Git and Github

What is Git?

Git is a version-control system for tracking changes in computer files and coordinating work on those files among multiple people. It is primarily used for source-code management in software development, but it can be used to keep track of changes in any set of files.

When developers create something (an app, for example), they make constant changes to the code, releasing new versions up to and after the first official (non-beta) release.

Git and Collaboration

Version control systems keep these revisions straight, storing the modifications in a central repository. This allows developers to easily collaborate, as they can download a new version of the software, make changes, and upload the newest revision. Every developer can see these new changes, download them, and contribute.

What is GitHub?

Github.com is where developers store their projects and network with like minded people. It provides a online platform to sync your code, visually track changes and collaborate with other developers. More information on features provided by github is here

Repository

A repository (usually abbreviated to “repo”) is a location where all the files for a particular project are stored. Each project has its own repo, and you can access it with a unique URL.

Beginners Guide

Create a Github account at https://github.com. Remember your usename and password. You will need is everytime you sync your local git repo with github.

Git and Github in a nutshell:

# Working locally
git status      # tell whats the current sync status of local repo

# Two-step commits
git pull        # Syncs your local repo
git push        # Syncs your remote repo

# Adding file to stage changes
git add [file1] [file2] [--all]

# Committing Changes 
git commit [file1] [file2] [--all]

Github Flow

Getting started with a github repo

Go to https://github.com and login.

Create a new repository (aka repo) with a name for the project. In this example we will use YOUR-REPOSITORY as you repo name. Replace this with you own project name.

Now on your local machine, go to the directory under which you want this git project

# clone the git repo you created
git clone https://github.com/YOUR-USERNAME/YOUR-REPOSITORY.git

# check local dir 
ls

# you should be able to see repo directory
# cd into this git project dir 
cd [YOUR-REPOSITORY]

# create files and folder 
# finish all your work.

# from within the project run 
git add --all

# now commit all the changes 
git commit --all        # you will be asked to write a message with each commit

# sync it with remote repository 
git push origin master

For first time push you will be asked for username and password. After you have finished push run the following to remember your credentials for future use. Or else you will be asked to enter password everytime you push this repo.

# to remember git crcedentials (user, password)
git config credential.helper store

# then run git pull 
git pull

First time git usage on a machine can ask you for commit username and email address with instructions of how to set them both. You will need to use the git config --global option to set them both

git config --global user.name "John Doe"
git config --global user.email johndoe@example.com

Now check online at https://github.com/YOUR-USERNAME/YOUR-REPOSITORY to see if the changes you made synced correctly.

Next time when when you start working on your project you should always pull before making any local changes. This will sync your local with remote and you will have the latest changes before you start.

Following this will allow you to work on multiple machines at the same time. Also multiple users can work on this at the same time.

Advanced usage - git branch

Some Examples:

GitHub and the command line:

For developers new to the command line, the GitHub Training team has put together a series of tutorials on Git commands to guide the way. Sometimes, a series of commands can paint a picture of how to use Git:

Example: Contribute to an existing repository

# download a repository on GitHub.com to our machine
git clone https://github.com/me/repo.git

# change into the `repo` directory
cd repo

# create a new branch to store any new changes
git branch my-branch

# switch to that branch (line of development)
git checkout my-branch

# make changes, for example, edit `file1.md` and `file2.md` using the text editor

# stage the changed files
git add file1.md file2.md

# take a snapshot of the staging area (anything that's been added)
git commit -m "my snapshot"

# push changes to github
git push --set-upstream origin my-branch

Example: Start a new repository and publish it to GitHub

First, you will need to create a new repository on GitHub. You can learn how to create a new repository in our Hello World guide. Do not initialize the repository with a README, .gitignore or License. This empty repository will await your code.

# create a new directory, and initialize it with git-specific functions
git init my-repo

# change into the `my-repo` directory
cd my-repo

# create the first file in the project
touch README.md

# git isn't aware of the file, stage it
git add README.md

# take a snapshot of the staging area
git commit -m "add README to initial commit"

# provide the path for the repository you created on github
git remote add origin https://github.com/YOUR-USERNAME/YOUR-REPOSITORY.git

# push changes to github
git push --set-upstream origin master
Example: contribute to an existing branch on GitHub
# assumption: a project called `repo` already exists on the machine, and a new branch has been pushed to GitHub.com since the last time changes were made locally

# change into the `repo` directory
cd repo

# update all remote tracking branches, and the currently checked out branch
git pull

# change into the existing branch called `feature-a`
git checkout feature-a

# make changes, for example, edit `file1.md` using the text editor

# stage the changed file
git add file1.md

# take a snapshot of the staging area
git commit -m "edit file1"

# push changes to github
git push

References

Git

Guide: http://rogerdudler.github.io/git-guide/
Tutorial: https://git-scm.com/docs/gittutorial
Video: https://www.youtube.com/watch?v=noZnOSpcjYY

Github