this is to maintain a separate public
+repository (usually on a different host) for others to pull changes
+from. This is usually more convenient, and 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
| 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:
+We explain how to do this in the following sections.
+
+[[setting-up-a-public-repository]]
+Setting up a public repository
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Assume your personal repository is in the directory ~/proj. We
+first create a new clone of the repository and tell git-daemon that it
+is meant to be public:
-------------------------------------------------
$ git clone --bare ~/proj proj.git
+$ touch proj.git/git-daemon-export-ok
-------------------------------------------------
The resulting directory proj.git contains a "bare" git repository--it is
-just the contents of the ".git" directory, without a checked-out copy of
-a working directory.
+just the contents of the ".git" directory, without any files checked out
+around it.
Next, copy proj.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
+[[exporting-via-git]]
+Exporting a git repository via the git protocol
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This is the preferred method.
+
+If someone else administers the server, they should tell you what
+directory to put the repository in, and what git:// url it will appear
+at. You can then skip to the section
"<<pushing-changes-to-a-public-repository,Pushing changes to a public
repository>>", below.
-Otherwise, the following sections explain how to export your newly
-created public repository:
+Otherwise, all you need to do is start gitlink:git-daemon[1]; it will
+listen on port 9418. By default, it will allow access to any directory
+that looks like a git directory and contains the magic file
+git-daemon-export-ok. Passing some directory paths as git-daemon
+arguments will further restrict the exports to those paths.
+
+You can also run git-daemon as an inetd service; see the
+gitlink:git-daemon[1] man page for details. (See especially the
+examples section.)
[[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.
(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].)
+link:hooks.html[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:
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
+Note that the two techniques outlined above (exporting via
<<exporting-via-http,http>> or <<exporting-via-git,git>>) 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
$ git push ssh://yourserver.com/~you/proj.git +master
-------------------------------------------------
+Note that the target of a "push" is normally a
+<<def_bare_repository,bare>> repository. You can also push to a
+repository that has a checked-out working tree, but the working tree
+will not be updated by the push. This may lead to unexpected results if
+the branch you push to is the currently checked-out branch!
+
As with git-fetch, you may also set up configuration options to
save typing; so, for example, after
[[setting-up-a-shared-repository]]
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
+link:cvs-migration.html[git for CVS users] for instructions on how to
set this up.
+However, while there is nothing wrong with git's support for shared
+repositories, this mode of operation is not generally recommended,
+simply because the mode of collaboration that git supports--by
+exchanging patches and pulling from public repositories--has so many
+advantages over the central shared repository:
+
+ - Git's ability to quickly import and merge patches allows a
+ single maintainer to process incoming changes even at very
+ high rates. And when that becomes too much, git-pull provides
+ an easy way for that maintainer to delegate this job to other
+ maintainers while still allowing optional review of incoming
+ changes.
+ - Since every developer's repository has the same complete copy
+ of the project history, no repository is special, and it is
+ trivial for another developer to take over maintenance of a
+ project, either by mutual agreement, or because a maintainer
+ becomes unresponsive or difficult to work with.
+ - The lack of a central group of "committers" means there is
+ less need for formal decisions about who is "in" and who is
+ "out".
+
[[setting-up-gitweb]]
-Allow web browsing of a repository
-----------------------------------
+Allowing 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
Linus's tree will be stored in the remote branch named origin/master,
and can be updated using gitlink:git-fetch[1]; you can track other
public trees using gitlink:git-remote[1] to set up a "remote" and
-git-fetch[1] to keep them up-to-date; see <<repositories-and-branches>>.
+gitlink:git-fetch[1] to keep them up-to-date; see
+<<repositories-and-branches>>.
Now create the branches in which you are going to work; these start out
at the current tip of origin/master branch, and should be set up (using
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 <ascii type without space>
+ <space> + <ascii decimal
-size> + <byte\0> + <binary object data>.
+forms a sequence of <ascii type without space>
{plus} <space> {plus} <ascii decimal
+size> {plus} <byte\0> {plus} <binary object data>.
The structured objects can further have their structure and
connectivity to other objects verified. This is generally done with
include::glossary.txt[]
[[git-quick-start]]
-Appendix A: Git Quick Start
-===========================
+Appendix A: Git Quick Reference
+===============================
-This is a quick summary of the major commands; the following chapters
-will explain how these work in more detail.
+This is a quick summary of the major commands; the previous chapters
+explain how these work in more detail.
[[quick-creating-a-new-repository]]
Creating a new repository
allow people to get to important topics without necessarily reading
everything in between.
-Say something about .gitignore.
-
Scan Documentation/ for other stuff left out; in particular:
howto's
some of technical/?
More details on gitweb?
Write a chapter on using plumbing and writing scripts.
+
+Alternates, clone -reference, etc.
+
+git unpack-objects -r for recovery
projects / git.git / blobdiff