Documentation: begin discussion of git-remote in user manual
[git/git.git] / Documentation / user-manual.txt
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1Git User's Manual
2_________________
3
4This manual is designed to be readable by someone with basic unix
5commandline skills, but no previous knowledge of git.
6
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7Chapters 1 and 2 explain how to fetch and study a project using
8git--the tools you'd need to build and test a particular version of a
9software project, to search for regressions, and so on.
6bd9b682 10
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11Chapter 3 explains how to do development with git, and chapter 4 how
12to share that development with others.
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13
14Further chapters cover more specialized topics.
15
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16Comprehensive reference documentation is available through the man
17pages. For a command such as "git clone", just use
18
19------------------------------------------------
20$ man git-clone
21------------------------------------------------
22
23Repositories and Branches
24=========================
25
26How to get a git repository
27---------------------------
28
29It will be useful to have a git repository to experiment with as you
30read this manual.
31
32The best way to get one is by using the gitlink:git-clone[1] command
33to download a copy of an existing repository for a project that you
34are interested in. If you don't already have a project in mind, here
35are some interesting examples:
36
37------------------------------------------------
38 # git itself (approx. 10MB download):
39$ git clone git://git.kernel.org/pub/scm/git/git.git
40 # the linux kernel (approx. 150MB download):
41$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
42------------------------------------------------
43
44The initial clone may be time-consuming for a large project, but you
45will only need to clone once.
46
47The clone command creates a new directory named after the project
48("git" or "linux-2.6" in the examples above). After you cd into this
49directory, you will see that it contains a copy of the project files,
50together with a special top-level directory named ".git", which
51contains all the information about the history of the project.
52
d5cd5de4 53In most of the following, examples will be taken from one of the two
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54repositories above.
55
56How to check out a different version of a project
57-------------------------------------------------
58
59Git is best thought of as a tool for storing the history of a
60collection of files. It stores the history as a compressed
61collection of interrelated snapshots (versions) of the project's
62contents.
63
64A single git repository may contain multiple branches. Each branch
65is a bookmark referencing a particular point in the project history.
66The gitlink:git-branch[1] command shows you the list of branches:
67
68------------------------------------------------
69$ git branch
70* master
71------------------------------------------------
72
73A freshly cloned repository contains a single branch, named "master",
74and the working directory contains the version of the project
75referred to by the master branch.
76
77Most projects also use tags. Tags, like branches, are references
78into the project's history, and can be listed using the
79gitlink:git-tag[1] command:
80
81------------------------------------------------
82$ git tag -l
83v2.6.11
84v2.6.11-tree
85v2.6.12
86v2.6.12-rc2
87v2.6.12-rc3
88v2.6.12-rc4
89v2.6.12-rc5
90v2.6.12-rc6
91v2.6.13
92...
93------------------------------------------------
94
95Create a new branch pointing to one of these versions and check it
96out using gitlink:git-checkout[1]:
97
98------------------------------------------------
99$ git checkout -b new v2.6.13
100------------------------------------------------
101
102The working directory then reflects the contents that the project had
103when it was tagged v2.6.13, and gitlink:git-branch[1] shows two
104branches, with an asterisk marking the currently checked-out branch:
105
106------------------------------------------------
107$ git branch
108 master
109* new
110------------------------------------------------
111
112If you decide that you'd rather see version 2.6.17, you can modify
113the current branch to point at v2.6.17 instead, with
114
115------------------------------------------------
116$ git reset --hard v2.6.17
117------------------------------------------------
118
119Note that if the current branch was your only reference to a
120particular point in history, then resetting that branch may leave you
121with no way to find the history it used to point to; so use this
122command carefully.
123
124Understanding History: Commits
125------------------------------
126
127Every change in the history of a project is represented by a commit.
128The gitlink:git-show[1] command shows the most recent commit on the
129current branch:
130
131------------------------------------------------
132$ git show
133commit 2b5f6dcce5bf94b9b119e9ed8d537098ec61c3d2
134Author: Jamal Hadi Salim <hadi@cyberus.ca>
135Date: Sat Dec 2 22:22:25 2006 -0800
136
137 [XFRM]: Fix aevent structuring to be more complete.
138
139 aevents can not uniquely identify an SA. We break the ABI with this
140 patch, but consensus is that since it is not yet utilized by any
141 (known) application then it is fine (better do it now than later).
142
143 Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
144 Signed-off-by: David S. Miller <davem@davemloft.net>
145
146diff --git a/Documentation/networking/xfrm_sync.txt b/Documentation/networking/xfrm_sync.txt
147index 8be626f..d7aac9d 100644
148--- a/Documentation/networking/xfrm_sync.txt
149+++ b/Documentation/networking/xfrm_sync.txt
150@@ -47,10 +47,13 @@ aevent_id structure looks like:
151
152 struct xfrm_aevent_id {
153 struct xfrm_usersa_id sa_id;
154+ xfrm_address_t saddr;
155 __u32 flags;
156+ __u32 reqid;
157 };
158...
159------------------------------------------------
160
161As you can see, a commit shows who made the latest change, what they
162did, and why.
163
164Every commit has a 20-digit id, sometimes called the "SHA1 id", shown
165on the first line of the "git show" output. You can usually refer to
166a commit by a shorter name, such as a tag or a branch name, but this
167longer id can also be useful. In particular, it is a globally unique
168name for this commit: so if you tell somebody else the SHA1 id (for
169example in email), then you are guaranteed they will see the same
170commit in their repository that you do in yours.
171
172Understanding history: commits, parents, and reachability
173~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
174
175Every commit (except the very first commit in a project) also has a
176parent commit which shows what happened before this commit.
177Following the chain of parents will eventually take you back to the
178beginning of the project.
179
180However, the commits do not form a simple list; git allows lines of
181development to diverge and then reconverge, and the point where two
182lines of development reconverge is called a "merge". The commit
183representing a merge can therefore have more than one parent, with
184each parent representing the most recent commit on one of the lines
185of development leading to that point.
186
187The best way to see how this works is using the gitlink:gitk[1]
188command; running gitk now on a git repository and looking for merge
189commits will help understand how the git organizes history.
190
191In the following, we say that commit X is "reachable" from commit Y
192if commit X is an ancestor of commit Y. Equivalently, you could say
193that Y is a descendent of X, or that there is a chain of parents
194leading from commit Y to commit X.
195
196Undestanding history: History diagrams
197~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
198
199We will sometimes represent git history using diagrams like the one
200below. Commits are shown as "o", and the links between them with
201lines drawn with - / and \. Time goes left to right:
202
203 o--o--o <-- Branch A
204 /
205 o--o--o <-- master
206 \
207 o--o--o <-- Branch B
208
209If we need to talk about a particular commit, the character "o" may
210be replaced with another letter or number.
211
212Understanding history: What is a branch?
