Lesson 6: Push and Pull

What You'll Learn

In this lesson, you'll learn how to synchronize your local repository with GitHub using git push and git pull. These are the commands you'll use daily to share your work and get updates from others.

Understanding Push and Pull

Think of it like:

• Push = Uploading photos to Google Photos
• Pull = Downloading photos from Google Photos

Part 1: Pushing Changes to GitHub

The Basic Push Command

git push

This uploads your committed changes to GitHub.

First Time Push

The first time you push a branch, use:

git push -u origin main

After the first time, you can just use git push.

Part 2: Complete Push Workflow

Here's the typical workflow for making changes and pushing them:

# 1. Make changes to your files
# (edit index.html, add new files, etc.)

# 2. Check what changed
git status

# 3. Stage the changes
git add .

# 4. Commit with a message
git commit -m "Add contact form"

# 5. Push to GitHub
git push

Example Scenario

Let's say you added a new feature:

$ git add .
$ git commit -m "Add navigation menu"
[main abc1234] Add navigation menu
 1 file changed, 15 insertions(+)

$ git push
Counting objects: 3, done.
Writing objects: 100% (3/3), 287 bytes | 287.00 KiB/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To github.com:username/my-project.git
   def5678..abc1234  main -> main

Your changes are now on GitHub! 🎉

Part 3: Pulling Changes from GitHub

The Pull Command

git pull

This downloads commits from GitHub and merges them into your local branch.

When to Pull

• Before starting work - get the latest code
• When collaborating - get changes from teammates
• When you edit on different computers - sync your work
• Before pushing - ensure you have the latest changes

Part 4: Understanding git fetch

Git pull is actually two commands combined:

git pull = git fetch + git merge

When to Use Fetch

# Check for remote changes without merging
git fetch

# See what would change
git log HEAD..origin/main

# If you like the changes, merge them
git merge origin/main

Part 5: Common Push/Pull Scenarios

Scenario 1: Push Rejected

If someone else pushed changes first, you'll see:

$ git push
! [rejected]        main -> main (fetch first)
error: failed to push some refs to 'github.com:username/project.git'

Solution: Pull first, then push

git pull
git push

Scenario 2: Working on Multiple Computers

On Computer A:

git add .
git commit -m "Update homepage"
git push

On Computer B:

git pull  # Get the changes from Computer A
# Continue working...

Scenario 3: Edited Same File on GitHub and Locally

If you edit a file on GitHub's website and also locally:

# Pull first to get GitHub changes
git pull

# If there's a conflict, resolve it (we'll cover this later)
# Then commit and push
git add .
git commit -m "Merge remote changes"
git push

Part 6: Viewing Remote Information

Check Your Remote

git remote -v

Output shows:

origin  git@github.com:username/project.git (fetch)
origin  git@github.com:username/project.git (push)

Add a Remote

git remote add origin https://github.com/username/project.git

Change Remote URL

git remote set-url origin git@github.com:username/project.git

Practice Exercise

1. In your git-practice repository from last lesson:
   • Edit the README.md file
   • Add a new file called notes.txt
2. Stage and commit your changes:

   git add .
   git commit -m "Update README and add notes"

3. Push to GitHub:

   git push

4. Go to GitHub and verify your changes appear
5. Edit README.md directly on GitHub
6. Pull the changes back to your local machine:

   git pull

Summary

Best Practice: Always pull before you push to avoid conflicts!

What's Next?

In the next lesson, you'll learn about branches - how to create parallel versions of your code to work on features without affecting the main codebase.