Advanced Git Workshop

Welcome to the Advanced Git and GitHub/GitLab Workshop at EPAM Systems!

1. Git Basics

What is a Git Repository?

• A Git repository is a version-controlled project folder.
• Every project (e.g., portfolio, app, website) should have its own repository.
• You can have multiple repositories on your machine, each with its own history.

Making a Commit

• A commit is like saving your work—it captures a snapshot of your project.
• Commits can include multiple files or folders.

Examples of files in a commit:

• main.html, chatbot.js, mobile.css, logos/

Common Git Workflow

2. Working with Changes

Checking Repository Status

• Shows which files are staged, unstaged, or untracked.

git status

Tip: If you're not inside a Git repo, you'll see:

fatal: not a git repository

Starting a New Repository

• Initializes a Git repo in the current directory.

git init

Advice:

• Don't create a Git repo inside another one.
• Use git status to check.
• Mistake? Delete the .git folder.

Tracking Changes

• Git watches your files after you run git init.
• New files show up as untracked.

Staging Changes

• Moves selected changes to the staging area.

git add file1 file2  # Add specific files
git add .            # Add everything

Committing Changes

• Saves all staged changes to the repository.
• A commit message is required.

git commit
git commit -m "Initial commit"

Reminder: Use git status often to see what's staged.

3. Managing Commits

Writing Inline Messages

git commit -m "Fix login bug"

Amending a Commit

• Fix the most recent commit (add files or change message).

git add missed_file
git commit --amend

Good Commit Practices

• Make frequent commits to keep history clear.
• Each commit should represent one logical change.
• Write clear, short messages.

Commit Message Style

• Use command-like style (e.g., Fix typo, not Fixed typo).
• Be consistent with your style.

4. Ignoring Files

When to Use .gitignore

• For files you don't want in version control, like:
  • Secrets, credentials, API keys
  • System files like .DS_Store
  • Logs, dependency folders like node_modules

Example:

.DS_Store
*.log
folderName/

5. Comparing Changes

What You Can Compare with git diff

• Working directory vs staging area
• Staging area vs last commit
• Specific commits or branches

Common Diff Commands

git diff             # Unstaged changes
git diff HEAD        # Changes since last commit
git diff --staged    # Staged vs last commit
git diff commit1..commit2
git diff branchA..branchB

How to Read a Diff

- removed line
+ added line
@@ context indicator

• Changes are grouped into chunks.
• Headers show which lines changed.

Diffing a Specific File

git diff HEAD file.js
git diff --staged file.js

6. Saving Work Without Committing

Using Git Stash

• Temporarily save changes so you can switch tasks.

git stash           # Save changes
git stash pop       # Reapply and delete
git stash apply     # Reapply without deleting
git stash -u        # Include untracked files

Managing Multiple Stashes

git stash list
git stash apply stash@{2}
git stash drop stash@{2}
git stash clear

7. Undoing and Recovering Changes

Checking Out Commits

• Move between branches or revisit older commits.

git checkout <commit>
git switch master
git switch -c temp-branch

Referring to Previous Commits

git checkout HEAD~2  # Go back two commits

Reverting File Changes

git checkout -- file.js
git restore file.js
git restore --source HEAD~1 file.js
git restore --staged file.js

8. Resetting vs Reverting

git reset

• Undoes commits (used for private/local work).

git reset <commit>
git reset --hard <commit>

git revert

• Reverses changes by creating a new commit (safe for shared repos).

git revert <commit>

When to Use Each