213~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
214
215Though we've been using the word "branch" to mean a kind of reference
216to a particular commit, the word branch is also commonly used to
217refer to the line of commits leading up to that point. In the
218example above, git may think of the branch named "A" as just a
219pointer to one particular commit, but we may refer informally to the
220line of three commits leading up to that point as all being part of
221"branch A".
222
223If we need to make it clear that we're just talking about the most
224recent commit on the branch, we may refer to that commit as the
225"head" of the branch.
226
227Manipulating branches
228---------------------
229
230Creating, deleting, and modifying branches is quick and easy; here's
231a summary of the commands:
232
233git branch::
234 list all branches
235git branch <branch>::
236 create a new branch named <branch>, referencing the same
237 point in history as the current branch
238git branch <branch> <start-point>::
239 create a new branch named <branch>, referencing
240 <start-point>, which may be specified any way you like,
241 including using a branch name or a tag name
242git branch -d <branch>::
243 delete the branch <branch>; if the branch you are deleting
244 points to a commit which is not reachable from this branch,
245 this command will fail with a warning.
246git branch -D <branch>::
247 even if the branch points to a commit not reachable
248 from the current branch, you may know that that commit
249 is still reachable from some other branch or tag. In that
250 case it is safe to use this command to force git to delete
251 the branch.
252git checkout <branch>::
253 make the current branch <branch>, updating the working
254 directory to reflect the version referenced by <branch>
255git checkout -b <new> <start-point>::
256 create a new branch <new> referencing <start-point>, and
257 check it out.
258
259It is also useful to know that the special symbol "HEAD" can always
260be used to refer to the current branch.
261
262Examining branches from a remote repository
263-------------------------------------------
264
265The "master" branch that was created at the time you cloned is a copy
266of the HEAD in the repository that you cloned from. That repository
267may also have had other branches, though, and your local repository
268keeps branches which track each of those remote branches, which you
269can view using the "-r" option to gitlink:git-branch[1]:
270
271------------------------------------------------
272$ git branch -r
273 origin/HEAD
274 origin/html
275 origin/maint
276 origin/man
277 origin/master
278 origin/next
279 origin/pu
280 origin/todo
281------------------------------------------------
282
283You cannot check out these remote-tracking branches, but you can
284examine them on a branch of your own, just as you would a tag:
285
286------------------------------------------------
287$ git checkout -b my-todo-copy origin/todo
288------------------------------------------------
289
290Note that the name "origin" is just the name that git uses by default
291to refer to the repository that you cloned from.
292
293[[how-git-stores-references]]
294How git stores references
295-------------------------
296
297Branches, remote-tracking branches, and tags are all references to
298commits. Git stores these references in the ".git" directory. Most
299of them are stored in .git/refs/:
300
301 - branches are stored in .git/refs/heads
302 - tags are stored in .git/refs/tags
303 - remote-tracking branches for "origin" are stored in
304 .git/refs/remotes/origin/
305
306If you look at one of these files you will see that they usually
307contain just the SHA1 id of a commit:
308
309------------------------------------------------
310$ ls .git/refs/heads/
311master
312$ cat .git/refs/heads/master
313c0f982dcf188d55db9d932a39d4ea7becaa55fed
314------------------------------------------------
315
316You can refer to a reference by its path relative to the .git
317directory. However, we've seen above that git will also accept
318shorter names; for example, "master" is an acceptable shortcut for
319"refs/heads/master", and "origin/master" is a shortcut for
320"refs/remotes/origin/master".
321
322As another useful shortcut, you can also refer to the "HEAD" of
323"origin" (or any other remote), using just the name of the remote.
324
325For the complete list of paths which git checks for references, and
326how it decides which to choose when there are multiple references
327with the same name, see the "SPECIFYING REVISIONS" section of
328gitlink:git-rev-parse[1].
329
330[[Updating-a-repository-with-git-fetch]]
331Updating a repository with git fetch
332------------------------------------
333
334Eventually the developer cloned from will do additional work in her
335repository, creating new commits and advancing the branches to point
336at the new commits.
337
338The command "git fetch", with no arguments, will update all of the
339remote-tracking branches to the latest version found in her
340repository. It will not touch any of your own branches--not even the
341"master" branch that was created for you on clone.
342
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343Fetching branches from other repositories
344-----------------------------------------
345
346You can also track branches from repositories other than the one you
347cloned from, using gitlink:git-remote[1]:
348
349-------------------------------------------------
350$ git remote add linux-nfs git://linux-nfs.org/pub/nfs-2.6.git
351$ git fetch
352* refs/remotes/linux-nfs/master: storing branch 'master' ...
353 commit: bf81b46
354-------------------------------------------------
355
356New remote-tracking branches will be stored under the shorthand name
357that you gave "git remote add", in this case linux-nfs:
358
359-------------------------------------------------
360$ git branch -r
361linux-nfs/master
362origin/master
363-------------------------------------------------
364
365If you run "git fetch <remote>" later, the tracking branches for the
366named <remote> will be updated.
367
368If you examine the file .git/config, you will see that git has added
369a new stanza:
370
371-------------------------------------------------
372$ cat .git/config
373...
374[remote "linux-nfs"]
375 url = git://linux-nfs.org/~bfields/git.git
376 fetch = +refs/heads/*:refs/remotes/linux-nfs-read/*
377...
378-------------------------------------------------
379
380This is what causes git to track the remote's branches; you may
381modify or delete these configuration options by editing .git/config
382with a text editor.
383
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384Fetching individual branches
385----------------------------
386
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387TODO: find another home for this, later on:
388
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389You can also choose to update just one branch at a time:
390
391-------------------------------------------------
392$ git fetch origin todo:refs/remotes/origin/todo
393-------------------------------------------------
394
395The first argument, "origin", just tells git to fetch from the
396repository you originally cloned from. The second argument tells git
397to fetch the branch named "todo" from the remote repository, and to
398store it locally under the name refs/remotes/origin/todo; as we saw
399above, remote-tracking branches are stored under
400refs/remotes/<name-of-repository>/<name-of-branch>.
401
402You can also fetch branches from other repositories; so
403
404-------------------------------------------------
405$ git fetch git://example.com/proj.git master:refs/remotes/example/master
406-------------------------------------------------
407
408will create a new reference named "refs/remotes/example/master" and
409store in it the branch named "master" from the repository at the
410given URL. If you already have a branch named
411"refs/remotes/example/master", it will attempt to "fast-forward" to
412the commit given by example.com's master branch. So next we explain
413what a fast-forward is:
414
415[[fast-forwards]]
416Understanding git history: fast-forwards
417----------------------------------------
418
419In the previous example, when updating an existing branch, "git
420fetch" checks to make sure that the most recent commit on the remote
421branch is a descendant of the most recent commit on your copy of the
422branch before updating your copy of the branch to point at the new
423commit. Git calls this process a "fast forward".
