I am going to bore you with...

  1. What is Open Source

  2. What is GitHub

  3. What is a Git Repository

  4. What is Forking and Cloning

  5. Setting up Git on your computer

  6. git add, git commit, git push

  7. git fetch, git merge, git branch

  8. Git Workflow

  9. Contribution guidelines

What is Open Source, Again?

  • Source Code is available(to mess with)

  • Generally, available to distribute 

  • may(may not) be free

Why Open Source turned out to be an instant love of every programmer?

I can do what I want.

I am SUPERMAN.

  • An open source software(application) can be modified according to one's needs

  • Learn how others are creating that application

  • Easy to be a part of an ongoing development work

  • Re-usable code

  • Generally Free to use

  • No need to wait for the organization in charge to make changes

  • Free of any Piracy

Why was it a hassle to contribute into Open Source?

"I am done with all these guys messing up with my code."

  • Managing code by thousands of contributors was almost impossible.

  • Following a proper development schedule was not easy.

  • Hard to find projects of your choice.

  • ...

Solution?

GitHub

GitHub makes it easier to...

  • make your code Open Source

  • manage literally any number of contributors

  • manage versions of your product

  • follow a well defined structure to complete the project

  • contribute into projects of your choice

  • find open source projects to work on

  • create an online portfolio of your skills

Why should I contribute?

  • To add the functionality you want

  • To get experience about any technology you have just learnt

  • To work with people from around the globe

  • To learn new things 

  • To get a feeling of a significant work

  • To get known by people in a community

  • To showcase your skills by working on real-world projects

Getting Your Hands Dirty...

Repository

A GitHub Repository is an online Folder at Github, which contains all of the files within a project.

GitHub allows any contributor to get notified about any changes in any file within a Repository.

A Repository in one account can be copied in another account using "Fork" Button.

A new Repository can be created by clicking on the the "+" button in Github Menu bar.

 

A GitHub Repository

Some well-know Repositories

  • Vlc - https://github.com/videolan/vlc

  • Ruby on Rails - https://github.com/rails/rails

  • facebook-ios-sdk - https://github.com/facebook/facebook-ios-sdk

  • ...

Git Structure

Remote Server(Github)

Local System (Your PC)

  • Github Profile

  • Online Repositories

  • Work Graph

  • Navigable code

  • Git bash(terminal)

  • Local copy of Git Repo

  • Edit files locally

  • Working branches

Git Bash

Provides a new "git" command within your Linux terminal or a separate command prompt kind of tool for windows and macs. 

Git can be downloaded from: http://git-scm.com/downloads

Git Installation

  • Linux(Ubuntu): sudo apt-get install git

  • Windows: http://git-scm.com/download/win

  • Mac: http://git-scm.com/download/mac

Setting up for first use

Open up your terminal and set up your user name, as

$ git config --global user.name "YOUR NAME"

Set up your e-mail address(the one you signed up with on github), as

$ git config --global user.email "YOUR EMAIL ADDRESS"

For Further Reference: https://help.github.com/articles/set-up-git

git clone

Clones a repo from Remote Server(Github Website) to your local machine(PC).

$ git clone "REPOSITORY CLONE ADDRESS"

For example, 

$ git clone https://github.com/smvdu/sfd-smvdu.git

Review

  1. What is Open Source

  2. What is Github

  3. What is a Repository

  4. Forking a Repo

  5. Cloning a Repo

How to edit cloned files?

How do you edit a text file?

By Using an Editor. No complicated stuff here.

 

eg. Sublime Text, gedit, vim, notepad, etc.

README File

  • Shouldmust be present in every github repo

  • Summary of the project

  • Basic setup information about the repo

  • Contribution guidelines

  • Workflow for this repo

git status

"git status" shows the modified files in cloned copy of repo on the local machine.

$ cd "REPO NAME"
$ git status
    on branch master
    Files modified:
        file1
        file2
        .
        .

git add

"git add" command is used to add modified files for committing.

$ git add --all

This will add all the modified files in the next commit.

.gitignore

Used to ignore the changes in certain files/directories.

 

"." marks this file as a hidden file. 

git commit

"git commit" will group together all the changes you have made with a meaningful message.

$ git commit -m "DESCRIPTION ABOUT MODIFICATIONS"

-m stands for commit message

Review

  1. cloned a repo using git clone

  2. made some modifications using a text editor

  3. checked for modified code using git status

  4. finalized files to be committed using git add

  5. committed added files using git commit

  6. README and .gitignore file

git branch

Branches in a git repo allows, even further copies of the same code.

