344 lines
14 KiB
HTML
344 lines
14 KiB
HTML
---
|
|
layout: reference
|
|
---
|
|
|
|
<div class="box">
|
|
<h2>
|
|
<span class="docs">
|
|
<a target="new" href="http://progit.org/book">book</a>
|
|
</span>
|
|
Sharing and Updating Projects
|
|
</h2>
|
|
<div class="block">
|
|
<p>
|
|
Git doesn't have a central server like Subversion. All of the commands
|
|
so far have been done locally, just updating a local database.
|
|
To collaborate with other developers in Git, you have to put all that
|
|
data on a server that the other developers have access to. The way Git
|
|
does this is to syncronize your data with another repository. There
|
|
is no real difference between a server and a client - a Git repository
|
|
is a Git repository and you can syncronize between any two easily.
|
|
</p>
|
|
|
|
<p>Once you have a Git repository, either one that you set up on your
|
|
own server, or one hosted someplace like GitHub, you can tell Git to
|
|
either push any data that you have that is not in the remote repository
|
|
up, or you can ask Git to fetch differences down from the other repo.
|
|
</p>
|
|
|
|
<p>You can do this any time you are online, it does not have to correspond
|
|
with a <code>commit</code> or anything else. Generally you will do a
|
|
number of commits locally, then fetch data from the online shared repository
|
|
you cloned the project from to get up to date, merge any new work into the
|
|
stuff you did, then push your changes back up.</p>
|
|
|
|
<p class="nutshell">
|
|
<b>In a nutshell</b> you can update your project with <code>git fetch</code>
|
|
and share your changes with <code>git push</code>. You can manage your
|
|
remote repositories with <code>git remote</code>.
|
|
</p>
|
|
</div>
|
|
</div>
|
|
|
|
<div class="box">
|
|
<h2>
|
|
<span class="docs">
|
|
<a target="new" href="http://www.kernel.org/pub/software/scm/git/docs/git-remote.html">docs</a>
|
|
<a target="new" href="http://progit.org/book/">book</a>
|
|
</span>
|
|
<a name="push">git remote</a>
|
|
<span class="desc">list, add and delete remote repository aliases</span>
|
|
</h2>
|
|
|
|
<div class="block">
|
|
|
|
<p>Unline centralized version control systems that have a client that is
|
|
very different from a server, Git repositories are all basically equal and
|
|
you simply syncronize between them. This makes it easy to have more than
|
|
one remote repository - you can have some that you have read-only access to
|
|
and others that you can write to as well.</p>
|
|
|
|
<p>So that you don't have to use the full URL of a remote repository every
|
|
time you want to syncronize with it, Git stores an alias or nickname for
|
|
each remote repository URL you are interested in. You use the
|
|
<code>git remote</code> command to manage this list of remote repos that
|
|
you care about.</p>
|
|
|
|
<h4>
|
|
git remote
|
|
<small>list your remote aliases</small>
|
|
</h4>
|
|
|
|
<p>Without any arguments, Git will simply show you the remote repository
|
|
aliases that it has stored. By default, if you cloned the project (as
|
|
opposed to creating a new one locally), Git will automatically add the
|
|
URL of the repository that you cloned from under the name 'origin'. If
|
|
you run the command with the <code>-v</code> option, you can see the
|
|
actual URL for each alias.</p>
|
|
|
|
<pre>
|
|
<b>$ git remote</b>
|
|
origin
|
|
<b>$ git remote -v</b>
|
|
origin git@github.com:schacon/git-reference.git (fetch)
|
|
origin git@github.com:schacon/git-reference.git (push)
|
|
</pre>
|
|
|
|
<p>You see the URL there twice because Git allows you to have different
|
|
push and fetch URLs for each remote in case you want to use different
|
|
protocols for reads and writes.</p>
|
|
|
|
<h4>
|
|
git remote add
|
|
<small>add a new remote repository of your project</small>
|
|
</h4>
|
|
|
|
<p>If you want to share a locally created repository, or you want to take
|
|
contributions from someone elses repository - if you want to interact in
|
|
any way with a new repository, it's generally easiest to add it as a remote.