424
425A fast forward looks something like this:
426
427 o--o--o--o <-- old head of the branch
428 \
429 o--o--o <-- new head of the branch
430
431
432In some cases it is possible that the new head will *not* actually be
433a descendant of the old head. For example, the developer may have
434realized she made a serious mistake, and decided to backtrack,
435resulting in a situation like:
436
437 o--o--o--o--a--b <-- old head of the branch
438 \
439 o--o--o <-- new head of the branch
440
441
442
443In this case, "git fetch" will fail, and print out a warning.
444
445In that case, you can still force git to update to the new head, as
446described in the following section. However, note that in the
447situation above this may mean losing the commits labeled "a" and "b",
448unless you've already created a reference of your own pointing to
449them.
450
451Forcing git fetch to do non-fast-forward updates
452------------------------------------------------
453
454If git fetch fails because the new head of a branch is not a
455descendant of the old head, you may force the update with:
456
457-------------------------------------------------
458$ git fetch git://example.com/proj.git +master:refs/remotes/example/master
459-------------------------------------------------
460
461Note the addition of the "+" sign. Be aware that commits which the
462old version of example/master pointed at may be lost, as we saw in
463the previous section.
464
465Configuring remote branches
466---------------------------
467
468We saw above that "origin" is just a shortcut to refer to the
469repository which you originally cloned from. This information is
470stored in git configuration variables, which you can see using
471gitlink:git-repo-config[1]:
472
473-------------------------------------------------
474$ git-repo-config -l
475core.repositoryformatversion=0
476core.filemode=true
477core.logallrefupdates=true
478remote.origin.url=git://git.kernel.org/pub/scm/git/git.git
479remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
480branch.master.remote=origin
481branch.master.merge=refs/heads/master
482-------------------------------------------------
483
484If there are other repositories that you also use frequently, you can
485create similar configuration options to save typing; for example,
486after
487
488-------------------------------------------------
489$ git repo-config remote.example.url=git://example.com/proj.git
490-------------------------------------------------
491
492then the following two commands will do the same thing:
493
494-------------------------------------------------
495$ git fetch git://example.com/proj.git master:refs/remotes/example/master
496$ git fetch example master:refs/remotes/example/master
497-------------------------------------------------
498
499Even better, if you add one more option:
500
501-------------------------------------------------
502$ git repo-config remote.example.fetch=master:refs/remotes/example/master
503-------------------------------------------------
504
505then the following commands will all do the same thing:
506
507-------------------------------------------------
508$ git fetch git://example.com/proj.git master:ref/remotes/example/master
509$ git fetch example master:ref/remotes/example/master
510$ git fetch example example/master
511$ git fetch example
512-------------------------------------------------
513
514You can also add a "+" to force the update each time:
515
516-------------------------------------------------
517$ git repo-config +master:ref/remotes/example/master
518-------------------------------------------------
519
520Don't do this unless you're sure you won't mind "git fetch" possibly
521throwing away commits on mybranch.
522
523Also note that all of the above configuration can be performed by
524directly editing the file .git/config instead of using
525gitlink:git-repo-config[1].
526
527See gitlink:git-repo-config[1] for more details on the configuration
528options mentioned above.
529
530Exploring git history
531=====================
532
533Git is best thought of as a tool for storing the history of a
534collection of files. It does this by storing compressed snapshots of
535the contents of a file heirarchy, together with "commits" which show
536the relationships between these snapshots.
537
538Git provides extremely flexible and fast tools for exploring the
539history of a project.
540
541We start with one specialized tool which is useful for finding the
542commit that introduced a bug into a project.
543
544How to use bisect to find a regression
545--------------------------------------
546
547Suppose version 2.6.18 of your project worked, but the version at
548"master" crashes. Sometimes the best way to find the cause of such a
549regression is to perform a brute-force search through the project's
550history to find the particular commit that caused the problem. The
551gitlink:git-bisect[1] command can help you do this:
552
553-------------------------------------------------
554$ git bisect start
555$ git bisect good v2.6.18
556$ git bisect bad master
557Bisecting: 3537 revisions left to test after this
558[65934a9a028b88e83e2b0f8b36618fe503349f8e] BLOCK: Make USB storage depend on SCSI rather than selecting it [try #6]
559-------------------------------------------------
560
561If you run "git branch" at this point, you'll see that git has
562temporarily moved you to a new branch named "bisect". This branch
563points to a commit (with commit id 65934...) that is reachable from
564v2.6.19 but not from v2.6.18. Compile and test it, and see whether
565it crashes. Assume it does crash. Then:
566
567-------------------------------------------------
568$ git bisect bad
569Bisecting: 1769 revisions left to test after this
570[7eff82c8b1511017ae605f0c99ac275a7e21b867] i2c-core: Drop useless bitmaskings
571-------------------------------------------------
572
573checks out an older version. Continue like this, telling git at each
574stage whether the version it gives you is good or bad, and notice
575that the number of revisions left to test is cut approximately in
576half each time.
577
578After about 13 tests (in this case), it will output the commit id of
579the guilty commit. You can then examine the commit with
580gitlink:git-show[1], find out who wrote it, and mail them your bug
581report with the commit id. Finally, run
582
583-------------------------------------------------
584$ git bisect reset
585-------------------------------------------------
586
587to return you to the branch you were on before and delete the
588temporary "bisect" branch.
589
590Note that the version which git-bisect checks out for you at each
591point is just a suggestion, and you're free to try a different
592version if you think it would be a good idea. For example,
593occasionally you may land on a commit that broke something unrelated;
594run
595
596-------------------------------------------------
597$ git bisect-visualize
598-------------------------------------------------
599
600which will run gitk and label the commit it chose with a marker that
601says "bisect". Chose a safe-looking commit nearby, note its commit
602id, and check it out with:
603
604-------------------------------------------------
605$ git reset --hard fb47ddb2db...
606-------------------------------------------------
607
608then test, run "bisect good" or "bisect bad" as appropriate, and
609continue.
610
611Naming commits
612--------------
613
614We have seen several ways of naming commits already:
615
616 - 20-digit SHA1 id
617 - branch name: refers to the commit at the head of the given
618 branch
619 - tag name: refers to the commit pointed to by the given tag
620 (we've seen branches and tags are special cases of
621 <<how-git-stores-references,references>>).
