Git/Repository on a USB stick

Instead of having to resort to a hosting company to store your central repository, or to rely on a central server or internet connection to contribute changes to a project, it's quite possible to use removable memory to exchange and update local repositories.

The basic steps are:

1. Mount the removable memory on a pre-determined path
2. Setup a bare repository in the removable memory
3. Add the repository in the removable memory as a remote

Throughout this article, it's assumed that the repository will be mounted in /media/repositories.

Starting from scratch

Let's assume a brand new project is being started, titled Foo. The people working on project Foo will use a removable memory device as a central repository for the whole project. For this reason, let's create a fresh repository in a USB stick.

To start off, instead of relying on a path name generated automatically by the OS, the USB stick will be mounted on a custom path. Let's assume the USB pen drive is located at /dev/sdb1, and the intended mount point is /media/repositories. Another important aspect is that the USB pen drive needs to be mounted with proper permissions, so that it doesn't cause problems within the repository. One way to avoid these issues is to mount the USB drive with your own user ID and group ID, which can be achieved through the following commands:

$ sudo mkdir /media/repositories
$ my_uid=`id -u`
$ my_gid=`id -g`
$ mount -o "uid=$my_uid,gid=$my_gid" /dev/sdb1 /media/repositories

Having mounted the USB drive on the desired path, let's create a bare repository.

$ cd /media/repositories
$ mkdir /media/repositories/foo
$ git init --bare /media/repositories/foo
Initialized empty Git repository in /media/repositories/foo

With this step, a repository has been created in the USB memory drive. Now, all that's left is to mount the USB pen on any computer on a specific path, clone the repository, and work away.

$ git clone /media/repositories/foo
Cloning into 'foo'...
warning: You appear to have cloned an empty repository.
done.

Done.

In case the mount point changes to another path (in some cases, auto-mounting does that), the repository's URL can be set through the following command:

$ git remote set-url origin file://<path to new mount point>

Pushing local repository to a USB stick

Let's assume you've been working on a project, and you already have a working git repository that you've been working on your desktop. Now, you've decided that want to keep track and update several concurrent versions of that repository without having to use a network connection. One possible solution is to start a Git repository on a USB key, and use that USB key as a centralized repository where everyone can push their contributions and update their local version.

To start a Git repository on a USB stick, first let's mount the USB stick on a selected path. This is achieved through the process described in the previous section.

$ sudo mkdir /media/repositories
$ my_uid=`id -u`
$ my_gid=`id -g`
$ mount -o "uid=$my_uid,gid=$my_gid" /dev/sdb1 /media/repositories

Let's assume that the project tree is located in ~/devel/foo. To start a repository on /media/repositories/foo, run the following command:

git clone --bare ~/devel/foo foo

That's it.

Now, you can clone the Git repository stored in the USB drive and continue working on your project.

$ git clone /media/repositories/foo/
Cloning into 'foo'...
done.

If you wish to add to your local repository the newly created USB repository as a remote repository,

$ git remote add usb file:///media/repositories/foo

To establish the master branch of the USB repository as the upstream branch of your local master branch, the contents of the newly added remote branch must be fetched and the upstream branch must be specified. This step is performed by applying the following commands:

$ git fetch usb
From file:///media/repositories/foo
 * [new branch]      master     -> usb/master
$ git branch --set-upstream-to=usb/master
Branch master set up to track remote branch master from usb.