How to understand what a commit is in GitHub?

 
Step 1: Install and configure Git
 

• Download and install Git from the official website (https://git-scm.com).
• Verify the installation by running the following command in your terminal or command prompt:

git --version

• Set your identity so commits are attributed correctly:

git config --global user.name "Your Name"
git config --global user.email "[email protected]"

 
Step 2: Initialize a new Git repository
 

• Create a new folder for your project and navigate into it:

mkdir my-github-project
cd my-github-project

• Initialize an empty Git repository inside that folder:

git init

• This creates a .git directory, where Git stores all versioning data.

 
Step 3: Make changes and stage them for commit
 

• Create or modify a file. For example, create README.md with some content:

echo "# My GitHub Project" > README.md

• See which files are untracked or have changes:

git status

• Stage your changes so they’ll be included in the next commit:

git add README.md

 
Step 4: Create your first commit
 

• Run the commit command with a descriptive message:

git commit -m "Add initial README with project title"

• Git records a _commit_ object containing:
• A unique SHA-1 hash identifying the commit.
• Your author name and email.
• The commit timestamp.
• The snapshot of all staged files.
• The commit message you provided.

 
Step 5: View your commit history locally
 

• List all commits in the current branch:

git log

• You’ll see output similar to:

commit 9fceb02d0ae598e95dc970b74767f19372d61af8
Author: Your Name <[email protected]>
Date:   Mon Apr 5 10:15:30 2021 -0400

Add initial README with project title

• Press q to exit the log view.

 
Step 6: Push commits to GitHub
 

• Create a new repository on GitHub (via the website) with no initial files.
• Link your local repo to GitHub by adding a remote named origin:

git remote add origin https://github.com/your-username/your-repo.git

• Push your commits to the main branch:

git push -u origin main

 
Step 7: Explore commits on GitHub’s web interface
 

• Open your repository on GitHub.
• Click the “Commits” link to see a list of all commits.
• Each entry shows the SHA, author, date, and commit message.
• Click a commit hash to view detailed changes (diff) for each file.

 
Step 8: Understand the anatomy of a commit
 

• SHA-1 hash: Unique identifier for the commit.
• Author Information: Who made the change.
• Date and Timestamp: When the commit was created.
• Commit Message: Human-readable description of the change.
• Parent Commits: Link to previous commits (merges have multiple parents).
• Tree Object: Snapshot of the project’s files at that moment.

 
Step 9: Best practices for writing commit messages
 

• Keep the title line under 50 characters.
• Start with a capital letter and use the imperative mood (e.g., “Fix bug” not “Fixed bug”).
• Separate subject from body with a blank line.
• Explain _what_ and _why_, not _how_.

 
Step 10: Further exploration
 

• Use git show <SHA> to inspect a single commit in detail.
• Experiment with branching and merging to see how commits combine.
• Review GitHub’s “Insights” tab for network graphs and contribution history.