622 - HEAD: refers to the head of the current branch
623
624There are many more; see the "SPECIFYING REVISION" section of the
625gitlink:git-rev-list[1] man page for the complete list of ways to
626name revisions. Some examples:
627
628-------------------------------------------------
629$ git show fb47ddb2 # the first few characters of the SHA1 id
630 # are usually enough to specify it uniquely
631$ git show HEAD^ # the parent of the HEAD commit
632$ git show HEAD^^ # the grandparent
633$ git show HEAD~4 # the great-great-grandparent
634-------------------------------------------------
635
636Recall that merge commits may have more than one parent; by default,
637^ and ~ follow the first parent listed in the commit, but you can
638also choose:
639
640-------------------------------------------------
641$ git show HEAD^1 # show the first parent of HEAD
642$ git show HEAD^2 # show the second parent of HEAD
643-------------------------------------------------
644
645In addition to HEAD, there are several other special names for
646commits:
647
648Merges (to be discussed later), as well as operations such as
649git-reset, which change the currently checked-out commit, generally
650set ORIG_HEAD to the value HEAD had before the current operation.
651
652The git-fetch operation always stores the head of the last fetched
653branch in FETCH_HEAD. For example, if you run git fetch without
654specifying a local branch as the target of the operation
655
656-------------------------------------------------
657$ git fetch git://example.com/proj.git theirbranch
658-------------------------------------------------
659
660the fetched commits will still be available from FETCH_HEAD.
661
662When we discuss merges we'll also see the special name MERGE_HEAD,
663which refers to the other branch that we're merging in to the current
664branch.
665
666Creating tags
667-------------
668
669We can also create a tag to refer to a particular commit; after
670running
671
672-------------------------------------------------
673$ git-tag stable-1 1b2e1d63ff
674-------------------------------------------------
675
676You can use stable-1 to refer to the commit 1b2e1d63ff.
677
678This creates a "lightweight" tag. If the tag is a tag you wish to
679share with others, and possibly sign cryptographically, then you
680should create a tag object instead; see the gitlink:git-tag[1] man
681page for details.
682
683Browsing revisions
684------------------
685
686The gitlink:git-log[1] command can show lists of commits. On its
687own, it shows all commits reachable from the parent commit; but you
688can also make more specific requests:
689
690-------------------------------------------------
691$ git log v2.5.. # commits since (not reachable from) v2.5
692$ git log test..master # commits reachable from master but not test
693$ git log master..test # ...reachable from test but not master
694$ git log master...test # ...reachable from either test or master,
695 # but not both
696$ git log --since="2 weeks ago" # commits from the last 2 weeks
697$ git log Makefile # commits which modify Makefile
698$ git log fs/ # ... which modify any file under fs/
699$ git log -S'foo()' # commits which add or remove any file data
700 # matching the string 'foo()'
701-------------------------------------------------
702
703And of course you can combine all of these; the following finds
704commits since v2.5 which touch the Makefile or any file under fs:
705
706-------------------------------------------------
707$ git log v2.5.. Makefile fs/
708-------------------------------------------------
709
710You can also ask git log to show patches:
711
712-------------------------------------------------
713$ git log -p
714-------------------------------------------------
715
716See the "--pretty" option in the gitlink:git-log[1] man page for more
717display options.
718
719Note that git log starts with the most recent commit and works
720backwards through the parents; however, since git history can contain
721multiple independant lines of development, the particular order that
722commits are listed in may be somewhat arbitrary.
723
724Generating diffs
725----------------
726
727You can generate diffs between any two versions using
728gitlink:git-diff[1]:
729
730-------------------------------------------------
731$ git diff master..test
732-------------------------------------------------
733
734Sometimes what you want instead is a set of patches:
735
736-------------------------------------------------
737$ git format-patch master..test
738-------------------------------------------------
739
740will generate a file with a patch for each commit reachable from test
741but not from master. Note that if master also has commits which are
742not reachable from test, then the combined result of these patches
743will not be the same as the diff produced by the git-diff example.
744
745Viewing old file versions
746-------------------------
747
748You can always view an old version of a file by just checking out the
749correct revision first. But sometimes it is more convenient to be
750able to view an old version of a single file without checking
751anything out; this command does that:
752
753-------------------------------------------------
754$ git show v2.5:fs/locks.c
755-------------------------------------------------
756
757Before the colon may be anything that names a commit, and after it
758may be any path to a file tracked by git.
759
760Developing with git
761===================
762
763Telling git your name
764---------------------
765
766Before creating any commits, you should introduce yourself to git. The
767easiest way to do so is:
768
769------------------------------------------------
770$ cat >~/.gitconfig <<\EOF
771[user]
772 name = Your Name Comes Here
773 email = you@yourdomain.example.com
774EOF
775------------------------------------------------
776
777
778Creating a new repository
779-------------------------
780
781Creating a new repository from scratch is very easy:
782
783-------------------------------------------------
784$ mkdir project
785$ cd project
786$ git init-db
787-------------------------------------------------
788
789If you have some initial content (say, a tarball):
790
791-------------------------------------------------
792$ tar -xzvf project.tar.gz
793$ cd project
794$ git init-db
795$ git add . # include everything below ./ in the first commit:
796$ git commit
797-------------------------------------------------
798
799[[how-to-make-a-commit]]
800how to make a commit
801--------------------
802
803Creating a new commit takes three steps:
804
805 1. Making some changes to the working directory using your
806 favorite editor.
807 2. Telling git about your changes.
808 3. Creating the commit using the content you told git about
809 in step 2.
810
811In practice, you can interleave and repeat steps 1 and 2 as many
812times as you want: in order to keep track of what you want committed
813at step 3, git maintains a snapshot of the tree's contents in a
814special staging area called "the index."
815
816By default, the content of the index is identical to that of the
817HEAD. The command "git diff --cached" shows the difference between
818HEAD and the index, so you should no output from that command.
819
820Modifying the index is easy:
821
822To update the index with the new contents of a modified file, use
823
824-------------------------------------------------
825$ git add path/to/file
826-------------------------------------------------
827
828To add the contents of a new file to the index, use
829
830-------------------------------------------------
831$ git add path/to/file
832-------------------------------------------------
833
834To remove a file from the index that you've removed from the working
835tree,
836
837-------------------------------------------------
838$ git rm path/to/file
839-------------------------------------------------
840
841After each step you can verify that
842
843-------------------------------------------------
844$ git diff --cached
845-------------------------------------------------
846
847always shows the difference between the HEAD and the index file--this
848is what you'd commit if you created the commit now--and that
849
850-------------------------------------------------
851$ git diff
852-------------------------------------------------
853
854shows the difference between the working tree and the index file.
855
856Note that "git add" always adds just the current contents of a file
857to the index; further changes to the same file will be ignored unless
858you run git-add on the file again.
859
860When you're ready, just run
861
862-------------------------------------------------
863$ git commit
864-------------------------------------------------
865
866and git will prompt you for a commit message and then create the new
867commmit. Check to make sure it looks like what you expected with
868
869-------------------------------------------------
870$ git show
871-------------------------------------------------
872
873As a special shortcut,
874
875-------------------------------------------------
876$ git commit -a
877-------------------------------------------------
878
879will update the index with any files that you've modified or removed
880and create a commit, all in one step.
