Table of Contents
This manual is designed to be readable by someone with basic unix +
Table of Contents
This manual is designed to be readable by someone with basic unix command-line 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
@@ -23,7 +23,7 @@ $
origin/master
origin/next
...
-$ git branch checkout -b masterwork origin/master
Fetch a branch from a different repository, and give it a new +$ git 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
@@ -59,8 +59,8 @@ $
$ git bisect bad # if this revision is bad.
# repeat until done.
Make sure git knows who to blame:
$ cat >~/.gitconfig <<\EOF
[user]
-name = Your Name Comes Here
-email = you@yourdomain.example.com
+ 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
@@ -71,7 +71,7 @@ $
# fetch and merge in remote branch
$ git pull . test # equivalent to git merge test
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 +$ 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
@@ -264,7 +264,7 @@ 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.
You can also track branches from repositories other than the one you cloned from, using git-remote(1):
$ git remote add linux-nfs git://linux-nfs.org/pub/nfs-2.6.git
-$ git fetch
+$ git fetch linux-nfs
* 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
@@ -279,12 +279,12 @@ a new stanza:
$ ...
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 -git-config(1) for details.)
Table of Contents
Git is best thought of as a tool for storing the history of a +git-config(1) for details.)
Table of Contents
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 that is useful for finding the -commit that introduced a bug into a project.
Suppose version 2.6.18 of your project worked, but the version at +commit that introduced a bug into a project.
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 @@ -309,10 +309,10 @@ temporary "bisect" branch.
Note that the version which git-bisect checks o 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 +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.
We have seen several ways of naming commits already:
We have seen several ways of naming commits already:
The 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
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 git-tag(1) man -page for details.
The git-log(1) command can show lists of commits. On its +page for details.
The 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
@@ -362,15 +362,15 @@ commits since v2.5 which touch the Makefile or any file under fs:
Note that git log starts with the most recent commit and works backwards through the parents; however, since git history can contain multiple independent lines of development, the particular order that -commits are listed in may be somewhat arbitrary.
You can generate diffs between any two versions using +commits are listed in may be somewhat arbitrary.
You can generate diffs between any two versions using 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.
You can always view an old version of a file by just checking out the +will not be the same as the diff produced by the git-diff example.
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.
Suppose you want to check whether two branches point at the same point +may be any path to a file tracked by git.
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
@@ -379,16 +379,16 @@ 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.
Suppose you know that the commit e05db0fd fixed a certain problem. +both: so
$ git log origin...master
will return no commits when the two branches are equal.
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 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
+descendants:
$ git name-rev --tags e05db0fd
e05db0fd tags/v1.5.0-rc1^0~23
The 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 +v1.5.0-rc0-260-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 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,
@@ -406,13 +406,13 @@ available
! [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.
Table of Contents
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 git-config(1) for -details on the configuration file.)
Creating a new repository from scratch is very easy:
$ mkdir project
+details on the configuration file.)
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
@@ -443,12 +443,12 @@ about to commit:
$
$ 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.
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.
You can rejoin two diverging branches of development using 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 @@ -476,7 +476,7 @@ $ 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.
The above is all you need to know to resolve a simple merge. But git -also provides more information to help resolve conflicts:
All of the changes that git was able to merge automatically are +also provides more information to help resolve conflicts:
All of the changes that git was able to merge automatically are already added to the index file, so git-diff(1) shows only the conflicts. It uses an unusual syntax:
$ git diff
diff --cc file.txt
@@ -530,7 +530,7 @@ git-diff will (by default) no longer show diffs for that file.
$ git reset --hard HEAD
Or, if you've already commited the merge that you want to throw away,
$ git reset --hard ORIG_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.
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 @@ -538,7 +538,7 @@ contained within the other—so every commit present in the one is already contained in the other—then git just performs a fast forward; 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.
If you've messed up the working tree, but haven't yet committed your +any new commits being created.
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:
Creating a new commit that reverts an earlier change is very easy; +
Creating a new commit that reverts an earlier change is very easy; just pass the 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 @@ -566,17 +566,17 @@ changes, giving you a chance to edit the old commit message first.
Again, been merged into another branch; use 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 -another chapter.
In the process of undoing a previous bad change, you may find it +another chapter.
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 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 -git-show(1):
$ git show HEAD^:path/to/file
which will display the given version of the file.
On large repositories, git depends on compression to keep the history +git-show(1):
$ git show HEAD^:path/to/file
which will display the given version of the file.
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 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.
The git-fsck(1) command runs a number of self-consistency checks +you may prefer to run git-gc when you are not doing other work.
The 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
@@ -591,7 +591,7 @@ dangling
you can remove them at any time with git-prune(1) or the —prune
option to 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 the section called “Dangling objects”.
Say you modify a branch with git-reset(1) —hard, and then +other git operations are in progress in the same repository.
For more about dangling objects, see the section called “Dangling objects”.
