subdirectory, and initialize the git infrastructure with `git-init-db`:
------------------------------------------------
-mkdir git-tutorial
-cd git-tutorial
-git-init-db
+$ mkdir git-tutorial
+$ cd git-tutorial
+$ git-init-db
------------------------------------------------
to which git will reply
- defaulting to local storage area
+----------------
+defaulting to local storage area
+----------------
which is just git's way of saying that you haven't been doing anything
strange, and that it will have created a local `.git` directory setup for
get a feel for how this works:
------------------------------------------------
-echo "Hello World" >hello
-echo "Silly example" >example
+$ echo "Hello World" >hello
+$ echo "Silly example" >example
------------------------------------------------
you have now created two files in your working tree (aka 'working directory'), but to
So to populate the index with the two files you just created, you can do
------------------------------------------------
-git-update-index --add hello example
+$ git-update-index --add hello example
------------------------------------------------
and you have now told git to track those two files.
you'll notice that git will have added two new objects to the object
database. If you did exactly the steps above, you should now be able to do
- ls .git/objects/??/*
+
+----------------
+$ ls .git/objects/??/*
+----------------
and see two files:
- .git/objects/55/7db03de997c86a4a028e1ebd3a1ceb225be238
- .git/objects/f2/4c74a2e500f5ee1332c86b94199f52b1d1d962
+----------------
+.git/objects/55/7db03de997c86a4a028e1ebd3a1ceb225be238
+.git/objects/f2/4c74a2e500f5ee1332c86b94199f52b1d1d962
+----------------
which correspond with the objects with names of 557db... and f24c7..
respectively.
If you want to, you can use `git-cat-file` to look at those objects, but
you'll have to use the object name, not the filename of the object:
- git-cat-file -t 557db03de997c86a4a028e1ebd3a1ceb225be238
+----------------
+$ git-cat-file -t 557db03de997c86a4a028e1ebd3a1ceb225be238
+----------------
where the `-t` tells `git-cat-file` to tell you what the "type" of the
object is. git will tell you that you have a "blob" object (ie just a
regular file), and you can see the contents with
- git-cat-file "blob" 557db03
+----------------
+$ git-cat-file "blob" 557db03
+----------------
which will print out "Hello World". The object 557db03 is nothing
more than the contents of your file `hello`.
start off by adding another line to `hello` first:
------------------------------------------------
-echo "It's a new day for git" >>hello
+$ echo "It's a new day for git" >>hello
------------------------------------------------
and you can now, since you told git about the previous state of `hello`, ask
`git-diff-files` command:
------------
-git-diff-files
+$ git-diff-files
------------
Oops. That wasn't very readable. It just spit out its own internal
differences as a patch, using the `-p` flag:
------------
-git-diff-files -p
-------------
-
-which will spit out
-
-------------
+$ git-diff-files -p
diff --git a/hello b/hello
index 557db03..263414f 100644
--- a/hello
creating the equivalent of a git "directory" object:
------------------------------------------------
-git-write-tree
+$ git-write-tree
------------------------------------------------
and this will just output the name of the resulting tree, in this case
(if you have done exactly as I've described) it should be
- 8988da15d077d4829fc51d8544c097def6644dbb
+----------------
+8988da15d077d4829fc51d8544c097def6644dbb
+----------------
which is another incomprehensible object name. Again, if you want to,
you can use `git-cat-file -t 8988d\...` to see that this time the object
all with a sequence of simple shell commands:
------------------------------------------------
-tree=$(git-write-tree)
-commit=$(echo 'Initial commit' | git-commit-tree $tree)
-git-update-ref HEAD $commit
+$ tree=$(git-write-tree)
+$ commit=$(echo 'Initial commit' | git-commit-tree $tree)
+$ git-update-ref HEAD $commit
------------------------------------------------
which will say:
- Committing initial tree 8988da15d077d4829fc51d8544c097def6644dbb
+----------------
+Committing initial tree 8988da15d077d4829fc51d8544c097def6644dbb
+----------------
just to warn you about the fact that it created a totally new commit
that is not related to anything else. Normally you do this only *once*
But now we can do
- git-diff-index -p HEAD
+----------------
+$ git-diff-index -p HEAD
+----------------
(where `-p` has the same meaning as it did in `git-diff-files`), and it
will show us the same difference, but for a totally different reason.
Again, because this is a common operation, you can also just shorthand
it with
- git diff HEAD
+----------------
+$ git diff HEAD
+----------------
which ends up doing the above for you.
update the index cache:
------------------------------------------------
-git-update-index hello
+$ git-update-index hello
------------------------------------------------
(note how we didn't need the `\--add` flag this time, since git knew
already, so let's just use the helpful script this time:
------------------------------------------------
-git commit
+$ git commit
------------------------------------------------
which starts an editor for you to write the commit message and tells you
of that commit itself, and show the difference directly. Thus, to get
the same diff that we've already seen several times, we can now do
- git-diff-tree -p HEAD
+----------------
+$ git-diff-tree -p HEAD
+----------------
(again, `-p` means to show the difference as a human-readable patch),
and it will show what the last commit (in `HEAD`) actually changed.