881
882A number of commands are useful for keeping track of what you're
883about to commit:
884
885-------------------------------------------------
886$ git diff --cached # difference between HEAD and the index; what
887 # would be commited if you ran "commit" now.
888$ git diff # difference between the index file and your
889 # working directory; changes that would not
890 # be included if you ran "commit" now.
891$ git status # a brief per-file summary of the above.
892-------------------------------------------------
893
894creating good commit messages
895-----------------------------
896
897Though not required, it's a good idea to begin the commit message
898with a single short (less than 50 character) line summarizing the
899change, followed by a blank line and then a more thorough
900description. Tools that turn commits into email, for example, use
901the first line on the Subject line and the rest of the commit in the
902body.
903
904how to merge
905------------
906
907You can rejoin two diverging branches of development using
908gitlink:git-merge[1]:
909
910-------------------------------------------------
911$ git merge branchname
912-------------------------------------------------
913
914merges the development in the branch "branchname" into the current
915branch. If there are conflicts--for example, if the same file is
916modified in two different ways in the remote branch and the local
917branch--then you are warned; the output may look something like this:
918
919-------------------------------------------------
920$ git pull . next
921Trying really trivial in-index merge...
922fatal: Merge requires file-level merging
923Nope.
924Merging HEAD with 77976da35a11db4580b80ae27e8d65caf5208086
925Merging:
92615e2162 world
92777976da goodbye
928found 1 common ancestor(s):
929d122ed4 initial
930Auto-merging file.txt
931CONFLICT (content): Merge conflict in file.txt
932Automatic merge failed; fix conflicts and then commit the result.
933-------------------------------------------------
934
935Conflict markers are left in the problematic files, and after
936you resolve the conflicts manually, you can update the index
937with the contents and run git commit, as you normally would when
938creating a new file.
939
940If you examine the resulting commit using gitk, you will see that it
941has two parents, one pointing to the top of the current branch, and
942one to the top of the other branch.
943
944In more detail:
945
946[[resolving-a-merge]]
947Resolving a merge
948-----------------
949
950When a merge isn't resolved automatically, git leaves the index and
951the working tree in a special state that gives you all the
952information you need to help resolve the merge.
953
954Files with conflicts are marked specially in the index, so until you
955resolve the problem and update the index, git commit will fail:
956
957-------------------------------------------------
958$ git commit
959file.txt: needs merge
960-------------------------------------------------
961
962Also, git status will list those files as "unmerged".
963
964All of the changes that git was able to merge automatically are
965already added to the index file, so gitlink:git-diff[1] shows only
966the conflicts. Also, it uses a somewhat unusual syntax:
967
968-------------------------------------------------
969$ git diff
970diff --cc file.txt
971index 802992c,2b60207..0000000
972--- a/file.txt
973+++ b/file.txt
974@@@ -1,1 -1,1 +1,5 @@@
975++<<<<<<< HEAD:file.txt
976 +Hello world
977++=======
978+ Goodbye
979++>>>>>>> 77976da35a11db4580b80ae27e8d65caf5208086:file.txt
980-------------------------------------------------
981
982Recall that the commit which will be commited after we resolve this
983conflict will have two parents instead of the usual one: one parent
984will be HEAD, the tip of the current branch; the other will be the
985tip of the other branch, which is stored temporarily in MERGE_HEAD.
986
987The diff above shows the differences between the working-tree version
988of file.txt and two previous version: one version from HEAD, and one
989from MERGE_HEAD. So instead of preceding each line by a single "+"
990or "-", it now uses two columns: the first column is used for
991differences between the first parent and the working directory copy,
992and the second for differences between the second parent and the
993working directory copy. Thus after resolving the conflict in the
994obvious way, the diff will look like:
995
996-------------------------------------------------
997$ git diff
998diff --cc file.txt
999index 802992c,2b60207..0000000
1000--- a/file.txt
1001+++ b/file.txt
1002@@@ -1,1 -1,1 +1,1 @@@
1003- Hello world
1004 -Goodbye
1005++Goodbye world
1006-------------------------------------------------
1007
1008This shows that our resolved version deleted "Hello world" from the
1009first parent, deleted "Goodbye" from the second parent, and added
1010"Goodbye world", which was previously absent from both.
1011
1012The gitlink:git-log[1] command also provides special help for merges:
1013
1014-------------------------------------------------
1015$ git log --merge
1016-------------------------------------------------
1017
1018This will list all commits which exist only on HEAD or on MERGE_HEAD,
1019and which touch an unmerged file.
1020
1021We can now add the resolved version to the index and commit:
1022
1023-------------------------------------------------
1024$ git add file.txt
1025$ git commit
1026-------------------------------------------------
1027
1028Note that the commit message will already be filled in for you with
1029some information about the merge. Normally you can just use this
1030default message unchanged, but you may add additional commentary of
1031your own if desired.
1032
1033[[undoing-a-merge]]
1034undoing a merge
1035---------------
1036
1037If you get stuck and decide to just give up and throw the whole mess
1038away, you can always return to the pre-merge state with
1039
1040-------------------------------------------------
1041$ git reset --hard HEAD
1042-------------------------------------------------
1043
1044Or, if you've already commited the merge that you want to throw away,
1045
1046-------------------------------------------------
1047$ git reset --hard HEAD^
1048-------------------------------------------------
1049
1050However, this last command can be dangerous in some cases--never
1051throw away a commit you have already committed if that commit may
1052itself have been merged into another branch, as doing so may confuse
1053further merges.
1054
1055Fast-forward merges
1056-------------------
1057
1058There is one special case not mentioned above, which is treated
1059differently. Normally, a merge results in a merge commit, with two
1060parents, one pointing at each of the two lines of development that
1061were merged.
1062
1063However, if one of the two lines of development is completely
1064contained within the other--so every commit present in the one is
1065already contained in the other--then git just performs a
1066<<fast-forwards,fast forward>>; the head of the current branch is
1067moved forward to point at the head of the merged-in branch, without
1068any new commits being created.
1069
b684f830
BF
1070Fixing mistakes
1071---------------
1072
1073If you've messed up the working tree, but haven't yet committed your
1074mistake, you can return the entire working tree to the last committed
1075state with
1076
1077-------------------------------------------------
1078$ git reset --hard HEAD
1079-------------------------------------------------
1080
1081If you make a commit that you later wish you hadn't, there are two
1082fundamentally different ways to fix the problem:
1083
1084 1. You can create a new commit that undoes whatever was done
1085 by the previous commit. This is the correct thing if your
1086 mistake has already been made public.
1087
1088 2. You can go back and modify the old commit. You should
1089 never do this if you have already made the history public;
1090 git does not normally expect the "history" of a project to
1091 change, and cannot correctly perform repeated merges from
1092 a branch that has had its history changed.