Say you modify a branch with 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 @@ -606,7 +606,7 @@ how to control this pruning, and see the "SPECIFYING REVISIONS" section of 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.
In some situations the reflog may not be able to save you. For +how the branches in your local repository have changed over time.
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 contained. The reflog is also deleted; however, if you have not yet pruned the repository, then you may still be able to find @@ -623,7 +623,7 @@ 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 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
Table of Contents
Table of Contents
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 how to keep remote tracking branches up to date with git-fetch(1), and how to merge two branches. So you can merge in changes from the @@ -640,13 +640,13 @@ repository that you pulled from.
(But note that no such commit will be cre 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.
If you just have a few changes, the simplest way to submit them may +$ git merge branch
are roughly equivalent. The former is actually very commonly used.
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 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 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.
Git also provides a tool called git-am(1) (am stands for +prefer such patches be handled.
Git also provides a tool called 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 @@ -718,16 +718,16 @@ save typing; so, for example, after
$
url = ssh://yourserver.com/~you/proj.git
EOF
you should be able to perform the above push with just
$ git push public-repo master
See the explanations of the remote.<name>.url, branch.<name>.remote, and remote.<name>.push options in git-config(1) for -details.
Another way to collaborate is by using a model similar to that +details.
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 git for CVS users for instructions on how to -set this up.
The gitweb cgi script provides users an easy way to browse your +set this up.
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.
Table of Contents
Normally commits are only added to a project, never taken away or +gitweb/INSTALL in the git source tree for instructions on setting it up.
Table of Contents
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.
Suppose you are a contributor to a large project, and you want to add a +assumption.
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 @@ -746,7 +746,7 @@ 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.
Suppose that you create a branch "mywork" on a remote-tracking branch +you are rewriting history.
Suppose that you create a branch "mywork" on a remote-tracking branch "origin", and create some commits on top of it:
$ git checkout -b mywork origin
$ vi file.txt
$ git commit
@@ -773,7 +773,7 @@ patches to the new mywork. The result will look like:
$ 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
We saw in the section called “Fixing a mistake by editing history” that you can replace the +return mywork to the state it had before you started the rebase:
$ git rebase --abort
We saw in the section called “Fixing a mistake by editing history” that you can replace the most recent commit using
$ 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.
You can also use a combination of this and git-rebase(1) to edit commits further back in your history. First, tag the problematic commit with
$ git tag bad mywork~5
(Either gitk or git-log may be useful for finding the commit.)
Then check out a new branch at that commit, edit it, and rebase the rest of @@ -785,7 +785,7 @@ on mywork reapplied on top of the modified commit you created in TMP. You can then clean up with
$ git branch -d TMP
$ git tag -d bad
Note that the immutable nature of git history means that you haven't really "modified" existing commits; instead, you have replaced the old commits with -new commits having new object names.
Given one existing commit, the git-cherry-pick(1) command +new commits having new object names.
Given one existing commit, the 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
@@ -795,9 +795,9 @@ 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 git-am(1).
There are numerous other tools, such as stgit, which exist for the +them again with git-am(1).
There are numerous other tools, such as stgit, which exist for the purpose of maintaining a patch series. These are outside of the scope of -this manual.
The primary problem with rewriting the history of a branch has to do +this manual.
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
\ \
@@ -818,7 +818,7 @@ new. The results are likely to be unexpected.You may still choose to pub
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.
Table of Contents
Instead of using git-remote(1), you can also choose just +published branches should never be rewritten.
Table of Contents
Instead of using 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 @@ -842,10 +842,10 @@ resulting in a situation like:
o--o--o--o--a--b & 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.
If git fetch fails because the new head of a branch is not a +them.
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 that the old version of example/master pointed at may be lost, as we saw in -the previous section.
We saw above that "origin" is just a shortcut to refer to the +the previous section.
We saw above that "origin" is just a shortcut to refer to the repository that you originally cloned from. This information is stored in git configuration variables, which you can see using git-config(1):
$ git config -l
@@ -865,8 +865,8 @@ $
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 git-config(1).
See git-config(1) for more details on the configuration -options mentioned above.
Table of Contents
There are two object abstractions: the "object database", and the -"current directory cache" aka "index".
Table of Contents
There are two object abstractions: the "object database", and the +"current directory cache" aka "index".
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 @@ -908,7 +908,7 @@ size> + <byte\0> + <binary object data>.
The structured obj
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:
A "blob" object is nothing but a binary blob of data, and doesn't +to just verifying their superficial consistency through the hash).
The object types in some more detail:
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 @@ -920,7 +920,7 @@ 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 git-update-index(1) -is run, and its data can be accessed by git-cat-file(1).
The next hierarchical object type is the "tree" object. A tree object +is run, and its data can be accessed by git-cat-file(1).
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 @@ -959,7 +959,7 @@ 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 git-commit-tree(1) and -its data can be accessed by git-cat-file(1).
