Comprehensive reference documentation is available through the man
pages, or linkgit:git-help[1] command. For example, for the command
-"git clone <repo>", you can either use:
+`git clone <repo>`, you can either use:
------------------------------------------------
$ man git-clone
The initial clone may be time-consuming for a large project, but you
will only need to clone once.
-The clone command creates a new directory named after the project ("git"
-or "linux-2.6" in the examples above). After you cd into this
+The clone command creates a new directory named after the project (`git`
+or `linux-2.6` in the examples above). After you cd into this
directory, you will see that it contains a copy of the project files,
called the <<def_working_tree,working tree>>, together with a special
-top-level directory named ".git", which contains all the information
+top-level directory named `.git`, which contains all the information
about the history of the project.
[[how-to-check-out]]
did, and why.
Every commit has a 40-hexdigit id, sometimes called the "object name" or the
-"SHA-1 id", shown on the first line of the "git show" output. You can usually
+"SHA-1 id", shown on the first line of the `git show` output. You can usually
refer to a commit by a shorter name, such as a tag or a branch name, but this
longer name can also be useful. Most importantly, it is a globally unique
name for this commit: so if you tell somebody else the object name (for
Creating, deleting, and modifying branches is quick and easy; here's
a summary of the commands:
-git branch::
+`git branch`::
list all branches
-git branch <branch>::
- create a new branch named <branch>, referencing the same
+`git branch <branch>`::
+ create a new branch named `<branch>`, referencing the same
point in history as the current branch
-git branch <branch> <start-point>::
- create a new branch named <branch>, referencing
- <start-point>, which may be specified any way you like,
+`git branch <branch> <start-point>`::
+ create a new branch named `<branch>`, referencing
+ `<start-point>`, which may be specified any way you like,
including using a branch name or a tag name
-git branch -d <branch>::
- delete the branch <branch>; if the branch you are deleting
+`git branch -d <branch>`::
+ delete the branch `<branch>`; if the branch you are deleting
points to a commit which is not reachable from the current
branch, this command will fail with a warning.
-git branch -D <branch>::
+`git branch -D <branch>`::
even if the branch points to a commit not reachable
from the current branch, you may know that that commit
is still reachable from some other branch or tag. In that
case it is safe to use this command to force Git to delete
the branch.
-git checkout <branch>::
- make the current branch <branch>, updating the working
- directory to reflect the version referenced by <branch>
-git checkout -b <new> <start-point>::
- create a new branch <new> referencing <start-point>, and
+`git checkout <branch>`::
+ make the current branch `<branch>`, updating the working
+ directory to reflect the version referenced by `<branch>`
+`git checkout -b <new> <start-point>`::
+ create a new branch `<new>` referencing `<start-point>`, and
check it out.
The special symbol "HEAD" can always be used to refer to the current
-branch. In fact, Git uses a file named "HEAD" in the .git directory to
-remember which branch is current:
+branch. In fact, Git uses a file named `HEAD` in the `.git` directory
+to remember which branch is current:
------------------------------------------------
$ cat .git/HEAD
may also have had other branches, though, and your local repository
keeps branches which track each of those remote branches, called
remote-tracking branches, which you
-can view using the "-r" option to linkgit:git-branch[1]:
+can view using the `-r` option to linkgit:git-branch[1]:
------------------------------------------------
$ git branch -r
for short. The branches of this repository are called "remote
branches" from our point of view. The remote-tracking branches listed
above were created based on the remote branches at clone time and will
-be updated by "git fetch" (hence "git pull") and "git push". See
+be updated by `git fetch` (hence `git pull`) and `git push`. See
<<Updating-a-repository-With-git-fetch>> for details.
You might want to build on one of these remote-tracking branches
$ git checkout -b my-todo-copy origin/todo
------------------------------------------------
-You can also check out "origin/todo" directly to examine it or
+You can also check out `origin/todo` directly to examine it or
write a one-off patch. See <<detached-head,detached head>>.
Note that the name "origin" is just the name that Git uses by default
Branches, remote-tracking branches, and tags are all references to
commits. All references are named with a slash-separated path name
-starting with "refs"; the names we've been using so far are actually
+starting with `refs`; the names we've been using so far are actually
shorthand:
- - The branch "test" is short for "refs/heads/test".