1093
1094Fixing a mistake with a new commit
1095~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1096
1097Creating a new commit that reverts an earlier change is very easy;
1098just pass the gitlink:git-revert[1] command a reference to the bad
1099commit; for example, to revert the most recent commit:
1100
1101-------------------------------------------------
1102$ git revert HEAD
1103-------------------------------------------------
1104
1105This will create a new commit which undoes the change in HEAD. You
1106will be given a chance to edit the commit message for the new commit.
1107
1108You can also revert an earlier change, for example, the next-to-last:
1109
1110-------------------------------------------------
1111$ git revert HEAD^
1112-------------------------------------------------
1113
1114In this case git will attempt to undo the old change while leaving
1115intact any changes made since then. If more recent changes overlap
1116with the changes to be reverted, then you will be asked to fix
1117conflicts manually, just as in the case of <<resolving-a-merge,
1118resolving a merge>>.
1119
1120Fixing a mistake by editing history
1121~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1122
1123If the problematic commit is the most recent commit, and you have not
1124yet made that commit public, then you may just
1125<<undoing-a-merge,destroy it using git-reset>>.
1126
1127Alternatively, you
1128can edit the working directory and update the index to fix your
1129mistake, just as if you were going to <<how-to-make-a-commit,create a
1130new commit>>, then run
1131
1132-------------------------------------------------
1133$ git commit --amend
1134-------------------------------------------------
1135
1136which will replace the old commit by a new commit incorporating your
1137changes, giving you a chance to edit the old commit message first.
1138
1139Again, you should never do this to a commit that may already have
1140been merged into another branch; use gitlink:git-revert[1] instead in
1141that case.
1142
1143It is also possible to edit commits further back in the history, but
1144this is an advanced topic to be left for
1145<<cleaning-up-history,another chapter>>.
1146
1147Checking out an old version of a file
1148~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1149
1150In the process of undoing a previous bad change, you may find it
1151useful to check out an older version of a particular file using
1152gitlink:git-checkout[1]. We've used git checkout before to switch
1153branches, but it has quite different behavior if it is given a path
1154name: the command
1155
1156-------------------------------------------------
1157$ git checkout HEAD^ path/to/file
1158-------------------------------------------------
1159
1160replaces path/to/file by the contents it had in the commit HEAD^, and
1161also updates the index to match. It does not change branches.
1162
1163If you just want to look at an old version of the file, without
1164modifying the working directory, you can do that with
1165gitlink:git-show[1]:
1166
1167-------------------------------------------------
1168$ git show HEAD^ path/to/file
1169-------------------------------------------------
1170
1171which will display the given version of the file.
1172
d19fbc3c
BF
1173Ensuring good performance
1174-------------------------
1175
1176On large repositories, git depends on compression to keep the history
1177information from taking up to much space on disk or in memory.
1178
1179This compression is not performed automatically. Therefore you
1180should occasionally run
1181
1182-------------------------------------------------
1183$ git gc
1184-------------------------------------------------
1185
1186to recompress the archive and to prune any commits which are no
1187longer referred to anywhere. This can be very time-consuming, and
1188you should not modify the repository while it is working, so you
1189should run it while you are not working.
1190
1191Sharing development with others
b684f830 1192===============================
d19fbc3c
BF
1193
1194[[getting-updates-with-git-pull]]
1195Getting updates with git pull
b684f830 1196-----------------------------
d19fbc3c
BF
1197
1198After you clone a repository and make a few changes of your own, you
1199may wish to check the original repository for updates and merge them
1200into your own work.
1201
1202We have already seen <<Updating-a-repository-with-git-fetch,how to
1203keep remote tracking branches up to date>> with gitlink:git-fetch[1],
1204and how to merge two branches. So you can merge in changes from the
1205original repository's master branch with:
1206
1207-------------------------------------------------
1208$ git fetch
1209$ git merge origin/master
1210-------------------------------------------------
1211
1212However, the gitlink:git-pull[1] command provides a way to do this in
1213one step:
1214
1215-------------------------------------------------
1216$ git pull origin master
1217-------------------------------------------------
1218
1219In fact, "origin" is normally the default repository to pull from,
1220and the default branch is normally the HEAD of the remote repository,
1221so often you can accomplish the above with just
1222
1223-------------------------------------------------
1224$ git pull
1225-------------------------------------------------
1226
1227See the descriptions of the branch.<name>.remote and
1228branch.<name>.merge options in gitlink:git-repo-config[1] to learn
1229how to control these defaults depending on the current branch.
1230
1231In addition to saving you keystrokes, "git pull" also helps you by
1232producing a default commit message documenting the branch and
1233repository that you pulled from.
1234
1235(But note that no such commit will be created in the case of a
1236<<fast-forwards,fast forward>>; instead, your branch will just be
1237updated to point to the latest commit from the upstream branch).
1238
4c63ff45
BF
1239The git-pull command can also be given "." as the "remote" repository, in
1240which case it just merges in a branch from the current repository; so
1241the commands
1242
1243-------------------------------------------------
1244$ git pull . branch
1245$ git merge branch
1246-------------------------------------------------
1247
1248are roughly equivalent. The former is actually very commonly used.
1249
d19fbc3c 1250Submitting patches to a project
b684f830 1251-------------------------------
d19fbc3c
BF
1252
1253If you just have a few changes, the simplest way to submit them may
1254just be to send them as patches in email:
1255
1256First, use gitlink:git-format-patches[1]; for example:
1257
1258-------------------------------------------------
1259$ git format-patches origin
1260-------------------------------------------------
1261
1262will produce a numbered series of files in the current directory, one
1263for each patch in the current branch but not in origin/HEAD.
1264
1265You can then import these into your mail client and send them by
1266hand. However, if you have a lot to send at once, you may prefer to
1267use the gitlink:git-send-email[1] script to automate the process.
1268Consult the mailing list for your project first to determine how they
1269prefer such patches be handled.
1270
1271Importing patches to a project
b684f830 1272------------------------------
d19fbc3c
BF
1273
1274Git also provides a tool called gitlink:git-am[1] (am stands for
1275"apply mailbox"), for importing such an emailed series of patches.
1276Just save all of the patch-containing messages, in order, into a
1277single mailbox file, say "patches.mbox", then run
1278
1279-------------------------------------------------
1280$ git am patches.mbox
1281-------------------------------------------------
1282
1283Git will apply each patch in order; if any conflicts are found, it
1284will stop, and you can fix the conflicts as described in
1285"<<resolving-a-merge,Resolving a merge>>". Once the index is updated
1286with the results of the conflict resolution, instead of creating a
1287new commit, just run
1288
1289-------------------------------------------------
1290$ git am --resolved
1291-------------------------------------------------
1292
1293and git will create the commit for you and continue applying the
1294remaining patches from the mailbox.
