This tutorial is targeted towards the students of courses at Founders & Coders. Feedback or Suggestions in the format of an issue or contributions as a pull request are appreciated.
As a student, if you get stuck at any point, please open an issue and I will try to get back to you as soon as possible. If you would prefer, feel free to contact me on Gitter. When the issue is solved, do think about making a pull request to the project.
The introduction to Git is aimed at the first week of the full time Founders & Coders course, or to those just starting out with git. The hope is that this introduction will cover all you need to know to start collaborating on code with your fellow teammates.
Git for Collaboration is aimed at the second week students of the course, or those that have mastered the first section. Even though most of the advice in this tutorial will take a while to digest - and practise is essential. A good goal is to understand all these concepts, and implement at least most of these tips in your collaborative projects before finishing your time as a student at Founders & Coders.
The introduction to Git is aimed at the first week of the full time Founders & Coders course, or to those just starting out with git. The hope is that this introduction will cover all you need to know to start collaborating on code with your fellow teammates.
Simply put, this is your project folder. This repository can be located locally (in your file system on your computer), or remotely (on Github). Either way, it is the same repository.
We will use Git for this. A way of keeping track of changes in the code which makes it possible to work with multiple developers on the same repo.
A version control system.
A remote location where you can store you code, and which all the members of the team have access to. Think of it like a dropbox for code. One of the big differences however is most repositories on github are public. Anybody can see your code.
A way of saving your code at different points along the project. Unlike many tools you may have used however, all commits are saved. This creates a project history and a way to track changes.
As you work on a git repo the first branch you are on is usually the default branch. This is often called master. If you start working on a section of the website (say the footer styling), it is best practise to create your own branch for that feature. Creating your own branch is like taking a copy of master and renaming it. When you commit, they will now be on that new branch only.
In the sections below we will walk through how to do this. For the meantime, just note that you always have one default branch, and can have as many other branches as needed.
Git can provide you with a complete history of every commit made on a project. Benefits include:
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Being able to see what differences to the file system you have made before you have commited.
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Being able to see what differences exist between commits
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Being able to move between different commits (or places in time). This is especially useful if something became broken while you were working on it, and you need to start again.
In the introduction section of this tutorial, we won't be able to cover all these benefits in practise extensively. However, we will aim to give you all the information you will need to know by the end.
Version control makes this possible. If you work on one file, and then I work on the same file at the same time when we want to combine our changes git allows us to keep both versions save that we can compare. This allows us to integrate our changes more swiftly.
We will practice with this later.
A good work flow with git always involves branching. Having branches helps organise the code, and keep track of who is working on what.
Before we begin, if you don't have a Github account, please get one.
Next please fork this repository.
On your local machine, please make sure you have git installed.
If you are using a mac, the easiest thing is to install git with Homebrew. Want to learn more about Homebrew? Check out this tutorial.
Windows use http://git-scm.com/download/win. and Linux install using these instructions http://git-scm.com/download/linux.
The next step is to clone the forked version of this repository. On the main page of the repo, copy the url shown here:
Then use the command in your terminal:
git clone https://github.com/NataliaLKB/learn-git-basics.git
You should now be ablle to redirect into the directory just created using the command line.
Next, it is good to get in the habit after each command to use git status. Let us use it now.
git status
Now check which branch you are on:
git branch
You should only see master which is the default branch in this repo.
When there are other branches in your repo the green branch is the current one you are on.
The next step is to create your own branch to work on. try this:
git branch new-branch
It is best to try to name your branches as specific as possible, so not to confuse them with any others. There are many naming conventions out there for branches, but for this week simply try to name them off of a feature. For example (navbar-collapse or sass-file-structure). To see all your branches:
git branch
As you can see, you have created your branch, but are not currently on it. To navigate onto it please:
git checkout new-branch
git branch
Now you can see you are on that branch. Go back to master and now we are going to delete new-branch.
git checkout master
git branch -d new-branch
git branch
As you can see, your branch is now gone.
Now it is time to make some changes in the project. Make yourself a new branch named update-cheatsheet and go onto it. open up the file cheatsheet.md in your favourite text editor.
As you can see, this contains all the commands you will need to begin using git. Continue to add to it all the new commands you learn. To begin, here is a command that both creates a branch, and moves you onto it at the same time:
git checkout -b <new branch name>
Add that command, and its description to cheatsheet.md and save it. Now in your terminal:
git status
You will see something like this:
You will see your changes in red. now we need to add them to the git staging area. Doing this is like telling git to pay attention to these files, and start tracking the changes. To do this write this command:
git add cheatsheet.md
git status
Now you can see the file name has turned green. Now to commit your changes.
git commit -m 'adding new command in the cheatsheet'
git status
The message could be anything, but it is best to make it something that describes what you just did. You can also use the command git commit without -m '<message', however beware that it will send you to a text editor called Vim. Though learning how to use Vim is important, it isn't necessary at this stage. Typing :q straight away will get you out of it and commit again with a message.
