Version Control and Github

Why is version control important?

Why is version control important?

  • Keep track of changes in your code
  • Making changes with confidence, and even reverting when needed
  • Relying on source control as the communication medium for your team
  • Easily deploying different versions of your code
  • Understanding who made a change and when it happened

Concepts

Concepts - Tracking changes

A version control is mostly based around one concept:

Tracking changes that happen within directories or files

In most cases

  • Specify which files/directories to keep track of
  • The set of files or directories under version control are called a repository

Concepts - Committing

As you work with your files that are under version control, each change is tracked automatically!

  • This can include:
    • Modifying a file
    • Deleting a file
    • Adding files to repository
    • Moving files
    • etc ...

After each of these changes, you need to commit your changes

Concepts - Getting updates

As members of your team commit changes, it is important that you have the latest version → Reduces chance of conflict

You would need to do a git pull to update.

Concepts - Diffing (or viewing the differences)

Since each commit is recorded as a change of a file or set of files, it is sometimes useful to view what changed between revisions.

Most versions controls let you compare two files to see which lines of code changed!

Concepts - Branching

If you want experiment with code that could break your repository, you could create a branch.

git_branch

https://guides.github.com/introduction/flow/

Concepts - Types of Version Control - Centralized

It works in a client-server relationship. It's easy to understand and your have more control over users and access

git_branch

http://guides.beanstalkapp.com/version-control/intro-to-version-control.html

Concepts - Types of Version Control - Distributed

More powerful and detailed change tracking → less conflicts! No server is necessary.

git_branch

http://guides.beanstalkapp.com/version-control/intro-to-version-control.html

Git commands

Git commands

Tipically, the git flow is:

  • git init - Initialized repository
  • git add - Adds files and directories to repo
  • git commit - Commits your changes
  • git push - Push to your remote repository

There are other commands like: git clone, git merge, git status, git branch, git checkout , git pull and many more!

Git and Github

Git and Github

  • Github is the platform that many people use to host their repositories.
  • This repository is hosted on Github!
  • You can use this along with the cookiecutter Project template

Steps to create a repository

  • Create a username and password
  • Click on New repository"
  • Fill in the details like name of repository, privacy settings, etc.
  • To clone it locally, go to the directory (that will host the repository) using the Terminal
  • Copy and paste the commands on the screen to your Terminal window
  • And now you have a local copy of your repository!!

Exercise

Create a project repository on Github and clone it onto your computer

  • Author - Your name
  • License - MIT
  • Project name - 2018_Bootcamp_Github_repo

Github SSH Keys

Github SSH Keys

Now you will want to create SSH keys for your Github account

  • First you need to create your key:

                        $ cd ~/.ssh
                        $ ssh-keygen -t rsa -b 4096 -C "your_email@example.com"
                        $ Generating public/private rsa key pair.
                        Enter file in which to save the key (/Users/calder/.ssh/id_rsa): github_key
                        Enter passphrase (empty for no passphrase):
                        Enter same passphrase again:
                        $ ls
                        github_key
                        github_key.pub
                        $ chmod 600 github_key*
                        $ mv github_key ssh_keys/
                        $ mv github_key.pub pub_keys

Github SSH Keys

  • Now open ~/.ssh/config

                        open ~/.ssh/config

and add this to the file


                        ## Connects to Github
                        Host github.com
                        HostName github.com
                        User git
                        IdentityFile ~/.ssh/ssh_keys/github_key
                        IdentitiesOnly yes
                        PreferredAuthentications publickey

Github SSH Keys

Follow the instructions on:
https://help.github.com/articles/connecting-to-github-with-ssh/ 


                        ls -al ~/.ssh
                        eval "$(ssh-agent -s)"
                        ssh-add ~/.ssh/ssh_keys/* # or ssh-add -K ~/.ssh/id_rsa if in Mac

And now test your connection


                        # Attempts to ssh to GitHub
                        ssh -T git@github.com
                        
                        ## You should see something like this
                        The authenticity of host 'github.com (IP ADDRESS)' can't be established.
                        RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
                        Are you sure you want to continue connecting (yes/no)?
                        ## You should see this
                        Hi username! You've successfully authenticated, but GitHub does not
                        provide shell access.

You are now able to use git and Github!!

Back to main website:

https://tinyurl.com/bcb18