- - The tag "v2.6.18" is short for "refs/tags/v2.6.18".
- - "origin/master" is short for "refs/remotes/origin/master".
+ - The branch `test` is short for `refs/heads/test`.
+ - The tag `v2.6.18` is short for `refs/tags/v2.6.18`.
+ - `origin/master` is short for `refs/remotes/origin/master`.
The full name is occasionally useful if, for example, there ever
exists a tag and a branch with the same name.
-(Newly created refs are actually stored in the .git/refs directory,
+(Newly created refs are actually stored in the `.git/refs` directory,
under the path given by their name. However, for efficiency reasons
they may also be packed together in a single file; see
linkgit:git-pack-refs[1]).
repository, creating new commits and advancing the branches to point
at the new commits.
-The command "git fetch", with no arguments, will update all of the
+The command `git fetch`, with no arguments, will update all of the
remote-tracking branches to the latest version found in her
repository. It will not touch any of your own branches--not even the
"master" branch that was created for you on clone.
-------------------------------------------------
New remote-tracking branches will be stored under the shorthand name
-that you gave "git remote add", in this case linux-nfs:
+that you gave `git remote add`, in this case `linux-nfs`:
-------------------------------------------------
$ git branch -r
origin/master
-------------------------------------------------
-If you run "git fetch <remote>" later, the remote-tracking branches for the
-named <remote> will be updated.
+If you run `git fetch <remote>` later, the remote-tracking branches
+for the named `<remote>` will be updated.
-If you examine the file .git/config, you will see that Git has added
+If you examine the file `.git/config`, you will see that Git has added
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
+or delete these configuration options by editing `.git/config` with a
text editor. (See the "CONFIGURATION FILE" section of
linkgit:git-config[1] for details.)
[65934a9a028b88e83e2b0f8b36618fe503349f8e] BLOCK: Make USB storage depend on SCSI rather than selecting it [try #6]
-------------------------------------------------
-If you run "git branch" at this point, you'll see that Git has
+If you run `git branch` at this point, you'll see that Git has
temporarily moved you in "(no branch)". HEAD is now detached from any
branch and points directly to a commit (with commit id 65934...) that
is reachable from "master" but not from v2.6.18. Compile and test it,
$ git reset --hard fb47ddb2db...
-------------------------------------------------
-then test, run "bisect good" or "bisect bad" as appropriate, and
+then test, run `bisect good` or `bisect bad` as appropriate, and
continue.
-Instead of "git bisect visualize" and then "git reset --hard
-fb47ddb2db...", you might just want to tell Git that you want to skip
+Instead of `git bisect visualize` and then `git reset --hard
+fb47ddb2db...`, you might just want to tell Git that you want to skip
the current commit:
-------------------------------------------------
There are also ways to automate the bisecting process if you have a
test script that can tell a good from a bad commit. See
-linkgit:git-bisect[1] for more information about this and other "git
-bisect" features.
+linkgit:git-bisect[1] for more information about this and other `git
+bisect` features.
[[naming-commits]]
Naming commits
-------------------------------------------------
Recall that merge commits may have more than one parent; by default,
-^ and ~ follow the first parent listed in the commit, but you can
+`^` and `~` follow the first parent listed in the commit, but you can
also choose:
-------------------------------------------------
$ git tag stable-1 1b2e1d63ff
-------------------------------------------------
-You can use stable-1 to refer to the commit 1b2e1d63ff.
+You can use `stable-1` to refer to the commit 1b2e1d63ff.
This creates a "lightweight" tag. If you would also like to include a
comment with the tag, and possibly sign it cryptographically, then you
-------------------------------------------------
And of course you can combine all of these; the following finds
-commits since v2.5 which touch the Makefile or any file under fs:
+commits since v2.5 which touch the `Makefile` or any file under `fs`:
-------------------------------------------------
$ git log v2.5.. Makefile fs/
$ git log -p
-------------------------------------------------
-See the "--pretty" option in the linkgit:git-log[1] man page for more
+See the `--pretty` option in the linkgit:git-log[1] man page for more
display options.