Now that you have made and committed your changes, it is time to merge your branch with master. Even though you are not working with anyone else on this repository, it is always good practice to make sure your current branch is completely up to date with master. Imagine if you were working with a team. Someone else has already pushed up changes to master. If that someone else and yourself have changed the same file, it is quite likely that your changes will not be compatible with theirs. To avoid this, you want to merge your changes with theirs to avoid future problems. Checkout back onto master and pull down. These commands look like this:
git checkout master
git pull origin master
Pulling down means that you are getting any recent changes from the remote master branch which is located in Github. Next go back to your branch (update-cheatsheet) and merge with master.
git merge master
Even though in this situation there isn't any changes to merge, it is best to get in the habit on going through these steps in your work flow. Merging like this means taking any possible changes in master and merging them with the branch you are currently on. After you merge with master you have to push your changes to the remote repo (Github).
git push origin update-cheatsheet
When you pull or push you are referring to your remote repo, or origin. In the example of git push origin <branch name> you are pushing your local changes to a remote branch that you are both creating, and naming. Since you are creating this branch from your local one it makes things much simpler if you use the same name for your remote branch, as your local one.
For more information on pushing, see here
Go to your browser and open up this repository in github. Press the branches button
And then make a pull request to master
Afterwards you will see a merge button. Press it and delete your branch. Now your remote branch master is completely up to date with your latest changes.
Return to your terminal and navigate to your local master branch. Pull down. You will see your branch update (fast-forward). Delete the branch update-cheatsheet.
Check all the branches on this repository, even the remote ones. To do this use this command:
git branch -a
You should see something like this:
Run the command:
git checkout merging-experiments
Open up the git cheatsheet, as you can see there are some differences between this and master. To see these differences use command:
git diff master
The differences in green and the additions on this branch, that don't exist on master. The red are the things that are on master, that don't exist on this branch.
Merge with master. You should have a git conflict that looks something like this:
Do you see the lines at the top. The first section is labelled HEAD those are from this branch. The next section is from master. Delete the lines, and any other code you want until the cheatsheet looks like how you want it to look.
Afterwards git status, add the files in red, commit, and push. Then make a pull request to master like before and merge. Don't forget to update your local master branch, and delete the merged branch in Github and in your local repo. It is good to keep your working environments clean and organised.
Github flow is what most teams at Founders & Coders follow. It is simple and effective.
For a visual guide, and some helpful tips: https://guides.github.com/introduction/flow/
To find out why Github uses Github flow: http://scottchacon.com/2011/08/31/github-flow.html
Git for Collaboration is aimed at the second week students of the course, or those that have mastered the first section. Even though most of the advice in this tutorial will take a while to digest - and practise is essential. A good goal is to understand all these concepts, and implement at least most of these tips in your collaborative projects before finishing your time as a student at Founders & Coders.
##### Commit Hash:
Simply put, the HEAD is a reference to a commit object. For more information see: http://eagain.net/articles/git-for-computer-scientists/
As discussed previously git stores all the commits on the project. You can use them as a timeline and travel back and forth in time. This section shows you a simple way of doing that which will come in handy as you work in projects with your team.
Before we start make sure you have a terminal open located at the local copy of this repo. The same one that was used for the first tutorial is essential. Make a new branch called timeline-practice and navigate onto it.
Make a new directory in the project via the command line. Lets call it time.
mkdir time
Also make a new file in that directory and call it whatever you like. A simple text file should be fine. After you are done, open it.
touch time/newfile.txt
open time/newfile.txt
Write the current time stamp, and a short message to your future self. Save it. Next add and commit your changes. Your commit message should be descriptive of what you just did. Repeat step 2 twice more, deleting the previous time and message, and adding the new time and a different message. Make sure you add and commit each time. Make sure your commit messages are unique, and you can tell which one was first, second, and third. Next type in this command:
git log
You should see something like this:
Pick the second time commit that you made and copy the hash. Use q to exit the log and checkout to your commit.
git checkout <commit hash>
git status
As you can see after you checkout a message appears informing your that you are in a 'detached HEAD' state, meaning your are not working on any current branch. Open up the file in the time folder and look at the time and message. It should be the 2nd one that you wrote.