|
|
You do that by running <code>git remote add [alias] [url]</code>. That
|
|
adds <code>[url]</code> under a local remote named <code>[alias]</code>.</p>
|
|
|
|
<p>For example, if we want to share our Hello World program with the world,
|
|
we can create a new repository on a server (I'll use GitHub as an example),
|
|
which should give you a URL, in this case "git@github.com:schacon/hw.git".
|
|
To add that to our project so we can push to it and fetch updates from it
|
|
we would do this:</p>
|
|
|
|
<pre>
|
|
<b>$ git remote</b>
|
|
<b>$ git remote add github git@github.com:schacon/hw.git</b>
|
|
<b>$ git remote -v</b>
|
|
github git@github.com:schacon/hw.git (fetch)
|
|
github git@github.com:schacon/hw.git (push)
|
|
</pre>
|
|
|
|
<p>Like the branch naming, remote alias names are arbitrary - just as 'master'
|
|
has no special meaning but is widely used because <code>git init</code>
|
|
sets it up by default, 'origin' is often used as a remote name because
|
|
<code>git clone</code> sets it up by default as the cloned-from URL. In
|
|
this case I've decided to name my remote 'github', but I could have really
|
|
named it just about anything.
|
|
</p>
|
|
|
|
<h4>
|
|
git remote rm
|
|
<small>removing an existing remote alias</small>
|
|
</h4>
|
|
|
|
<p>Git addeth and Git taketh away. If you need to remove a remote - you are
|
|
not using it anymore, the project is gone, etc - you can remove it with
|
|
<code>git remote rm [alias]</code>.</p>
|
|
|
|
<pre>
|
|
<b>$ git remote -v</b>
|
|
github git@github.com:schacon/hw.git (fetch)
|
|
github git@github.com:schacon/hw.git (push)
|
|
<b>$ git remote add origin git://github.com/pjhyett/hw.git</b>
|
|
<b>$ git remote -v</b>
|
|
github git@github.com:schacon/hw.git (fetch)
|
|
github git@github.com:schacon/hw.git (push)
|
|
origin git://github.com/pjhyett/hw.git (fetch)
|
|
origin git://github.com/pjhyett/hw.git (push)
|
|
<b>$ git remote rm origin</b>
|
|
<b>$ git remote -v</b>
|
|
github git@github.com:schacon/hw.git (fetch)
|
|
github git@github.com:schacon/hw.git (push)
|
|
</pre>
|
|
|
|
<p class="nutshell">
|
|
<b>In a nutshell</b> with <code>git remote</code> you can list our
|
|
remote repositories and whatever URL
|
|
that repository is using. You can use <code>git remote add</code> to
|
|
add new remotes and <code>git remote rm</code> to delete existing ones.
|
|
</p>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
<div class="box">
|
|
<h2>
|
|
<span class="docs">
|
|
<a target="new" href="http://www.kernel.org/pub/software/scm/git/docs/git-fetch.html">docs</a>
|
|
<a target="new" href="http://progit.org/book/">book</a>
|
|
</span>
|
|
<a name="fetch">git fetch</a>
|
|
<span class="desc">download new branches and data from a remote repository</span>
|
|
</h2>
|
|
|
|
<br/>
|
|
|
|
<h2>
|
|
<span class="docs">
|
|
<a target="new" href="http://www.kernel.org/pub/software/scm/git/docs/git-pull.html">docs</a>
|
|
<a target="new" href="http://progit.org/book/">book</a>
|
|
</span>
|
|
<a name="pull">git pull</a>
|
|
<span class="desc">fetch from a remote repo and try to merge into the current branch</span>
|
|
</h2>
|
|
|
|
<div class="block">
|
|
|
|
<p>Git has two commands to update itself from a remote repository.