1295
1296The final result will be a series of commits, one for each patch in
1297the original mailbox, with authorship and commit log message each
1298taken from the message containing each patch.
1299
1300[[setting-up-a-public-repository]]
1301Setting up a public repository
b684f830 1302------------------------------
d19fbc3c
BF
1303
1304Another way to submit changes to a project is to simply tell the
1305maintainer of that project to pull from your repository, exactly as
1306you did in the section "<<getting-updates-with-git-pull, Getting
1307updates with git pull>>".
1308
1309If you and maintainer both have accounts on the same machine, then
1310then you can just pull changes from each other's repositories
1311directly; note that all of the command (gitlink:git-clone[1],
1312git-fetch[1], git-pull[1], etc.) which accept a URL as an argument
1313will also accept a local file patch; so, for example, you can
1314use
1315
1316-------------------------------------------------
1317$ git clone /path/to/repository
1318$ git pull /path/to/other/repository
1319-------------------------------------------------
1320
1321If this sort of setup is inconvenient or impossible, another (more
1322common) option is to set up a public repository on a public server.
1323This also allows you to cleanly separate private work in progress
1324from publicly visible work.
1325
1326You will continue to do your day-to-day work in your personal
1327repository, but periodically "push" changes from your personal
1328repository into your public repository, allowing other developers to
1329pull from that repository. So the flow of changes, in a situation
1330where there is one other developer with a public repository, looks
1331like this:
1332
1333 you push
1334 your personal repo ------------------> your public repo
1335 ^ |
1336 | |
1337 | you pull | they pull
1338 | |
1339 | |
1340 | they push V
1341 their public repo <------------------- their repo
1342
1343Now, assume your personal repository is in the directory ~/proj. We
1344first create a new clone of the repository:
1345
1346-------------------------------------------------
1347$ git clone --bare proj-clone.git
1348-------------------------------------------------
1349
1350The resulting directory proj-clone.git will contains a "bare" git
1351repository--it is just the contents of the ".git" directory, without
1352a checked-out copy of a working directory.
1353
1354Next, copy proj-clone.git to the server where you plan to host the
1355public repository. You can use scp, rsync, or whatever is most
1356convenient.
1357
1358If somebody else maintains the public server, they may already have
1359set up a git service for you, and you may skip to the section
1360"<<pushing-changes-to-a-public-repository,Pushing changes to a public
1361repository>>", below.
1362
1363Otherwise, the following sections explain how to export your newly
1364created public repository:
1365
1366[[exporting-via-http]]
1367Exporting a git repository via http
b684f830 1368-----------------------------------
d19fbc3c
BF
1369
1370The git protocol gives better performance and reliability, but on a
1371host with a web server set up, http exports may be simpler to set up.
1372
1373All you need to do is place the newly created bare git repository in
1374a directory that is exported by the web server, and make some
1375adjustments to give web clients some extra information they need:
1376
1377-------------------------------------------------
1378$ mv proj.git /home/you/public_html/proj.git
1379$ cd proj.git
1380$ git update-server-info
1381$ chmod a+x hooks/post-update
1382-------------------------------------------------
1383
1384(For an explanation of the last two lines, see
1385gitlink:git-update-server-info[1], and the documentation
1386link:hooks.txt[Hooks used by git].)
1387
1388Advertise the url of proj.git. Anybody else should then be able to
1389clone or pull from that url, for example with a commandline like:
1390
1391-------------------------------------------------
1392$ git clone http://yourserver.com/~you/proj.git
1393-------------------------------------------------
1394
1395(See also
1396link:howto/setup-git-server-over-http.txt[setup-git-server-over-http]
1397for a slightly more sophisticated setup using WebDAV which also
1398allows pushing over http.)
1399
1400[[exporting-via-git]]
1401Exporting a git repository via the git protocol
b684f830 1402-----------------------------------------------
d19fbc3c
BF
1403
1404This is the preferred method.
1405
1406For now, we refer you to the gitlink:git-daemon[1] man page for
1407instructions. (See especially the examples section.)
1408
1409[[pushing-changes-to-a-public-repository]]
1410Pushing changes to a public repository
b684f830 1411--------------------------------------
d19fbc3c
BF
1412
1413Note that the two techniques outline above (exporting via
1414<<exporting-via-http,http>> or <<exporting-via-git,git>>) allow other
1415maintainers to fetch your latest changes, but they do not allow write
1416access, which you will need to update the public repository with the
1417latest changes created in your private repository.
1418
1419The simplest way to do this is using gitlink:git-push[1] and ssh; to
1420update the remote branch named "master" with the latest state of your
1421branch named "master", run
1422
1423-------------------------------------------------
1424$ git push ssh://yourserver.com/~you/proj.git master:master
1425-------------------------------------------------
1426
1427or just
1428
1429-------------------------------------------------
1430$ git push ssh://yourserver.com/~you/proj.git master
1431-------------------------------------------------
1432
1433As with git-fetch, git-push will complain if this does not result in
1434a <<fast-forwards,fast forward>>. Normally this is a sign of
1435something wrong. However, if you are sure you know what you're
1436doing, you may force git-push to perform the update anyway by
1437proceeding the branch name by a plus sign:
1438
1439-------------------------------------------------
1440$ git push ssh://yourserver.com/~you/proj.git +master
1441-------------------------------------------------
1442
1443As with git-fetch, you may also set up configuration options to
1444save typing; so, for example, after
1445
1446-------------------------------------------------
1447$ cat >.git/config <<EOF
1448[remote "public-repo"]
1449 url = ssh://yourserver.com/~you/proj.git
1450EOF
1451-------------------------------------------------
1452
1453you should be able to perform the above push with just
1454
1455-------------------------------------------------
1456$ git push public-repo master
1457-------------------------------------------------
1458
1459See the explanations of the remote.<name>.url, branch.<name>.remote,
1460and remote.<name>.push options in gitlink:git-repo-config[1] for
1461details.
1462
1463Setting up a shared repository
b684f830 1464------------------------------
d19fbc3c
BF
1465
1466Another way to collaborate is by using a model similar to that
1467commonly used in CVS, where several developers with special rights
1468all push to and pull from a single shared repository. See
1469link:cvs-migration.txt[git for CVS users] for instructions on how to
1470set this up.
1471
b684f830
BF
1472Allow web browsing of a repository
1473----------------------------------
d19fbc3c 1474
b684f830 1475TODO: Brief setup-instructions for gitweb
d19fbc3c 1476
b684f830
BF
1477Examples
1478--------
d19fbc3c 1479
b684f830 1480TODO: topic branches, typical roles as in everyday.txt, ?
d19fbc3c 1481
d19fbc3c
BF
1482
1483Working with other version control systems
1484==========================================
1485
4c63ff45 1486TODO: CVS, Subversion, series-of-release-tarballs, ?
d19fbc3c
BF
1487
1488[[cleaning-up-history]]
4c63ff45
BF
1489Rewriting history and maintaining patch series
1490==============================================
1491
1492Normally commits are only added to a project, never taken away or
1493replaced. Git is designed with this assumption, and violating it will
1494cause git's merge machinery (for example) to do the wrong thing.