Repeat step 6, and use the hash of the first time commit you made. Open the file and see that the time of your first commit, and your message to yourself. This is going back in time. You can easily go back as far as you like in the project and see older iterations of this tutorial!
Next, we should go back to the future. The quickest and easiest way is to checkout onto thetimeline-practise branch and you should be back up to date. However, you can also navigate back to the latest commit from where you are now. First, check git log. You will notice your latest commits are no longer on there. This is where another command is handy. git reflog is best used to find recently "lost" commits. you should see something like:
Find the commit name of the last commit you did (the third time that you recorded) and copy the short hash in yellow. Checkout back to that commit, and git diff timeline-practise there should be no difference.
Checkout back to timeline-practise and push up to Github to make a pull request to master. Make sure you first check that
it is up to date with master locally.
You should aim each commit to be a "safe" version of the project. This means that if you checkout to any commit in your timeline, that should reflect where the project was at that point, and be functional.
Given that, when you commit is very important. I have heard two very useful guidelines.
The first, is that a you complete the task assigned to you, you make several commits at different times during that task. In the end you merge all those commits together to make one very informative commit of that task. I will talk about ways to merge commits together in a later section.
The second method is you work through your task and complete it before adding or committing at all. Then you check the status of the repo and see all the files you have changed. The next step is selectively adding and committing
Through my research I have come across many different methodologies, and ultimately you should try to do what seems the most natural to you. I use both of these methodologies depending on the extend of the task before me. The best thing is to always keep in mind that you and your colleagues will inevitably need to go back to your commits and it will help everyone if commits are aptly named.
Likewise, even in pull requests, you must aim to make your commits a clear and concise summary of what tasks where completed on that branch. That way the person reviewing your pull request understands what they will be reviewing before looking at the code itself.
Just like choosing when to commit, and what to commit, it is also important to think about your naming. It is always good to be as descriptive as possible with your commit messages.
Also consider:
- Present tense for your commit messages
- If related to an issue on github, should contain issue number
- The first line should be 50 characters or less. Your message should be brief and to the point.
- Focus on why you did something, not how you did it
- Avoid
ands. If you find yourself wanting to writeand, you should probably break up that commit into multiple ones.
Remember that the purpose of this commit is to be a message for future you, or your colleagues who may not have known what you are working on. Try to think about your message with this in mind.
Many development teams take it one step further and turn their commit messages into change logs. These change logs may be used for user consumption making it all the more important to have clear messages of what was done for that commit.
I tend to favour one line commits for simplicity, but many schools of thought out there prefer multiline commit messages. For examples of "best practice" formats for this see:
Often you will find yourself wanting to merge commits, or organising your early commits slightly differently on a branch to better demonstrate what you worked on. I will briefly go through one easy way to do this.
This is my preferred method of merging commits together. It leaves you with lots of flexibility.
To begin, make a new branch and make some new files and commit regularly (at least twice).
Next git log and pick the 3rd most recent hash. Copy it and:
git reset --soft <commit hash>
git status
git log
Your working directory shouldn't changes, but all the files that you changed should be in green. Your log should have the newest commit as the hash you copied. Even though all your work is still the same as before the reset, the commits are different. Then you can commit again and this is an easy way to replace 2 or more commits with one commit.
For more information and techiques see:
- What to learn more about reset?
- Only want to ammend the previous commit?
- The Golden Rule of Rebasing
Have you found a useful Git or GitHub resource or tutorial? Please let us know by creating an issue
- For generating ssh keys https://help.github.com/articles/generating-ssh-keys/
- CodeSchool "Git Real" tutorial: http://gitreal.codeschool.com/
- Atlassian (makers of SourceTree) Git Tutorials: https://www.atlassian.com/git/tutorials/
- Git Branching: https://github.com/pcottle/learnGitBranching
- Interactive tutorial: http://gitimmersion.com
- Build Podcast (intro to Git) Video: http://build-podcast.com/git/
- Git User Manual: https://www.kernel.org/pub/software/scm/git/docs/user-manual.html
- GitHub's Treasure Trove of Video Tutorials: https://www.youtube.com/user/GitHubGuides (channel) and specifically: https://www.youtube.com/watch?v=FyfwLX4HAxM
- The simple guide to git: http://rogerdudler.github.io/git-guide/
- Jeff Schomay's Git-Fu presentation: http://slides.com/jschomay/git-fu
- Git Pretty: http://justinhileman.info/article/git-pretty/ (anything visual makes learning git much easier...)
- Intermediate: http://www.raywenderlich.com/74258/git-tutorial-intermediate
- Visualize your Git with SourceTree: http://www.sourcetreeapp.com/