Introduction To Git - agastya2002/IECSE-ML-Winter-2020 GitHub Wiki

Introduction to Github

Git is a free and open-source version control system, that helps you keep track of changes to files in a filesystem/repository over time. It has been an industry standard for a while now. Git comes with the git-shell which has a set of nifty commands that can help you do all sorts of things on your repositories.

Github is a service that hosts your repositories online and lets you collaborate with others through it. You can use Github through the browser or the git-shell on your pc. Github also helps you collaborate with people around the globe!

Collaborators from different regions around the world can work on the same projects, with the help of Github, as it helps to access code by other programmers, really easy!

How to Install Git and Github

Installing Git on Windows

Download Git from Git for Windows and install it
Installing Git on Linux

Determine which Linux distribution your system is based on. See List of Linux distributions – Wikipedia for a list. Most Linux systems – including Ubuntu – are Debian-based.

Debian-based linux systems

Open a terminal window. Copy & paste the following into the terminal window and hit Return. You may be prompted to enter your password.

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install git

You can use Git now.

Installing Git on a Mac

Open a terminal window.

Step 1 – Install Homebrew

Homebrew simplifies the installation of software on the Mac OS X operating system.

Copy & paste the following into the terminal window and hit Return.

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew doctor

You will be offered to install the Command Line Developer Tools from Apple. Confirm by clicking Install. After the installation finished, continue installing Homebrew by hitting Return again.

Step 2 – Install Git

Copy & paste the following into the terminal window and hit Return.

brew install git

You can use Git now.

Git Cheat Sheet

You don't have to remember or understand all of these right now. This is only a cheat sheet so treat it as a cheat sheet. Refer to it as and when you need to.

Create Repositories

To clone an existing repository:

$gitdonessh://[email protected]/repo.git

To create a new local repository:

$ git init

Configure Tooling

Configure user information for all local repositories

Sets the name you want attached to your commit transactions:

$ git config --global user.name "[name]"

Sets the email you want attached to your commit transactions:

$ git config --global user.email "[email address]"

Enables helpful colorisation of the command line output:

$ git config --global color.ui.auto

Make Changes

Review edits and craft a commit transaction

Lists all the modified files to be committed:

$ git status

Shows file differences not yet staged:

$ git diff

Snapshots the file preparation for versioning:

$ git add[file]

Shows file differences between staging and the last final version:

$ git staged --staged

Unstages the file, but preserves its contents:

$ git reset [file]

Records file snapshots permanently in version history:

$ git commit - m "[descriptive message]"

Group Changes

Name a series of commits and combine completed effort

Lists all the local branches in the current repository:

$ git branch

Creates new branch:

$ git branch [branch name]

Switches to specified branch and updates the working directory:

$ git checkout [branchname]

Create new branch and switch simultaneously (Preferred):

$ git checkout -b [branchname]

Combines specified branch's history into the current branch:

$ git merge [branch name]

Deletes the specified branch:

$ git branch -d [branch name]

Refactor Filenames

Relocate and remove versioned files

Deletes the file from the working directory and stages the deletion:

$ git rm [file]

Removes the file from the version control but preserves the file locally:

$ git rm -- cached [file]

Changes the file name and prepares for commit:

$ git mv [file-original] [file-renamed]

Supress Tracking

Exclude temporary files and paths

A text file named .gitignore supressess accidental versioning of files and paths matching the specified patterns:

*. log build/temp- *

Lists all ignored files in this project:

$ git ls-files --other --ignored --exclude-standard

Save Fragments

Shelve and restore incomplete changes

Temporarily stores all the modified tracked files:

$ git stash

Restores the most recently stashed files:

$ git stash pop

Lists all stashed:

$ git stash list

Discards the most recently stashed changeset:

$ git stash drop

Review History

Browse and inspect the evolution of project files

Lists version history for current branch:

$ git log

Lists version history for a file, including renames:

$ git log --follow[file]

Shows content differences between two branches:

$ git diff [first-branch] . . . [second branch]

Outputs metadata and content changes of the specified commit:

$ git show [commit]

Redo Commits

Erase mistakes and craft replacement history

Undoes all commits after [commit], preserving changes locally:

$ git reset

Discards all hsitory and changes back to the specified commit:

$ git reset --hard [commit]

Synchronize Changes

Register a repository bookmark and exchange version history

Downloads all history from the repository bookmark:

$ git fetch [bookmark]

Combines bookmark's branch into the curent local branch:

$ git merge [bookmark]/[branch]

Uploads all local branch commits to GitHub:

$ git push [alias] [branch]

Downloads bookmark history and incorporates changes:

$ git pull