To see the whole history of our pitiful little git-tutorial project, you
can do
- git log
+----------------
+$ git log
+----------------
which shows just the log messages, or if we want to see the log together
with the associated patches use the more complex (and much more
powerful)
- git-whatchanged -p --root
+----------------
+$ git-whatchanged -p --root
+----------------
and you will see exactly what has changed in the repository over its
short history.
So the simplest form of tag involves nothing more than
------------------------------------------------
-git tag my-first-tag
+$ git tag my-first-tag
------------------------------------------------
which just writes the current `HEAD` into the `.git/refs/tags/my-first-tag`
file, after which point you can then use this symbolic name for that
particular state. You can, for example, do
- git diff my-first-tag
+----------------
+$ git diff my-first-tag
+----------------
to diff your current state against that tag (which at this point will
obviously be an empty diff, but if you continue to develop and commit
that tag. You create these annotated tags with either the `-a` or
`-s` flag to `git tag`:
- git tag -s <tagname>
+----------------
+$ git tag -s <tagname>
+----------------
which will sign the current `HEAD` (but you can also give it another
argument that specifies the thing to tag, ie you could have tagged the
Copying repositories
--------------------
-git repositories are normally totally self-sufficient, and it's worth noting
-that unlike CVS, for example, there is no separate notion of
+git repositories are normally totally self-sufficient and relocatable
+Unlike CVS, for example, there is no separate notion of
"repository" and "working tree". A git repository normally *is* the
working tree, with the local git information hidden in the `.git`
subdirectory. There is nothing else. What you see is what you got.
- if you grow bored with the tutorial repository you created (or you've
made a mistake and want to start all over), you can just do simple
-
- rm -rf git-tutorial
++
+----------------
+$ rm -rf git-tutorial
+----------------
+
and it will be gone. There's no external repository, and there's no
history outside the project you created.
file (which caches various information, notably some of the "stat"
information for the files involved) will likely need to be refreshed.
So after you do a `cp -a` to create a new copy, you'll want to do
-
- git-update-index --refresh
++
+----------------
+$ git-update-index --refresh
+----------------
+
in the new repository to make sure that the index file is up-to-date.
known state (you don't know *what* they've done and not yet checked in),
so usually you'll precede the `git-update-index` with a
- git-read-tree --reset HEAD
- git-update-index --refresh
+----------------
+$ git-read-tree --reset HEAD
+$ git-update-index --refresh
+----------------
which will force a total index re-build from the tree pointed to by `HEAD`.
It resets the index contents to `HEAD`, and then the `git-update-index`
The above can also be written as simply
- git reset
+----------------
+$ git reset
+----------------
and in fact a lot of the common git command combinations can be scripted
with the `git xyz` interfaces. You can learn things by just looking
raw repository contents into the `.git` directory. For example, to
create your own copy of the git repository, you'd do the following
- mkdir my-git
- cd my-git
- rsync -rL rsync://rsync.kernel.org/pub/scm/git/git.git/ .git
+----------------
+$ mkdir my-git
+$ cd my-git
+$ rsync -rL rsync://rsync.kernel.org/pub/scm/git/git.git/ .git
+----------------
followed by
- git-read-tree HEAD
+----------------
+$ git-read-tree HEAD
+----------------
to populate the index. However, now you have populated the index, and
you have all the git internal files, but you will notice that you don't
actually have any of the working tree files to work on. To get
those, you'd check them out with
- git-checkout-index -u -a
+----------------
+$ git-checkout-index -u -a
+----------------
where the `-u` flag means that you want the checkout to keep the index
up-to-date (so that you don't have to refresh it afterward), and the
Again, this can all be simplified with
- git clone rsync://rsync.kernel.org/pub/scm/git/git.git/ my-git
- cd my-git
- git checkout
+----------------
+$ git clone rsync://rsync.kernel.org/pub/scm/git/git.git/ my-git
+$ cd my-git
+$ git checkout
+----------------
which will end up doing all of the above for you.
saying that you want to check out a new branch:
------------
-git checkout -b mybranch
+$ git checkout -b mybranch
------------
will create a new branch based at the current `HEAD` position, and switch
In other words, if you have an earlier tag or branch, you'd just do
------------
-git checkout -b mybranch earlier-commit
+$ git checkout -b mybranch earlier-commit
------------
and it would create the new branch `mybranch` at the earlier commit,
You can always just jump back to your original `master` branch by doing
------------
-git checkout master
+$ git checkout master
------------
(or any other branch-name, for that matter) and if you forget which
branch you happen to be on, a simple
------------
-ls -l .git/HEAD
+$ ls -l .git/HEAD
------------
will tell you where it's pointing (Note that on platforms with bad or no
symlink support, you have to execute
------------
-cat .git/HEAD
+$ cat .git/HEAD
------------
instead). To get the list of branches you have, you can say
------------
-git branch
+$ git branch
------------
which is nothing more than a simple script around `ls .git/refs/heads`.
checking it out and switching to it. If so, just use the command
------------
-git branch <branchname> [startingpoint]
+$ git branch <branchname> [startingpoint]
------------
which will simply _create_ the branch, but will not do anything further.
that branch, and do some work there.