Note that git log starts with the most recent commit and works
Counting the number of commits on a branch
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Suppose you want to know how many commits you've made on "mybranch"
-since it diverged from "origin":
+Suppose you want to know how many commits you've made on `mybranch`
+since it diverged from `origin`:
-------------------------------------------------
$ git log --pretty=oneline origin..mybranch | wc -l
e05db0fd4f31dde7005f075a84f96b360d05984b
-------------------------------------------------
-Or you could recall that the ... operator selects all commits
+Or you could recall that the `...` operator selects all commits
contained reachable from either one reference or the other but not
both; so
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Suppose you would like to see all the commits reachable from the branch
-head named "master" but not from any other head in your repository.
+head named `master` but not from any other head in your repository.
We can list all the heads in this repository with
linkgit:git-show-ref[1]:
1e87486ae06626c2f31eaa63d26fc0fd646c8af2 refs/heads/tutorial-fixes
-------------------------------------------------
-We can get just the branch-head names, and remove "master", with
+We can get just the branch-head names, and remove `master`, with
the help of the standard utilities cut and grep:
-------------------------------------------------
the output file extension if possible, see linkgit:git-archive[1] for
details.
-Versions of Git older than 1.7.7 don't know about the 'tar.gz' format,
+Versions of Git older than 1.7.7 don't know about the `tar.gz` format,
you'll need to use gzip explicitly:
-------------------------------------------------
special staging area called "the index."
At the beginning, the content of the index will be identical to
-that of the HEAD. The command "git diff --cached", which shows
+that of the HEAD. The command `git diff --cached`, which shows
the difference between the HEAD and the index, should therefore
produce no output at that point.
shows the difference between the working tree and the index file.
-Note that "git add" always adds just the current contents of a file
+Note that `git add` always adds just the current contents of a file
to the index; further changes to the same file will be ignored unless
you run `git add` on the file again.
`git add .` practically useless, and they keep showing up in the output of
`git status`.
-You can tell Git to ignore certain files by creating a file called .gitignore
-in the top level of your working directory, with contents such as:
+You can tell Git to ignore certain files by creating a file called
+`.gitignore` in the top level of your working directory, with contents
+such as:
-------------------------------------------------
# Lines starting with '#' are considered comments.
If you wish the exclude patterns to affect only certain repositories
(instead of every repository for a given project), you may instead put
-them in a file in your repository named .git/info/exclude, or in any file
-specified by the `core.excludesfile` configuration variable. Some Git
-commands can also take exclude patterns directly on the command line.
-See linkgit:gitignore[5] for the details.
+them in a file in your repository named `.git/info/exclude`, or in any
+file specified by the `core.excludesfile` configuration variable.
+Some Git commands can also take exclude patterns directly on the
+command line. See linkgit:gitignore[5] for the details.
[[how-to-merge]]
How to merge
$ git merge branchname
-------------------------------------------------
-merges the development in the branch "branchname" into the current
+merges the development in the branch `branchname` into the current
branch.
-A merge is made by combining the changes made in "branchname" and the
+A merge is made by combining the changes made in `branchname` and the
changes made up to the latest commit in your current branch since
their histories forked. The work tree is overwritten by the result of
the merge when this combining is done cleanly, or overwritten by a
The diff above shows the differences between the working-tree version of
file.txt and the stage 2 and stage 3 versions. So instead of preceding
-each line by a single "+" or "-", it now uses two columns: the first
+each line by a single `+` or `-`, it now uses two columns: the first
column is used for differences between the first parent and the working
directory copy, and the second for differences between the second parent
and the working directory copy. (See the "COMBINED DIFF FORMAT" section
You will see informational messages on dangling objects. They are objects
that still exist in the repository but are no longer referenced by any of
-your branches, and can (and will) be removed after a while with "gc".
+your branches, and can (and will) be removed after a while with `gc`.
You can run `git fsck --no-dangling` to suppress these messages, and still
view real errors.
Reflogs
^^^^^^^
-Say you modify a branch with +linkgit:git-reset[1] \--hard+, and then
-realize that the branch was the only reference you had to that point in
-history.
