Git is a Version Control Software that allows you to save and maintain a history of your work. You can also revert to previous stages of your history, and make multiple branches of that history for experimentation.
Git is great for projects that have multiple contributors, because the history of all contributions is transparent.
We recommend you to follow this guide and complete the first three tasks before following with the tutorial below. In this tutorial you're going to learn:
- How to install/configure git
- Git basics (diffs, commits, etc.)
- Basic git commands on the command-line
- How to edit files in a text editor
- How to work with Github
- How to use Github with a Visual Studio project
There will also be two collaboration exercises in C and Python. Let's get started!
Downloading and installating programs in Linux is very different from Windows and Mac. Every Linux distribution has a package manager that downloads programs and their dependencies from the central servers of your Linux distribution source and installs them where your system expects them to be.
Antergos and Manjaro are both children of Arch. This means that they share a lot of similarities, including package manager. Do the following in a terminal to get git:
pacman -S git
-S means sync and will download the package you are looking for
Mint, Ubuntu and ElementaryOS are the children/grandchildren of the very first Linux distribution, Debian, hence they all use the same packaging software. Do the following in a terminal to get git:
apt-get install git
These distributions also have graphical packaging software, but for now, let's get used to using the command line.
Git needs to know who you are. Enter the following two commands into your terminal to set your identity:
git config --global user.name "Your Name"
git config --global user.email "you@whatever.com"
Every committed change in git, is associated with a username. This will allow git users to know who makes the changes.
Make a Github account if you haven't already. Github is a website that hosts your code (your repositories) and allows collaborative coding. Users can comment on code, create issues, copy repositories, and merge their changes together.
The CSSS uses Github to store our documents. You can back up all of your future coding projects, including your coding assignments ,under CSSS in Github.
Q: But shadowy CSSS git tutorial narrator, why would I want to put all my code up on the internet? Won't people find my stuff and copy it?
A: Github has a student pack which gives you free access to various web services:
- Free Github Micro Account (5 Private repositories. No one else can see your code)
- $100 credit for DigitalOcean (Provides web hosting services). DigitalOcean's cheapest server costs $5/month. You can use the server for 20 months.
- Free
.medomain name for a year with Namecheap.
In the top-right corner of this page you should see a button
labeled Fork. Click on it.
You now have a copy of this repositories on your Github account. You can do whatever you want to it.
Forking generally has one of the following meanings:
- Copying a project's code and taking it in a new direction for philosophical/political reasons, or;
- Making a copy of a project on Github.
Open terminal. We're now going to clone the repository you just forked.
Cloning is the process of copying a remote repository (e.g. a repository on Github) to your machine.
Using cd (change directory), move to a directory you'd like
your clone to be in, then enter the following command:
git clone https://github.com/your-github-account/csss-git.git
Use ls and you should see the csss-git folder. It contains the
contents of the repository. You can the code in the csss-git folder.
Your Github code will not be affected unless you make a git push.
Thsi si a teriblee speld sentins.
Fix the sentence above in an editor of your choice. We
recommend emacs, vim, or Sublime Text. In particular,
emacs and vim run in the terminal. Since you're going to work a lot with these editors, you might as well get used to
them.
C refers to your control/ctrl button.
- Save a change:
C-x C-s - Leave emacs:
C-x C-c
In vim, you have to type i or a to enter Insert Mode before you
can type. i enters Insert Mode before the cursor, while a enters Insert Mode after
the cursor. Esc takes you back to the Normal Mode. You need to
be in Normal Mode to run the commands below:
- Save a change:
:w - Leave vim:
:q - Do both at once:
:wq - Leave without saving changes:
:q!
Use git diff to see what changes you've made since your last commit.
To track a new file that you've added to your project,
use git add thefilenamehere. Since README.md is already tracked
by the project, we can just use git commit -a, which commits
all the files you've changed.
git commit -a will open up an editor for you to write a commit
message in. Once you write and save the commit message, the commit
will be made.
Advice: Writing good commit messages is important. In future, you (or your coworkers) will love you for it. Here's an example of a terrible commit message:
commit 2e4c6df191cdb6597464122d05adae61c314e91f
Author: Colin Woodbury <colingw@gmail.com>
Date: Tue Sep 11 18:59:22 2012 +0900
Fixed a bug
What was the bug? Where was it? How did you fix it?
Here's a good commit message:
commit 71c26a15c9f2f763028e34c6ddde83b1763d93d0
Author: Colin Woodbury <colingw@gmail.com>
Date: Sat Jan 3 09:19:48 2015 -0800
(Aura1): Success code given when `--needed` finds nothing to do - fixes #299
- This is what pacman does, and is helpful for scripts.
- In fixing this I found more weird behaviour:
`pacman -S` gives 1 (bad) saying there's nothing to do.
`aura -A` gives 0 (good) saying nothing.
Here we see:
- The title describes new behaviour. -A github issue is referenced (and closed) by this commit.
- The reason for making the changes was mentioned in the message.
- Further problems can be addressed.
Now that you've made a commit, let's confirm it with
git log. You should see a list of all the recent commits,
with the one you just made at the top.
If you screwed up your latest commit message, you can change it
with git commit --amend.
Remember HEAD from Learn Git Branching? To completely delete the commit you just
made, here are two handy commands:
git reset --hard HEAD: Deletes all your current uncommitted changes.git reset --hard HEAD^: Deletes your latest commit.
Do the second one to kill your commit.
That's pretty much all we have to teach you right now. There's more of
course, but the info here is a good start. See the file COMPLETED.md? Add
your name and the date to it, and commit the change.
The commit you made is on your local machine. By Pushing, we can sync your Clone and your Fork.
git push origin master
Your new commit will then be on Github too.
The commit is now in your Fork, but it's not in the original repository you copied from. By making a Pull Request from your Fork, you can ask the maintainers of the original repository to merge your changes into the master project.
On your Fork's page on Github, there should be a Green button near the upper-left. Click on it, and hit Create Pull Request on the next page. This will create a new Issue in the main repository, where everyone can comment on your commits. The maintainers may ask you to make further changes before they merge.
Soon the csss-git repository maintainers will merge your commit
in, and you'll be remembered for having completed this tutorial.
The process explained above is how modern collaborative software development is done. By getting a handle on it now, you'll have a head-start in your co-op placements and other real job placements. Good luck!
If you have any questions, feel free to ask us! Click on "Issues" on the right and open a new issue.