Git

What is Git?

Git is a version control system that allows you to keep track of changes made to a project over time.

What is GitHub?

GitHub is a popular hosting service for Git repositories. GitHub allows you to store your local Git repositories in the cloud. With GitHub, you can backup your files, share your code, and collaborate with others.

Step 1: Install Git for Mac

To install Git on Mac, we first need to install Homebrew.

Step 1.1: Install Homebrew

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

Step 1.2: Install Git

brew install git

Step 2: Configure Git and Github

Step 2.1: Set up Git

For Git to work properly, we need to configure Git with the following commands. Enter your information inside the quotes. It’s a good idea to use the same email as your Github account email.

git config --global user.name "Your Name"
git config --global user.email "yourname@example.com"

To verify that the output matches your name and email address.

git config --get user.name
git config --get user.email

Go to GitHub.com and create an account. If you already have one, sign in.

Step 2.3: Create SSH Key

Check if you have an SSH key

ls ~/.ssh/id_rsa.pub

If you receive a message “No such file or directory”, you’ll need to create a new one. Create SSH To create an SSH key, run the following command

ssh-keygen -C <youremail>

When it asks a location to save the generated key, press Enter.
Next, it will ask you for a password; enter one if you wish, but it’s not required.

Step 2.4: Link Your SSH Key with GitHub

Log into GitHub and click Settings
Click SSH and GPG keys and click New SSH Key
Run this following command in your terminal, copy the output into the key field and click click Add SSH key

cat ~/.ssh/id_rsa.pub

Follow this Github article to test your key

Git Project

A Git project has three parts:

A Working Directory: where you’ll be doing all the work: creating, editing, deleting, and organizing files
A Staging Area: where you’ll list changes you make to the working directory
A Repository: where Git permanently stores those changes as different versions of the project

Git commands

git init initialize a new Git repository
git status check the status of changes
git add filename adds files from the working directory to the staging area
git add filename_1 filename_2 add multiple files to the staging area with a single command:
git diff filename shows the difference between the working directory and the staging area
git commit permanently stores changes from the staging area inside the repository. The option -m followed by a message.

git commit -m "First commit"

Standard commit messages:

Must be in quotation marks
Written in the present tense
Should be brief (50 characters or less) when using -m

git log shows a list of all previous commits. The message includes

A 40-character code, called an SHA, uniquely identifies the commit. This appears in orange text.
The committed author
The date and time of the commit
The commit message

Backtrack Git

In Git, a HEAD commit is the commit you’re currently on.

git checkout HEAD filename restores the file in your working directory to look exactly as it did when you last made a commit. We can also use git checkout -- filename
git reset HEAD filename unstages file changes in the staging area.
git reset commit_SHA resets to a previous commit in your commit history. This command works by using the first 7 characters of the SHA of a previous commit.

Git branch

Git allows users to create branches to experiment with versions of a project. To list all a Git project’s branches, use this command git branch.

Create a new branch

git branch new_branch

Switch to the new branch

git checkout branch_name

Commit on a new branch

All the commands you do on main branch, you can also do on this branch.

To add files to the staging area git add filename
To commit git commit -m "Commit message"

Merge

Firstly, we need to switch to the main branch git checkout main Then use this command to merge the new branch to a main branch git merge branch_name.

Delete branch

After the branch has been integrated into the main, you can delete it.

git branch -d branch_name

If the feature branch is never merged into main branch, we use the -D option.

git branch -D branchname

Git workflow on your own

Initiate Git or Clone GitHub to a local machine.

git clone https://github.com/USER_NAME/REPOSITORY_NAME.git

Create a branch to work on a new project feature and push it to the server:

git branch <name of the branch>
git push -u origin <name of the branch>

For example, if your branch is “develop”, you can enter the following command.

git branch develop
git push -u origin develop

Switch to a the branch

git checkout <name of the branch>

Make changes to the working files
Commit changes:

git status
git add --a
git commit -m "Add your comment here"

After committing, push branch to remote:

git checkout main
git merge <name of the branch>
git push -u- origin main

Git Teamwork

A remote (Git repository) can live on the web, on a shared network, or even in a separate folder on your local computer.

git clone

To create a local copy of a remote:

git clone remote_location clone_name

remote_location tells Git where to go to find the remote.
clone_name is the name you give to the directory in which Git will clone the repository

git remote

See a list of a Git project’s remotes with the command: git remote -v

git fetch

To fetch work from the remote into the local copy: git fetch

git merge

To merge origin/main into your local branch: git merge origin/main

git push

To push a local branch to the origin remote: git push origin <branch_name>.

Git workflow teamwork

Fetch and merge changes from the remote
Create a branch to work on a new project feature
Develop the feature on your branch and commit your work
Fetch and merge from the remote again (in case new commits were made while you were working)
Push your branch up to the remote for review

Resources:

Git