|
|
<code>git fetch</code> will syncronize you with another repo, pulling down any data
|
|
that you do not have locally and giving you bookmarks to where each branch on
|
|
that remote was when you syncronized. These are called "remote branches" and are
|
|
identical to local branches except that Git will not allow you to check them out -
|
|
however, you can merge from them, diff them to other branches, run history logs on
|
|
them, etc. You do all of that stuff locally after you syncronize.
|
|
</p>
|
|
|
|
<p>The second command that will fetch down new data from a remote server is
|
|
<code>git pull</code>. This command will basically run a <code>git fetch</code>
|
|
immediately follwed by a <code>git merge</code> of the branch on that remote
|
|
that is tracked by whatever branch you are currently in. I personally don't much
|
|
like this command - I prefer running <code>fetch</code> and <code>merge</code>
|
|
seperately. Less magic, less problems. However, if you like this idea, you
|
|
can read about it in more detail in the.
|
|
<a target="new" href="http://www.kernel.org/pub/software/scm/git/docs/git-pull.html">official docs</a>.
|
|
</p>
|
|
|
|
<p>Assuming you have a remote all set up and you want to pull in updates, you
|
|
would first run <code>git fetch [alias]</code> to tell Git to fetch down all the
|
|
data it has that you do not, then you would run <code>git merge [alias]/[branch]</code>
|
|
to merge into your current branch anything new you see on the server
|
|
(like if someone else has pushed in the meantime). So, if I were working on my
|
|
Hello World project with several other people and I wanted to bring in any changes
|
|
that had been pushed since I last connected, I would do something like this:</p>
|
|
|
|
<pre>
|
|
<b>$ git fetch github</b>
|
|
remote: Counting objects: 4006, done.
|
|
remote: Compressing objects: 100% (1322/1322), done.
|
|
remote: Total 2783 (delta 1526), reused 2587 (delta 1387)
|
|
Receiving objects: 100% (2783/2783), 1.23 MiB | 10 KiB/s, done.
|
|
Resolving deltas: 100% (1526/1526), completed with 387 local objects.
|
|
From github.com:schacon/hw
|
|
8e29b09..c7c5a10 master -> github/master
|
|
0709fdc..d4ccf73 c-langs -> github/c-langs
|
|
6684f82..ae06d2b java -> github/java
|
|
* [new branch] ada -> github/ada
|
|
* [new branch] lisp -> github/lisp
|
|
</pre>
|
|
|
|
<p>I can see that since the last time I synchronized with this remote, five branches
|
|
have been added or updated. The 'ada' and 'lisp' branches are new, where the
|
|
'master', 'c-langs' and 'java' branches have been updated. In this case, my team
|
|
is pushing proposed updates to remote branches for review before they're merged
|
|
into 'master'.
|
|
</p>
|
|
|
|
<p>You can see the mapping that Git makes. The 'master' branch on the remote
|
|
repository becomes a branch named 'github/master' locally. That way now I can
|
|
merge the 'master' branch on that remote into my local 'master' branch by running
|
|
<code>git merge github/master</code>. Or, I can see what new commits are on that
|
|
branch by running <code>git log github/master ^master</code>. If your remote
|
|
is named 'origin' it would be <code>origin/master</code> instead. Almost any
|
|
command you would run using local branches you can use remote branches with too.
|
|
</p>
|
|
|
|
<p>If you have more than one remote repository, you can either fetch from specific
|
|
ones by running <code>git fetch [alias]</code> or you can tell Git to syncronize
|
|
with all of your remotes by running <code>git fetch --all</code>.
