Your first repository
All the commands will be typed in the terminal for Linux/Mac users. On Windows, use the git bash for those who installed the official msysgit from the Git website, or the git-shell if you installed the GitHub client.
We’ll be doing most of our Git actions with the command line tool. So
you’ll need to open up a terminal (aka a console). You’ll also need to
decide where to keep your Git repositories. In this course we use the
$ symbol as the terminal prompt when we want you to type
something. For example:
$ echo "Command lines are rad." Command lines are rad.
Means that you should type
echo "Command lines are rad.". You don’t
need to type the
Now, where should you keep your code? I use a Linux machine, so I have
a home directory
/home/steven for all my files. When I’m developing
I like to keep repositories under the
dev directory. So whenever I
want to create a new repository, I use
cd /home/steven/dev to change
to my development directory. When I develop on OSX, the directory I
/Users/steven/dev. On Windows, it’s something like
C:\Documents and Settings\Users\Steven\dev.
Once you have your terminal open and you have changed to your development directory it is time to initialise your first Git repository:
$ git init myfirstrepo Initialized empty Git repository in /home/steven/dev/myfirstrepo/.git/
Git creates a directory called
myfirstrepo. This is where you’ll be keeping all
your code. Then Git creates a subdirectory called
.git which is where it keeps
all the settings and history for this repository. It starts with a dot, which means
that it is a hidden directory, to keep it out of the way of your files.
So at the moment, you have a completely blank repository that is ready to add
files. From now on, your command line will need to be inside
that Git knows which repository to use. The
status command in Git will let you
know the current status of your repository:
$ cd myfirstrepo $ git status # On branch master # # Initial commit # nothing to commit (create/copy files and use "git add" to track)
Add a file
We can put any type of file into Git. It is especially good at keeping track of
README, which is used to tell people what the repository is about.
Create a new file called
myfirstrepo/ with your text editor.
You can put any text inside here. Maybe you would like something a little
mysterious? We could put some Keats in here:
Here will I kneel, for thou redeemed hast My life from too thin breathing: gone and past Are cloudy phantasms. Caverns lone, farewel! And air of visions, and the monstrous swell Of visionary seas! No, never more Shall airy voices cheat me to the shore Of tangled wonder, breathless and aghast.
Yes, this seems suitable.
Once you have the file saved then it’s time to add it to your repository. In
Git, you add and remove files with the
$ git status # On branch master # # Initial commit # # Untracked files: # (use "git add <file>..." to include in what will be committed) # # README nothing added to commit but untracked files present (use "git add" to track)
Here Git is saying that the
README file is not being tracked. Let’s add it.
$ git add README $ git status # On branch master # # Initial commit # # Changes to be committed: # (use "git rm --cached <file>..." to unstage) # # new file: README #
Ok, it’s in. Now we can perform our first commit. A commit is a
snapshot of the repository at a particular point in time. Everything
we have added using the
add command will be saved in the commit. If
you have changed the
README since using
add then you will need to
add it again.
For now we just want the new
README file in our commit. So let’s
$ git commit -m "This is my first commit." [master (root-commit) 199b7a1] This is my first commit. 1 file changed, 7 insertions(+) create mode 100644 README
log will tell us that the commit is now in the repository:
$ git log commit 199b7a1457ebd5c1df3cb5fde21a45b769d9c31c Author: Steven Farlie <email@example.com> Date: Mon Oct 15 15:01:26 2012 +0200 This is my first commit.
Git has saved a snapshot of your repository at the moment you committed. If you
will take a look at
git status it will tell you that your directory is
currently ‘clean’, meaning that nothing has changed since the commit. You can
always return your directory back to any commit in your history. Likewise, you
can also fast-forward your directory to commits in your future, for example when
somebody has made a change that you would like to add to your repository. But
we’ll get to that later when we discuss pulling changes from others.
You can add more and more commits to your repository using the same
“add then commit” workflow. Try adding an attribution to the
(it’s John Keats from the poem
Endymion), or adding some
source files of your own to the repository, and committing a few
changes here and there.
Commits are on branches
In the example, you may have noticed the word
times. In Git, commits are organised into branches. The branch
master is the default branch name for a new Git repository. You can
think of branches as timelines of changes.
At the moment, your repository is very simple. There is just a single
commit, and the
master branch is a label that points to it. Like so:
o <-- master
Now say you have made some more changes. Like before you’ll use
commit to create a new commit. Git knows you are on the
branch, so it looks at the commit
master points to, adds your commit
to it, and points
master to your new commit. Now you have two
commits in your repository, and the
master branch points to the
o <-- master | o
There isn’t anything special about a
branch. It is just a label that
we add to the latest commit you made. It’s a much easier way than
typing out the identifier of the commit, which is a crazy-long unique
We won’t be getting too deep into this today, but branches become very
useful in day-to-day use by teams, as they allow you to experiment
with topic branches. It’s like fan-fiction for developers! You can
make a branch off the official
master branch, then if people like
them you can
merge the branch back into
master. Git is very smart
about merging changes, making it very easy to use once you get the
hang of it.
It can get very complicated over time, when a project might have at least a dozen active branches at any one time. But Git is very good at managing lots of branches. Even the Git project itself has gotten a little crazy at times with the number of branches!
Pushing to GitHub
Now that we have this fantastic local repository, it’s time to change the world by sharing it on GitHub!
Fortunately, the process is pretty simple. We’ll create a repository on GitHub
using the exact same name, then
push our repository to GitHub. At
the end we will have two repositories: the one on your computer, and
the one at GitHub.
- Create a repository called ‘myfirstrepo’ on the new repository page. Leave all the options as default.
Now, on that web page, see the section Push an existing repository from the command line. It has the two key commands you’ll need, tailored for your repository.
git remote addassociates your local repository to your GitHub repository, which will be called origin (which is a Git convention for the default remote repository). You could also call it github or upstream or anything you like, as it only applies to your local repository.
git pushpushes commits to origin (GitHub) from the branch master (the default branch). Then the
-uoption tells Git that we want to push to a branch called master on the remote repository called origin as the default in future, so we don’t have to type it every time. Our local and remote master branches are now linked.
Streamlining the process
Now that you’ve done it the manual way, you should know that it can be a little
easier than this. If you know at the beginning that you want to share your code
on GitHub, you can just create a new repository, check
“Initialize this repository with a README” and
clone the repository, like so:
$ git clone firstname.lastname@example.org:stevenfarlie/myfirstrepo.git Cloning into 'myfirstrepo'... remote: Counting objects: 3, done. remote: Compressing objects: 100% (2/2), done. remote: Total 3 (delta 0), reused 3 (delta 0) Receiving objects: 100% (3/3), done.
Everything will be set up for you, with an initial
README commit and origin
pointing to GitHub. If you use a graphical tool like GitHub for Mac it can be
even easier, as it will put a “Clone” button directly on GitHub website so you
don’t even have to type
git clone. These are all shortcuts for the same basic
process that you went through.