+Say you modify a branch with <<fixing-mistakes,`git reset --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
-------------------------------------------------
This lists the commits reachable from the previous version of the
-"master" branch head. This syntax can be used with any Git command
-that accepts a commit, not just with git log. Some other examples:
+`master` branch head. This syntax can be used with any Git command
+that accepts a commit, not just with `git log`. Some other examples:
-------------------------------------------------
$ git show master@{2} # See where the branch pointed 2,
$ git pull origin master
-------------------------------------------------
-In fact, if you have "master" checked out, then this branch has been
-configured by "git clone" to get changes from the HEAD branch of the
+In fact, if you have `master` checked out, then this branch has been
+configured by `git clone` to get changes from the HEAD branch of the
origin repository. So often you can
accomplish the above with just a simple
More generally, a branch that is created from a remote-tracking branch
will pull
by default from that branch. See the descriptions of the
-branch.<name>.remote and branch.<name>.merge options in
+`branch.<name>.remote` and `branch.<name>.merge` options in
linkgit:git-config[1], and the discussion of the `--track` option in
linkgit:git-checkout[1], to learn how to control these defaults.
-In addition to saving you keystrokes, "git pull" also helps you by
+In addition to saving you keystrokes, `git pull` also helps you by
producing a default commit message documenting the branch and
repository that you pulled from.
<<fast-forwards,fast-forward>>; instead, your branch will just be
updated to point to the latest commit from the upstream branch.)
-The `git pull` command can also be given "." as the "remote" repository,
+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
-------------------------------------------------
will produce a numbered series of files in the current directory, one
-for each patch in the current branch but not in origin/HEAD.
+for each patch in the current branch but not in `origin/HEAD`.
`git format-patch` can include an initial "cover letter". You can insert
commentary on individual patches after the three dash line which
Git also provides a tool called linkgit: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
+single mailbox file, say `patches.mbox`, then run
-------------------------------------------------
$ git am -3 patches.mbox
Git will apply each patch in order; if any conflicts are found, it
will stop, and you can fix the conflicts as described in
-"<<resolving-a-merge,Resolving a merge>>". (The "-3" option tells
+"<<resolving-a-merge,Resolving a merge>>". (The `-3` option tells
Git to perform a merge; if you would prefer it just to abort and
leave your tree and index untouched, you may omit that option.)
Setting up a public repository
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Assume your personal repository is in the directory ~/proj. We
+Assume your personal repository is in the directory `~/proj`. We
first create a new clone of the repository and tell `git daemon` that it
is meant to be public:
-------------------------------------------------
The resulting directory proj.git contains a "bare" git repository--it is
-just the contents of the ".git" directory, without any files checked out
+just the contents of the `.git` directory, without any files checked out
around it.
-Next, copy proj.git to the server where you plan to host the
+Next, copy `proj.git` to the server where you plan to host the
public repository. You can use scp, rsync, or whatever is most
convenient.
This is the preferred method.
If someone else administers the server, they should tell you what
-directory to put the repository in, and what git:// URL it will appear
-at. You can then skip to the section
+directory to put the repository in, and what `git://` URL it will
+appear at. You can then skip to the section
"<<pushing-changes-to-a-public-repository,Pushing changes to a public
repository>>", below.
(For an explanation of the last two lines, see
linkgit:git-update-server-info[1] and linkgit:githooks[5].)
-Advertise the URL of proj.git. Anybody else should then be able to
+Advertise the URL of `proj.git`. Anybody else should then be able to
clone or pull from that URL, for example with a command line like:
-------------------------------------------------
latest changes created in your private repository.
The simplest way to do this is using linkgit:git-push[1] and ssh; to
-update the remote branch named "master" with the latest state of your
-branch named "master", run
+update the remote branch named `master` with the latest state of your
+branch named `master`, run
-------------------------------------------------
$ git push ssh://yourserver.com/~you/proj.git master:master
<<fast-forwards,fast-forward>>; see the following section for details on
handling this case.
-Note that the target of a "push" is normally a
+Note that the target of a `push` is normally a
<<def_bare_repository,bare>> repository. You can also push to a
repository that has a checked-out working tree, but a push to update the
currently checked-out branch is denied by default to prevent confusion.
$ git push public-repo master
-------------------------------------------------
-See the explanations of the remote.<name>.url, branch.<name>.remote,
-and remote.<name>.push options in linkgit:git-config[1] for
-details.
+See the explanations of the `remote.<name>.url`,
+`branch.<name>.remote`, and `remote.<name>.push` options in
+linkgit:git-config[1] for details.
