Git

Git is a distributed version control system, like Mercurial.

At some stage, someone might put up a full tutorial showing how to use git, but for now, here's a badly written and terribly phrased guide on how to get and use a repository on redbrick's git hosting area. git.redbrick.dcu.ie is alive again.

Getting a git repository on Redbrick

`Redbrick hosts git repositories for users. You (and any other users you want) can have write access to the repositories. The world has read-only access via the web interface at [[1]]. It's perfect for any small open source projects you feel like starting, or if you want to branch/fork an existing open source project that's hosted on git.

Can I have a private repository that the world can't see?

Yes any repository can be public or private.

Can I use this to host my third year/fourth year/other important college project?

Short answer: No. And you shouldn't do this in your redbrick home directory either. There have been a number of times in the past where Redbrick has experienced problems meaning that a user who had the only copy (or the only backup copy) of a project weren't able to access it at some important deadline.

Long answer: If you have other copies of your code, and Redbrick isn't the primary (only) backup of it, and you just wanted to have yet another backup of it "just because", then maybe it might make sense to put it on redbrick. But I still wouldn't.

Creating an SSH key pair

Before you can use redbrick's git repositories from one of your computers (or from your redbrick shell), you need to create a public/private SSH keypair there if you haven't already. You'll need to do this for every device/place that you want to access git from. This might sound annoying, but it also lets you use git without having to type a password every time you need to clone/push/pull.

To do this on a Unixey (Linux/Mac OS X/on redbrick) system, run:

 ssh-keygen -t rsa

You'll probably want to hit enter for most/all of the default options. Especially the first one (where to save the key). When it's done, you'll probably see something like this:

[you@your-computer ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/you/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/you/.ssh/id_rsa.
Your public key has been saved in /Users/you/.ssh/id_rsa.pub.
The key fingerprint is:
58:06:86:0c:83:5e:4e:ab:75:93:96:37:76:42:73:07 you@your-computer.local
The key's randomart image is:
+--[ RSA 2048]----+
| .oo .o  E.      |
|.  +o. + . .     |
|. + . + = .      |
| . + * O .       |
|  o o = S        |
| .               |
|                 |
|                 |
|                 |
+-----------------+
[you@your-computer ~]$

(the little ascii art bit might not show up on older versions of SSH).

This has created two files on your computer - id_rsa and id_rsa.pub. id_rsa is your private SSH key, and id_rsa.pub is the corresponding public key. You keep id_rsa to yourself, and you can give id_rsa.pub to admins to allow you to access a repository. You can also upload it to a remote server (like redbrick) and put it in a specific location to allow you passwordless logins, but you can google for how to do that.

Create the repository

Once the admins have done their work, you need to actually create the repository. You do this on your own computer (or redbrick account, or wherever one of your keys came from). If you asked the admins to create you a repository named "awesomeproject", you'd do the following:

 mkdir awesomeproject
 cd awesomeproject
 git init
 git remote add origin git@git.redbrick.dcu.ie:awesomeproject.git
 

At this point you should do some work, like create a file and put something into it, or whatever. This is where a proper guide to git would be handy. Then commit your changes and do a first push:

 git commit -a -m "My first commit"
 git push origin master:refs/heads/master

Things to look out for: When you're doing the "git remote add origin" command, make sure you add ".git" to the end of the repository name. The system that redbrick uses (called Gitea, if anybody cares) to manage repositories needs that there. Also, in "git@git.redbrick.dcu.ie", the "git" user isn't a placeholder. You need use that user, not your own redbrick username.