1495
1496However, there is a situation in which it can be useful to violate this
1497assumption.
1498
1499Creating the perfect patch series
1500---------------------------------
1501
1502Suppose you are a contributor to a large project, and you want to add a
1503complicated feature, and to present it to the other developers in a way
1504that makes it easy for them to read your changes, verify that they are
1505correct, and understand why you made each change.
1506
1507If you present all of your changes as a single patch (or commit), they may
1508find it is too much to digest all at once.
1509
1510If you present them with the entire history of your work, complete with
1511mistakes, corrections, and dead ends, they may be overwhelmed.
1512
1513So the ideal is usually to produce a series of patches such that:
1514
1515 1. Each patch can be applied in order.
1516
1517 2. Each patch includes a single logical change, together with a
1518 message explaining the change.
1519
1520 3. No patch introduces a regression: after applying any initial
1521 part of the series, the resulting project still compiles and
1522 works, and has no bugs that it didn't have before.
1523
1524 4. The complete series produces the same end result as your own
1525 (probably much messier!) development process did.
1526
1527We will introduce some tools that can help you do this, explain how to use
1528them, and then explain some of the problems that can arise because you are
1529rewriting history.
1530
1531Keeping a patch series up to date using git-rebase
1532--------------------------------------------------
1533
1534Suppose you have a series of commits in a branch "mywork", which
1535originally branched off from "origin".
1536
1537Suppose you create a branch "mywork" on a remote-tracking branch "origin",
1538and created some commits on top of it:
1539
1540-------------------------------------------------
1541$ git checkout -b mywork origin
1542$ vi file.txt
1543$ git commit
1544$ vi otherfile.txt
1545$ git commit
1546...
1547-------------------------------------------------
1548
1549You have performed no merges into mywork, so it is just a simple linear
1550sequence of patches on top of "origin":
1551
1552
1553 o--o--o <-- origin
1554 \
1555 o--o--o <-- mywork
1556
1557Some more interesting work has been done in the upstream project, and
1558"origin" has advanced:
1559
1560 o--o--O--o--o--o <-- origin
1561 \
1562 a--b--c <-- mywork
1563
1564At this point, you could use "pull" to merge your changes back in;
1565the result would create a new merge commit, like this:
1566
1567
1568 o--o--O--o--o--o <-- origin
1569 \ \
1570 a--b--c--m <-- mywork
1571
1572However, if you prefer to keep the history in mywork a simple series of
1573commits without any merges, you may instead choose to use
1574gitlink:git-rebase[1]:
1575
1576-------------------------------------------------
1577$ git checkout mywork
1578$ git rebase origin
1579-------------------------------------------------
1580
1581This will remove each of your commits from mywork, temporarily saving them
1582as patches (in a directory named ".dotest"), update mywork to point at the
1583latest version of origin, then apply each of the saved patches to the new
1584mywork. The result will look like:
1585
1586
1587 o--o--O--o--o--o <-- origin
1588 \
1589 a'--b'--c' <-- mywork
1590
1591In the process, it may discover conflicts. In that case it will stop and
1592allow you to fix the conflicts as described in
1593"<<resolving-a-merge,Resolving a merge>>". Once the index is updated with
1594the results of the conflict resolution, instead of creating a new commit,
1595just run
1596
1597-------------------------------------------------
1598$ git rebase --continue
1599-------------------------------------------------
1600
1601and git will continue applying the rest of the patches.
1602
1603At any point you may use the --abort option to abort this process and
1604return mywork to the state it had before you started the rebase:
1605
1606-------------------------------------------------
1607$ git rebase --abort
1608-------------------------------------------------
1609
1610Reordering or selecting from a patch series
1611-------------------------------------------
1612
1613Given one existing commit, the gitlink:git-cherry-pick[1] command allows
1614you to apply the change introduced by that commit and create a new commit
1615that records it.
1616
1617This can be useful for modifying a patch series.
1618
1619TODO: elaborate
1620
1621Other tools
1622-----------
1623
1624There are numerous other tools, such as stgit, which exist for the purpose
1625of maintianing a patch series. These are out of the scope of this manual.
1626
1627Problems with rewriting history
1628-------------------------------
1629
1630The primary problem with rewriting the history of a branch has to do with
1631merging.
1632
1633TODO: elaborate
d19fbc3c 1634
d19fbc3c
BF
1635
1636Git internals
1637=============
1638
1639Architectural overview
1640----------------------
1641
1642TODO: Sources, README, core-tutorial, tutorial-2.txt, technical/
1643
1644Glossary of git terms
1645=====================
1646
1647include::glossary.txt[]
1648
6bd9b682
BF
1649Notes and todo list for this manual
1650===================================
1651
1652This is a work in progress.
1653
1654The basic requirements:
1655 - It must be readable in order, from beginning to end, by someone
1656 intelligent with a basic grasp of the unix commandline, but
1657 without any special knowledge of git. If necessary, any other
1658 prerequisites should be specifically mentioned as they arise.
1659 - Whenever possible, section headings should clearly describe the
1660 task they explain how to do, in language that requires no more
1661 knowledge than necessary: for example, "importing patches into a
1662 project" rather than "the git-am command"
1663
d5cd5de4
BF
1664Think about how to create a clear chapter dependency graph that will
1665allow people to get to important topics without necessarily reading
1666everything in between.
d19fbc3c
BF
1667
1668Scan Documentation/ for other stuff left out; in particular:
1669 howto's
1670 README
1671 some of technical/?
1672 hooks
1673 etc.
1674
1675Scan email archives for other stuff left out
1676
1677Scan man pages to see if any assume more background than this manual
1678provides.
1679
d5cd5de4
BF
1680Simplify beginning by suggesting disconnected head instead of temporary
1681branch creation.
d19fbc3c
BF
1682
1683Explain how to refer to file stages in the "how to resolve a merge"
e9c0390a
BF
1684section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The
1685"git ls-files --unmerged --stage" thing is sorta useful too, actually. And
1686note gitk --merge. Also what's easiest way to see common merge base?
1687
b684f830
BF
1688Add more good examples. Entire sections of just cookbook examples might
1689be a good idea; maybe make an "advanced examples" section a standard
1690end-of-chapter section?
d19fbc3c
BF
1691
1692Include cross-references to the glossary, where appropriate.
1693
e9c0390a
BF
1694To document:
1695 reflogs, git reflog expire
1696 shallow clones?? See draft 1.5.0 release notes for some documentation.