Git & Github

Introduction to Git

Pro Git Book: A comprehensive guide to Git.

Basic Setup after Downloading Git

git --version  # Check Git version

# Change default branch to main
git config --global init.defaultBranch main

git config --global user.name "Your Name"  # Set username
git config --get user.name                   # Retrieve username

git config --global user.email "mail@mail.com"  # Set email
git config --get user.email                   # Retrieve email

git config --global color.ui auto             # Enable colored output

git config --global pull.rebase false         # Disable rebase on pull

git pull: This command is used to fetch changes from a remote repository and merge them into your current branch. By default, it performs a merge.

Rebasing: This is an alternative to merging where Git re-applies your local changes on top of the changes fetched from the remote.

Basic Git Commands

git status       # Show tracked, untracked, staged files


git add [file name]       # Add specific file to staging area
git add .                 # Add all files to staging area


git commit -m "message"   # Commit staged files with a message


git log        # Show commit history
q              # Exit log view if it's too long


git push                # Push changes to the remote repository
git push origin main    # Push the main branch to origin in Github

Using Git in VS Code

Opening VS Code from terminal using: code .
To set VS Code as the default editor for commit messages:

git config --global core.editor "code --wait"

Connecting Git to GitHub with SSH

Setting Up SSH Key

ls ~/.ssh/id_ed25519.pub  # Check if SSH key exists

ssh-keygen -t ed25519     # Create a new SSH key
# Press Enter for default location and no passphrase

cat ~/.ssh/id_ed25519.pub  # Copy the SSH key

Adding SSH Key to GitHub

Go to Settings → SSH and GPG keys.
Click New SSH key and paste the SSH key.

Connecting from GitHub to Git

Creating a New Repository:
- In GitHub, click New repository.
- Select Code, then copy the SSH link (not the HTTP link).

Cloning a Repository from Github

mkdir repos       # Create a new directory
cd repos          # Navigate to that directory

git clone [paste the ssh link]  # Clone the repo from GitHub
cd [the new folder]             # Navigate into the cloned folder
git remote -v                   # Show the linked GitHub repository

Pushing Local Repository to GitHub

git init                  # Initialize a new Git repository

git add .                 # Stage all files

git commit -m "message"   # Commit the changes

Create an empty repository on GitHub (without README or license)

git remote add origin [ssh key]  # Link to the GitHub repository

git branch -M main               # Rename current branch to main (if necessary)

git push -u origin main          # Push changes to GitHub

Commit Messages

Follow the seven rules of a great Git commit message:
1. Separate subject from body with a blank line.
2. Limit subject line to 50 characters.
3. Capitalize the subject line.
4. Do not end the subject line with a period.
5. Use the imperative mood in the subject line.
6. Wrap the body at 72 characters.
7. Explain what and why in the body, not how.
Tutorial Video: Conventional Commits

Branches

Use git branch to see all branches.
To create a new branch:

git branch <branch_name>       # Create a new branch
git checkout <branch_name>     # Switch to the branch


git checkout -b <branch_name>  # Create and switch to a new branch


git checkout main     # Switch back to the main branch

Merging Branches

Move to the branch you want to merge into

git merge <branch_name>  

# Merge changes from <branch_name>

Merge Conflicts

Occur when changes to the same line in a file are made in different branches.

Deleting a Branch

git branch -d <branch_name>  
# Delete a merged branch

git branch -D <branch_name>  
# Force delete an unmerged branch

Pushing a New Branch to GitHub

git checkout -b <branch_name>    
# Create and switch to the new branch


git push origin <branch_name>     
# Push the branch to GitHub


git push -u origin <branch_name>  
# Link the local branch with the remote one

Changing to an Old Commit

git log --oneline        # View commit history
# Get the commit ID from the log

git reset --hard [9digitId]       
# Reset to that commit (deletes progress)

git checkout -b old-state [id]    
# Create a new branch at the old commit

git revert [commit_id]             
# Revert a specific commit

Additional Topics to Explore

Git Workflow Models:
- Overview of workflows like Git Flow, GitHub Flow, etc.
Remote Management:
- How to manage multiple remotes and their configurations.
Stashing Changes:
- Using git stash to temporarily save changes.
Rebasing:
- Introduction to rebasing vs. merging and its implications.
Using Tags:
- How to create and manage tags for releases.
Working with Submodules:
- Overview of using submodules for managing dependencies.
Collaborative Work:
- Best practices for collaborating on GitHub (pull requests, code reviews).
Git Hooks:
- Introduction to hooks for automating tasks at different points in the Git workflow.
Git GUI Clients:

Overview of popular GUI clients for Git and their features.

Troubleshooting Common Issues:

Tips for resolving common Git issues (merge conflicts, detached HEAD, etc.).

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