(a gist based on the old toolmantim article on setting up remote repos)

To collaborate in a distributed development process you'll need to push code to remotely accessible repositories.

This is somewhat of a follow-up to the previous article "setting up a new rails app with git":http://toolmantim.com/article/2007/12/5/setting_up_a_new_rails_app_with_git.

h2. For the impatient

Set up the new bare repo on the server:

<pre><code class="shell">$ ssh myserver.com
Welcome to myserver.com!
$ mkdir /var/git/myapp.git && cd /var/git/myapp.git
$ git --bare init
Initialized empty Git repository in /var/git/myapp.git
$ exit
Bye!
</code></pre>

Add the remote repository to your existing local git repo and push:

<pre><code class="shell">$ cd ~/Sites/myapp
$ git remote add origin user@myserver.com:/var/git/myapp.git
$ git push origin master</code></pre>

Set the local master branch to track the remote branch.

Read further for a step-by-step explanation of what's going on.

h2. Pre-flight sanity check

Setting up a remote repository is fairly simple but somewhat confusing at first. Firstly, let's check out what remote repositories are being tracked in our git repo:

<pre><code class="shell">$ cd ~/Sites/myapp
$ git remote</code></pre>

None. Looking good. Now let's list all the branches:

<pre><code class="shell">$ git branch -a
* master
</code></pre>

Just one branch, the master branch. Let's have a look at @.git/config@:

<pre><code class="shell">$ cat .git/config
[core]
        repositoryformatversion = 0
        filemode = true
        bare = false
        logallrefupdates = true</code></pre>

A pretty bare-minimum config file.

h2. Creating the bare remote repository

Before we can push our local master branch to a remote repository we need to create the remote repository. To do this we'll ssh in and create it on the server:

<pre><code class="shell">
$ ssh myserver.com
Welcome to myserver.com!
$ cd /var/git
$ mkdir myapp.git
$ cd myapp.git
$ git --bare init
Initialized empty Git repository in /var/git/myapp.git
$ exit
Bye!
</code></pre>

A short aside about what git means by <em>bare</em>: A default git repository assumes that you'll be using it as your working directory, so git stores the actual bare repository files in a @.git@ directory alongside all the project files. Remote repositories don't need copies of the files on the filesystem unlike working copies, all they need are the deltas and binary what-nots of the repository itself. This is what "bare" means to git. Just the repository itself.

h2. Adding the remote repository to our local git repository configuration

Now that we've created the remote repository we'll add it to our local repository as a remote server called "origin" using @git remote add@, which is just a nicer way of updating our config file for us:

<pre><code class="shell">
$ git remote add origin user@myserver.com:/var/git/myapp.git</code></pre>

Let's see what it added to the config file:

<pre><code>[core]
  repositoryformatversion = 0
  filemode = true
  bare = false
  logallrefupdates = true
[remote "origin"]
  url = user@myserver.com:/var/git/myapp.git
  fetch = +refs/heads/*:refs/remotes/origin/*</code></pre>

We now have a remote repository "origin" that will fetch all of its @refs/heads/*@ branches and store them in our local repo in @refs/remotes/origin/*@ when a @git fetch@ is performed.

h2. Pushing to the remote repository

The time has come to push our local master branch to the origin's master branch. We do that using the @git push <target> <local>@ command.

<pre><code class="shell">
$ git push origin master
updating 'refs/heads/master'
  from 0000000000000000000000000000000000000000
  to   b379203bc187c2926f44a71eca3f901321ea42c6
 Also local refs/remotes/origin/master
Generating pack...
Done counting 1374 objects.
Deltifying 1374 objects...
 100% (1374/1374) done
Writing 1374 objects...
 100% (1374/1374) done
Total 1374 (delta 89), reused 0 (delta 0)
refs/heads/master: 0000000000000000000000000000000000000000 -> b379203bc187c2926f44a71eca3f901321ea42c6
</code></pre>

and that's all, folks. Further pushes can be done by repeating the @git push@ command.