[[forcing-push]]
What to do when a push fails
Now create the branches in which you are going to work; these start out
at the current tip of origin/master branch, and should be set up (using
-the --track option to linkgit:git-branch[1]) to merge changes in from
+the `--track` option to linkgit:git-branch[1]) to merge changes in from
Linus by default.
-------------------------------------------------
this merge will create a commit object in the history (with no local
changes Git will simply do a "fast-forward" merge). Many people dislike
the "noise" that this creates in the Linux history, so you should avoid
-doing this capriciously in the "release" branch, as these noisy commits
+doing this capriciously in the `release` branch, as these noisy commits
will become part of the permanent history when you ask Linus to pull
from the release branch.
Linus's branch. Picking a stable base for your branch will:
1) help you: by avoiding inclusion of unrelated and perhaps lightly
tested changes
-2) help future bug hunters that use "git bisect" to find problems
+2) help future bug hunters that use `git bisect` to find problems
-------------------------------------------------
$ git checkout -b speed-up-spinlocks v2.6.35
spent a while on this step and had also pulled new versions from upstream.
Some time later when enough time has passed and testing done, you can pull the
-same branch into the "release" tree ready to go upstream. This is where you
+same branch into the `release` tree ready to go upstream. This is where you
see the value of keeping each patch (or patch series) in its own branch. It
-means that the patches can be moved into the "release" tree in any order.
+means that the patches can be moved into the `release` tree in any order.
-------------------------------------------------
$ git checkout release && git pull . speed-up-spinlocks
Once a patch completes the great cycle (moving from test to release,
then pulled by Linus, and finally coming back into your local
-"origin/master" branch), the branch for this change is no longer needed.
+`origin/master` branch), the branch for this change is no longer needed.
You detect this when the output from:
-------------------------------------------------
Some changes are so trivial that it is not necessary to create a separate
branch and then merge into each of the test and release branches. For
-these changes, just apply directly to the "release" branch, and then
-merge that into the "test" branch.
+these changes, just apply directly to the `release` branch, and then
+merge that into the `test` branch.
After pushing your work to `mytree`, you can use
linkgit:git-request-pull[1] to prepare a "please pull" request message
fi
;;
*)
- echo "Usage: $0 origin|test|release" 1>&2
+ echo "usage: $0 origin|test|release" 1>&2
exit 1
;;
esac
usage()
{
- echo "Usage: $pname branch test|release" 1>&2
+ echo "usage: $pname branch test|release" 1>&2
exit 1
}
Keeping a patch series up to date using git rebase
--------------------------------------------------
-Suppose that you create a branch "mywork" on a remote-tracking branch
-"origin", and create some commits on top of it:
+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
-------------------------------------------------
You have performed no merges into mywork, so it is just a simple linear
-sequence of patches on top of "origin":
+sequence of patches on top of `origin`:
................................................
o--o--O <-- origin
................................................
Some more interesting work has been done in the upstream project, and
-"origin" has advanced:
+`origin` has advanced:
................................................
o--o--O--o--o--o <-- origin
a--b--c <-- mywork
................................................
-At this point, you could use "pull" to merge your changes back in;
+At this point, you could use `pull` to merge your changes back in;
the result would create a new merge commit, like this:
................................................
-------------------------------------------------
This will remove each of your commits from mywork, temporarily saving
-them as patches (in a directory named ".git/rebase-apply"), update mywork to
+them as patches (in a directory named `.git/rebase-apply`), update mywork to
point at the latest version of origin, then apply each of the saved
patches to the new mywork. The result will look like:
$ git fetch origin todo:my-todo-work
-------------------------------------------------
-The first argument, "origin", just tells Git to fetch from the
+The first argument, `origin`, just tells Git to fetch from the
repository you originally cloned from. The second argument tells Git
-to fetch the branch named "todo" from the remote repository, and to
-store it locally under the name refs/heads/my-todo-work.
+to fetch the branch named `todo` from the remote repository, and to
+store it locally under the name `refs/heads/my-todo-work`.