|
|
|
|
<p class="nutshell">
|
|
<b>In a nutshell</b> you run <code>git fetch [alias]</code> to syncronize your
|
|
repository with a remote repository, fetching all the data it has that you do
|
|
not into branch references locally for merging and whatnot.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
<div class="box">
|
|
<h2>
|
|
<span class="docs">
|
|
<a target="new" href="http://www.kernel.org/pub/software/scm/git/docs/git-push.html">docs</a>
|
|
<a target="new" href="http://progit.org/book/">book</a>
|
|
</span>
|
|
<a name="push">git push</a>
|
|
<span class="desc">push your new branches and data to a remote repository</span>
|
|
</h2>
|
|
|
|
<div class="block">
|
|
<p>To share the cool commits you've done with others, you need to push your
|
|
changes to the remote repository. To do this, you run
|
|
<code>git push [alias] [branch]</code> which will attempt to make your [branch]
|
|
the new [branch] on the [alias] remote. Let's try it by initially pushing
|
|
our 'master' branch to the new 'github' remote we created earlier.</p>
|
|
|
|
<pre>
|
|
<b>$ git push github master</b>
|
|
Counting objects: 25, done.
|
|
Delta compression using up to 2 threads.
|
|
Compressing objects: 100% (25/25), done.
|
|
Writing objects: 100% (25/25), 2.43 KiB, done.
|
|
Total 25 (delta 4), reused 0 (delta 0)
|
|
To git@github.com:schacon/hw.git
|
|
* [new branch] master -> master
|
|
</pre>
|
|
|
|
<p>Pretty easy. Now if someone clones that repository they will get exactly
|
|
what I have committed and all of it's history.</p>
|
|
|
|
<p>What if I have a topic branch like the 'erlang' branch we created earlier
|
|
and I just want to share that? You can just push that branch instead.
|
|
|
|
<pre>
|
|
<b>$ git push github erlang</b>
|
|
Counting objects: 7, done.
|
|
Delta compression using up to 2 threads.
|
|
Compressing objects: 100% (6/6), done.
|
|
Writing objects: 100% (6/6), 652 bytes, done.
|
|
Total 6 (delta 1), reused 0 (delta 0)
|
|
To git@github.com:schacon/hw.git
|
|
* [new branch] erlang -> erlang
|
|
</pre>
|
|
|
|
<p>Now when people clone or fetch from that repository, they'll get a 'erlang'
|
|
branch they can look at and merge from. You can push any branch to any
|
|
remote repository that you have write access to in this way. If your branch
|
|
is already on the server, it will try to update it, if it is not, Git will
|
|
add it.</p>
|
|
|
|
<p>The last major issue you run into with pushing to remote branches is the
|
|
case of someone pushing in the meantime. If you and another developer clone
|
|
at the same time, you both do commits, then she pushes and then you try to
|
|
push, Git will by default not allow you to overwrite her changes. Instead,
|
|
it basically runs <code>git log</code> on the branch you're trying to push and
|
|
makes sure it can see the current tip of the servers branch in your pushes
|
|
history. If it can't see what is on the server in your history, it concludes
|
|
that you are out of date and will reject your push. You will rightly have to
|
|
fetch, merge then push again - which makes sure you take her changes into
|
|
account.</p>
|
|
|
|
<p>This is what happens when you try to push a branch to a remote branch
|
|
that has been updated in the meantime:</p>
|
|
|
|
<pre>
|
|
<b>$ git push github master</b>
|
|
To git@github.com:schacon/hw.git
|
|
! [rejected] master -> master (non-fast-forward)
|
|
error: failed to push some refs to 'git@github.com:schacon/hw.git'
|
|
To prevent you from losing history, non-fast-forward updates were rejected
|
|
Merge the remote changes before pushing again. See the 'Note about
|
|
fast-forwards' section of 'git push --help' for details.
|
|
</pre>
|
|
|
|
<p>You can fix this by running <code>git fetch github; git merge github/master</code>
|
|
and then pushing again.
|
|
|
|
<p class="nutshell">
|
|
<b>In a nutshell</b> you run <code>git push [alias] [branch]</code> to update a
|
|
remote repository with the changes you've made locally. It will take what your
|
|
[branch] looks like and push it to be [branch] on the remote, if possible. If
|
|
someone else has pushed since you last fetched and merged, the Git server will
|
|
deny your push until you are up to date.
|
|
</p>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
<p><a href="/inspect">On to Inspection and Comparison »</a></p>
|