Now you can tell your co-conspirators to:

<pre><code class="shell">$ git clone user@myserver.com:/var/git/myapp.git</code></pre>

and push and pull to your heart's content.

h2. Track the remote branch

You can specify the default remote repository for pushing and pulling using git-branch's track option. You'd normally do this by specifying the @--track@ option when creating your local master branch, but as it already exists we'll just update the config manually like so:

<pre><code>[branch "master"]
  remote = origin
  merge = refs/heads/master
</code></pre>

Now you can simply @git push@ and @git pull@.

h2. Sharing the remote repository with the world

If you want to set it up as a public repository be sure to check out the Git manual's chapter on "public git repositories":http://www.kernel.org/pub/software/scm/git/docs/user-manual.html#public-repositories.

h2. Working with remote repository branches

@git remote show@ is used to inspect a remote repository. It goes and checks the remote repository to see what branches have been added and removed since the last @git fetch@.

Doing a @git remote show@ at the moment only shows us the remote repo's master branch which we pushed earlier:

<pre><code class="shell">$ git remote show origin
* remote origin
  URL: user@myserver.com:/var/git/myapp.git
  Tracked remote branches
    master</code></pre>

Let's create a new local git repository and push to a new branch on the remote repository. We can then use @git remote show@ to see the new remote branch, @git fetch@ to mirror it into our local repo and @git checkout --track -b@ to create a local branch to do some work on it.

We'll start by creating a new local repo and pushing some code to a new branch in the remote repository.

<pre><code class="shell">$ mkdir /tmp/other-git
$ cd /tmp/other-git
$ git init
Initialized empty Git repository in /tmp/other-git
$ git remote add origin user@myserver.com:/var/git/myapp.git
$ echo "Rails 2... woo" > afile
$ git add afile
$ git commit -m "Added afile"
Created initial commit 0ac9a74: Added afile
 1 files changed, 1 insertions(+), 0 deletions(-)
 create mode 100644 something
$ git push origin master:rails-2
updating 'refs/heads/rails-2' using 'refs/heads/master'
  from 0000000000000000000000000000000000000000
  to   0ac9a7457f4b21c9e058d4c54d262584bf35e528
 Also local refs/remotes/origin/rails-2
Generating pack...
Done counting 3 objects.
Deltifying 3 objects...
 100% (3/3) done
Writing 3 objects...
 100% (3/3) done
Total 3 (delta 0), reused 0 (delta 0)
Unpacking 3 objects...
 100% (3/3) done
refs/heads/rails-2: 0000000000000000000000000000000000000000 -> 0ac9a7457f4b21c9e058d4c54d262584bf35e528
</code></pre>

Now let's switch back to our old git repository and see if it detects the new branch on the remote repository:

<pre><code class="shell">$ git remote show origin
* remote origin
  URL: user@myserver.com:/var/git/myapp.git
  New remote branches (next fetch will store in remotes/origin)
    rails-2
  Tracked remote branches
    master
</code></pre>

Let's update our mirror of the remote repository by doing a @git fetch@:

<pre><code class="shell">$ git fetch
* refs/remotes/origin/master: storing branch 'rails-2' of user@myserver.com:/var/git/myapp.git
  commit: b379203
$ git remote show origin
* remote origin
  URL: user@myserver.com:/var/git/myapp.git
  Tracked remote branches
    master
    rails-2</code></pre>

We should now be able to see this in a our list of remote branches:

<pre><code class="shell">$ git branch -a
* master
origin/rails-2
origin/master</code></pre>

If we then wanted to do some work on this remote @rails-2@ branch we create a new local tracking branch like so:

<pre><code class="shell">$ git checkout --track -b rails-2 origin/rails-2
Branch rails-2 set up to track remote branch refs/remotes/origin/rails-2.
Switched to a new branch "rails-2"
</code></pre>

To keep up-to-date and push new changesets we simply use @git push@ and @git pull@ when working in the local @rails-2@ branch.

Also notice, like we manually changed for master, @.git/config@ has a new entry for this new tracking branch:

<pre><code>[branch "rails-2"]
  remote = origin
  merge = refs/heads/rails-2
</code></pre>

h2. Further Reading

"Sourcemage's Git Guide":http://wiki.sourcemage.org/Git_Guide has some very very handy real-life examples of git commands you'll often need.