------------------------------------------------
-git checkout mybranch
-echo "Work, work, work" >>hello
-git commit -m 'Some work.' hello
+$ git checkout mybranch
+$ echo "Work, work, work" >>hello
+$ git commit -m 'Some work.' hello
------------------------------------------------
Here, we just added another line to `hello`, and we used a shorthand for
to the master branch, and editing the same file differently there:
------------
-git checkout master
+$ git checkout master
------------
Here, take a moment to look at the contents of `hello`, and notice how they
hasn't happened in the `master` branch at all. Then do
------------
-echo "Play, play, play" >>hello
-echo "Lots of fun" >>example
-git commit -m 'Some fun.' hello example
+$ echo "Play, play, play" >>hello
+$ echo "Lots of fun" >>example
+$ git commit -m 'Some fun.' hello example
------------
since the master branch is obviously in a much better mood.
work done. Before we do that, let's introduce a cool graphical tool that
helps you view what's going on:
- gitk --all
+----------------
+$ gitk --all
+----------------
will show you graphically both of your branches (that's what the `\--all`
means: normally it will just show you your current `HEAD`) and their
to resolve and what the merge is all about:
------------
-git merge "Merge work in mybranch" HEAD mybranch
+$ git merge "Merge work in mybranch" HEAD mybranch
------------
where the first argument is going to be used as the commit message if
of it as it can automatically (which in this case is just merge the `example`
file, which had no differences in the `mybranch` branch), and say:
+----------------
Trying really trivial in-index merge...
fatal: Merge requires file-level merging
Nope.
ERROR: Merge conflict in hello.
fatal: merge program failed
Automatic merge failed/prevented; fix up by hand
+----------------
which is way too verbose, but it basically tells you that it failed the
really trivial merge ("Simple merge") and did an "Automatic merge"
and once you're happy with your manual merge, just do a
------------
-git commit hello
+$ git commit hello
------------
which will very loudly warn you that you're now committing a merge
resolve to get the "upstream changes" back to your branch.
------------
-git checkout mybranch
-git merge "Merge upstream changes." HEAD master
+$ git checkout mybranch
+$ git merge "Merge upstream changes." HEAD master
------------
This outputs something like this (the actual commit object names
would be different)
- Updating from ae3a2da... to a80b4aa....
- example | 1 +
- hello | 1 +
- 2 files changed, 2 insertions(+), 0 deletions(-)
+----------------
+Updating from ae3a2da... to a80b4aa....
+ example | 1 +
+ hello | 1 +
+ 2 files changed, 2 insertions(+), 0 deletions(-)
+----------------
Because your branch did not contain anything more than what are
already merged into the `master` branch, the resolve operation did
Fetching from a remote repository is done by, unsurprisingly,
`git fetch`:
- git fetch <remote-repository>
+----------------
+$ git fetch <remote-repository>
+----------------
One of the following transports can be used to name the
repository to download from:
transport, it finds out the set of objects the downstream side
lacks and transfers (close to) minimum set of objects.
-HTTP(s)::
+HTTP(S)::
`http://remote.machine/path/to/repo.git/`
+
HTTP and HTTPS transport are used only for downloading. They
immediately `resolve`, that it's called `git pull`, and you can
simply do
- git pull <remote-repository>
+----------------
+$ git pull <remote-repository>
+----------------
and optionally give a branch-name for the remote end as a second
argument.
directory, like this:
------------------------------------------------
-mkdir -p .git/remotes/
-cat >.git/remotes/linus <<\EOF
+$ mkdir -p .git/remotes/
+$ cat >.git/remotes/linus <<\EOF
URL: http://www.kernel.org/pub/scm/git/git.git/
EOF
------------------------------------------------
of a full URL, like this:
------------------------------------------------
-cat >.git/remotes/jgarzik <<\EOF
+$ cat >.git/remotes/jgarzik <<\EOF
URL: http://www.kernel.org/pub/scm/linux/git/jgarzik/
EOF
------------------------------------------------
an empty directory:
------------
-mkdir my-git.git
+$ mkdir my-git.git
------------
Then, make that directory into a git repository by running
`.git`, we do things slightly differently:
------------
-GIT_DIR=my-git.git git-init-db
+$ GIT_DIR=my-git.git git-init-db
------------
Make sure this directory is available for others you want your
there, run this command:
------------
-git push <public-host>:/path/to/my-git.git master
+
$ git push <public-host>:/path/to/my-git.git master
------------
This synchronizes your public repository to match the named
propagation to other publicly visible machines:
------------
-git push master.kernel.org:/pub/scm/git/git.git/
+$ git push master.kernel.org:/pub/scm/git/git.git/
------------
storage by "packing them together". The command
------------
-git repack
+$ git repack
------------
will do it for you. If you followed the tutorial examples, you
unpacked objects that are contained in the pack file anymore.
------------
-git prune-packed
+$ git prune-packed
------------
would remove them for you.
projects / git.git / commitdiff