 

Changes done in one branch do not affect the code in another branch, until done explicitly 

For any new task, create a new branch and later merge it with the parent branch. In this case new branch is "feature_x" and parent branch is "merge".

branching commands

To see all the branches in a repo

$ git branch

To create a new branch, from current branch

$ git branch "NEW_BRANCH NAME"

To move to another branch

$ git checkout "BRANCH_NAME"

git push

"git push" sends all the commits to the remote server(Github), from where you cloned your repo.

$ git push "REMOTE NAME" "BRANCH NAME" 
$ git push origin master

eg:

Pull Requests

Hey(Repo Owner), I have made some changes in this repo, can you add those up with the main repo? 

Pull Requests Sequence Flow

  1. Go to your forked repo on Github

  2. Click on "pull requests" on right hand side of the repo page

  3. Click on "new pull request"

  4. Add the title of the pull request

  5. Send the pull request

Your pull request will be merged by the "Repo Owner" with the parent repo(from where you forked it).

git fetch

"git fetch" gets the latest code from the parent repo and add it directly to your local repo.

$ git fetch "REMOTE NAME"

$ git merge "REMOTE NAME"/"BRANCH NAME"

Github Remotes

Github Remotes are like variables which have the values as the link to a particular repo on Github remote server.

$ git remote add upstream "REPO LINK"
$ git remote add upstream "https://github.com/smvdu/sfd-smvdu.git"

Now anytime when you run "git fetch upstream" it will check your local files against this repo.

git pull

"git pull" is similar to "git fetch", but it also runs "git merge" command by itself.

git pull will update all the branches in local repo. Whereas while using git fetch only listed branches will be updated.

$ git pull upstream

git merge

"git merge" merges two different copies of code.

Generally used for merging two different branches and code from upstream to local repo.

git merge usage

In branch context, 

$ git merge "BRANCH_NAME"

This will add the code from the "BRANCH_NAME" branch to the current branch. Code in any other branch will remain as it is.

If we are on master branch and wants to merge it with develop branch then run,

$ git merge develop

After running "git fetch" command. Fetched code is merged with one of the branches as, 

$ git merge "REMOTE NAME"/"LOCAL BRANCH NAME"

for example,

$ git fetch upstream develop
$ git merge upstream/develop

Here, fetch commands gets the code from develop branch of remote server and merges it with current branch.

merge-conflicts

  • Arise while using "git merge" command

  • When git can't decide by itself which code to be preserved

  • merge conflicts has to be removed by the programmer manually

  • There shouldn't be any merge conflicts before sending a Pull Request

<<<<<<<< HEAD
def func(a b):
=============
def func(x, y):
>>>>>>> refs/head/new_func

Review

  1. Git branching structure
  2. git push to push new changes on your forked repo
  3. Pull Requests to submit your changes to parent repo
  4. git fetch and git pull to update your local repo
  5. git merge to merge two different copies of code
  6. merge-conflicts and how to remove them

The Next LeveL

  • git init
  • git diff
  • git log
  • git rebase
  • git reset
  • git stash

Github Flow

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

Github Issues

  • Used to define and assign tasks to be completed

  • Used for any queries regarding the code

  • Used to report a bug or to give a suggestion

Git Network Graph

Contribution Workflow

  1. First of all fork the the repo and clone it to your local machine

  2. Run the code on your local machine

  3. Check out the issue page on Github for the repo

  4. Pick up one of the issue and start working on it

  5. Comment below on the issue if there is any doubt

  6. Every good repo on Github has a contribution guidelines link, go through it

  7. Start working on the issue

  8. Create a different branch for every new task

  9. For every small change, create a commit

  10. push the code to your forked repo

  11. From there send a Pull Request to the parent repo

A word about Commit messages

Keep them meaningful, short and to the point.

Create a Repo of your own and run all listed operations on it.

References/Resources

  • https://help.github.com/articles/set-up-git
  • https://help.github.com/
  • https://try.github.io/levels/1/challenges/1
  • http://www.codecademy.com/blog/74-getting-started-with-git
  • https://help.github.com/articles/setting-guidelines-for-repository-contributors
  • http://stackoverflow.com/questions/10240125/working-with-readme-md-on-github-com
  • http://nvie.com/posts/a-successful-git-branching-model/
  • https://training.github.com/kit/downloads/github-git-cheat-sheet.pdf

Create.Share.Collaborate

Thank you :)

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By Pulkit Goyal

Source: Rishabh Shukla

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