An aside on the notion of "trust". Trust is really outside the scope +its data can be accessed by git-cat-file(1).
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 @@ -975,7 +975,7 @@ 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…
Git provides the "tag" object to simplify creating, managing and +like GPG/PGP.
To assist in this, git also provides the 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 @@ -985,7 +985,7 @@ integrity; the trust framework (and signature provision and verification) has to come from outside.
A tag is created with git-mktag(1), its data can be accessed by git-cat-file(1), and the signature can be verified by -git-verify-tag(1).
The index is a simple binary file, which contains an efficient +git-verify-tag(1).
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 @@ -1018,11 +1018,11 @@ 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.
Generally, all "git" operations work on the index file. Some operations +been written back to the backing store.
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:
You update the index with information from the working directory with +main combinations:
You update the index with information from the working directory with the 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 @@ -1038,16 +1038,16 @@ does not exist any more, it will update the index accordingly.
As a specia 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.
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 +an object still matches its old backing store object.
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:
You read a "tree" file from the object database, and use that to +other direction:
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 <sha1 of 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.
You update your working directory from the index by "checking out" +directory contents have not been modified.
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 @@ -1058,7 +1058,7 @@ with
$ 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:
To commit a tree you have instantiated with "git-write-tree", you'd +from one representation to the other:
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 @@ -1107,7 +1107,7 @@ various pieces fit together.
| Working |
| Directory |
+-----------+
-
You can examine the data represented in the object database and the index with various helper tools. For every object, you can use git-cat-file(1) to examine details about the object:
$ git-cat-file -t <objectname>
shows the type of the object, and once you have the type (which is @@ -1117,7 +1117,7 @@ there is a special helper for showing that content, called 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.
Git helps you do a three-way merge, which you can expand to n-way by +you can do
$ git-cat-file commit HEAD
to see what the top commit was.
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 @@ -1136,7 +1136,7 @@ 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 <origtree> <yourtree> <targettree>
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.
Sadly, many merges aren't trivial. If there are files that have
+git-write-tree.
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 @@ -1171,7 +1171,7 @@ that path tells git to mark the path resolved.
The above is the descriptio
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 merge -s resolve is implemented with.
We've seen how git stores each object in a file named after 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 merge -s resolve is implemented with.
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 @@ -1235,7 +1235,7 @@ 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).
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 diff --git a/user-manual.txt b/user-manual.txt index 1c49e6995..574e9c0e5 100644 --- a/user-manual.txt +++ b/user-manual.txt @@ -84,7 +84,7 @@ $ git branch -r # list origin/master origin/next ... -$ git branch checkout -b masterwork origin/master +$ git checkout -b masterwork origin/master ----------------------------------------------- Fetch a branch from a different repository, and give it a new @@ -155,8 +155,8 @@ Make sure git knows who to blame: ------------------------------------------------ $ cat >~/.gitconfig <<\EOF [user] -name = Your Name Comes Here -email = you@yourdomain.example.com + name = Your Name Comes Here + email = you@yourdomain.example.com EOF ------------------------------------------------ @@ -195,7 +195,7 @@ 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" +$ git am mbox # import patches from the mailbox "mbox" ----------------------------------------------- Fetch a branch in a different git repository, then merge into the @@ -579,7 +579,7 @@ cloned from, using gitlink:git-remote[1]: ------------------------------------------------- $ git remote add linux-nfs git://linux-nfs.org/pub/nfs-2.6.git -$ git fetch +$ git fetch linux-nfs * refs/remotes/linux-nfs/master: storing branch 'master' ... commit: bf81b46 ------------------------------------------------- @@ -680,7 +680,7 @@ occasionally you may land on a commit that broke something unrelated; run ------------------------------------------------- -$ git bisect-visualize +$ git bisect visualize ------------------------------------------------- which will run gitk and label the commit it chose with a marker that @@ -765,7 +765,7 @@ We can also create a tag to refer to a particular commit; after running ------------------------------------------------- -$ git-tag stable-1 1b2e1d63ff +$ git tag stable-1 1b2e1d63ff ------------------------------------------------- You can use stable-1 to refer to the commit 1b2e1d63ff. @@ -909,7 +909,7 @@ name based on any tag it finds pointing to one of the commit's descendants: ------------------------------------------------- -$ git name-rev e05db0fd +$ git name-rev --tags e05db0fd e05db0fd tags/v1.5.0-rc1^0~23 ------------------------------------------------- @@ -918,7 +918,7 @@ revision using a tag on which the given commit is based: ------------------------------------------------- $ git describe e05db0fd -v1.5.0-rc0-ge05db0f +v1.5.0-rc0-260-ge05db0f ------------------------------------------------- but that may sometimes help you guess which tags might come after the @@ -1861,7 +1861,7 @@ 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. +gitweb/INSTALL in the git source tree for instructions on setting it up. Examples -------- -- 2.26.2