You can also fetch branches from other repositories; so
$ git fetch git://example.com/proj.git master:example-master
-------------------------------------------------
-will create a new branch named "example-master" and store in it the
-branch named "master" from the repository at the given URL. If you
+will create a new branch named `example-master` and store in it the
+branch named `master` from the repository at the given URL. If you
already have a branch named example-master, it will attempt to
<<fast-forwards,fast-forward>> to the commit given by example.com's
master branch. In more detail:
git fetch and fast-forwards
---------------------------
-In the previous example, when updating an existing branch, "git fetch"
+In the previous example, when updating an existing branch, `git fetch`
checks to make sure that the most recent commit on the remote
branch is a descendant of the most recent commit on your copy of the
branch before updating your copy of the branch to point at the new
o--o--o <-- new head of the branch
................................................
-In this case, "git fetch" will fail, and print out a warning.
+In this case, `git fetch` will fail, and print out a warning.
In that case, you can still force Git to update to the new head, as
described in the following section. However, note that in the
-situation above this may mean losing the commits labeled "a" and "b",
+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.
$ git fetch git://example.com/proj.git +master:refs/remotes/example/master
-------------------------------------------------
-Note the addition of the "+" sign. Alternatively, you can use the "-f"
+Note the addition of the `+` sign. Alternatively, you can use the `-f`
flag to force updates of all the fetched branches, as in:
-------------------------------------------------
Configuring remote-tracking branches
------------------------------------
-We saw above that "origin" is just a shortcut to refer to the
+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
linkgit:git-config[1]:
~~~~~~~~~~~~~
The "commit" object links a physical state of a tree with a description
-of how we got there and why. Use the --pretty=raw option to
+of how we got there and why. Use the `--pretty=raw` option to
linkgit:git-show[1] or linkgit:git-log[1] to examine your favorite
commit:
its parents. In particular, Git does not attempt to record file renames
explicitly, though it can identify cases where the existence of the same
file data at changing paths suggests a rename. (See, for example, the
--M option to linkgit:git-diff[1]).
+`-M` option to linkgit:git-diff[1]).
A commit is usually created by linkgit:git-commit[1], which creates a
commit whose parent is normally the current HEAD, and whose tree is
~~~~~~~~~~~
You can use linkgit:git-show[1] to examine the contents of a blob; take,
-for example, the blob in the entry for "COPYING" from the tree above:
+for example, the blob in the entry for `COPYING` from the tree above:
------------------------------------------------
$ git show 6ff87c4664
See the linkgit:git-tag[1] command to learn how to create and verify tag
objects. (Note that linkgit:git-tag[1] can also be used to create
"lightweight tags", which are not tag objects at all, but just simple
-references whose names begin with "refs/tags/").
+references whose names begin with `refs/tags/`).
[[pack-files]]
How Git stores objects efficiently: pack files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Newly created objects are initially created in a file named after the
-object's SHA-1 hash (stored in .git/objects).
+object's SHA-1 hash (stored in `.git/objects`).
Unfortunately this system becomes inefficient once a project has a
lot of objects. Try this on an old project:
to remove any of the "loose" objects that are now contained in the
pack. This will also remove any unreferenced objects (which may be
-created when, for example, you use "git reset" to remove a commit).
+created when, for example, you use `git reset` to remove a commit).
You can verify that the loose objects are gone by looking at the
-.git/objects directory or by running
+`.git/objects` directory or by running
------------------------------------------------
$ git count-objects
pointer itself just doesn't, since you replaced it with another one.
There are also other situations that cause dangling objects. For
-example, a "dangling blob" may arise because you did a "git add" of a
+example, a "dangling blob" may arise because you did a `git add` of a
file, but then, before you actually committed it and made it part of the
bigger picture, you changed something else in that file and committed
that *updated* thing--the old state that you added originally ends up
------------------------------------------------
to show what the contents of the blob were (or, for a tree, basically
-what the "ls" for that directory was), and that may give you some idea
+what the `ls` for that directory was), and that may give you some idea
of what the operation was that left that dangling object.
Usually, dangling blobs and trees aren't very interesting. They're
almost always the result of either being a half-way mergebase (the blob
will often even have the conflict markers from a merge in it, if you
have had conflicting merges that you fixed up by hand), or simply
-because you interrupted a "git fetch" with ^C or something like that,
+because you interrupted a `git fetch` with ^C or something like that,
leaving _some_ of the new objects in the object database, but just
dangling and useless.
$ git prune
------------------------------------------------
-and they'll be gone. But you should only run "git prune" on a quiescent
+and they'll be gone. But you should only run `git prune` on a quiescent
repository--it's kind of like doing a filesystem fsck recovery: you
don't want to do that while the filesystem is mounted.
-(The same is true of "git fsck" itself, btw, but since
+(The same is true of `git fsck` itself, btw, but since
`git fsck` never actually *changes* the repository, it just reports
on what it found, `git fsck` itself is never 'dangerous' to run.
Running it while somebody is actually changing the repository can cause
confusing and scary messages, but it won't actually do anything bad. In
-contrast, running "git prune" while somebody is actively changing the
+contrast, running `git prune` while somebody is actively changing the
repository is a *BAD* idea).
[[recovering-from-repository-corruption]]
Now you know that blob 4b9458b3 is missing, and that the tree 2d9263c6
points to it. If you could find just one copy of that missing blob
object, possibly in some other repository, you could move it into
-.git/objects/4b/9458b3... and be done. Suppose you can't. You can
+`.git/objects/4b/9458b3...` and be done. Suppose you can't. You can
still examine the tree that pointed to it with linkgit:git-ls-tree[1],
which might output something like:
------------------------------------------------
So now you know that the missing blob was the data for a file named
-"myfile". And chances are you can also identify the directory--let's
-say it's in "somedirectory". If you're lucky the missing copy might be
+`myfile`. And chances are you can also identify the directory--let's
+say it's in `somedirectory`. If you're lucky the missing copy might be
the same as the copy you have checked out in your working tree at
-"somedirectory/myfile"; you can test whether that's right with
+`somedirectory/myfile`; you can test whether that's right with
linkgit:git-hash-object[1]:
------------------------------------------------
and your repository is good again!
-(Btw, you could have ignored the fsck, and started with doing a
+(Btw, you could have ignored the `fsck`, and started with doing a
------------------------------------------------
$ git log --raw --all
The index
-----------
-The index is a binary file (generally kept in .git/index) containing a
+The index is a binary file (generally kept in `.git/index`) containing a
sorted list of path names, each with permissions and the SHA-1 of a blob
object; linkgit:git-ls-files[1] can show you the contents of the index:
The `git submodule add <repo> <path>` command does a couple of things:
-- It clones the submodule from <repo> to the given <path> under the
+- It clones the submodule from `<repo>` to the given `<path>` under the
current directory and by default checks out the master branch.
- It adds the submodule's clone path to the linkgit:gitmodules[5] file and
adds this file to the index, ready to be committed.
In older Git versions it could be easily forgotten to commit new or modified
files in a submodule, which silently leads to similar problems as not pushing
-the submodule changes. Starting with Git 1.7.0 both "git status" and "git diff"
+the submodule changes. Starting with Git 1.7.0 both `git status` and `git diff`
in the superproject show submodules as modified when they contain new or
-modified files to protect against accidentally committing such a state. "git
-diff" will also add a "-dirty" to the work tree side when generating patch
-output or used with the --submodule option:
+modified files to protect against accidentally committing such a state. `git
+diff` will also add a `-dirty` to the work tree side when generating patch
+output or used with the `--submodule` option:
-------------------------------------------------
$ git diff
NOTE! `git checkout-index` normally refuses to overwrite old files, so
if you have an old version of the tree already checked out, you will
-need to use the "-f" flag ('before' the "-a" flag or the filename) to
+need to use the `-f` flag ('before' the `-a` flag or the filename) to
'force' the checkout.
Tying it all together
~~~~~~~~~~~~~~~~~~~~~
-To commit a tree you have instantiated with "git write-tree", you'd
+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.
independently of the contents or the type of the object: all objects can
be validated by verifying that (a) their hashes match the content of the
file and (b) the object successfully inflates to a stream of bytes that
-forms a sequence of <ascii type without space> {plus} <space> {plus} <ascii decimal
-size> {plus} <byte\0> {plus} <binary object data>.
+forms a sequence of
+`<ascii type without space> + <space> + <ascii decimal size> +
+<byte\0> + <binary object data>`.
The structured objects can further have their structure and
connectivity to other objects verified. This is generally done with
allow people to get to important topics without necessarily reading
everything in between.
-Scan Documentation/ for other stuff left out; in particular:
+Scan `Documentation/` for other stuff left out; in particular:
- howto's
-- some of technical/?
+- some of `technical/`?
- hooks
- list of commands in linkgit:git[1]