Git Commands Every Junior Developer Should Master

# ❌ Don't do this
git commit -m "fixed stuff"
git commit -m "updates"
git commit -m "asdf"

# ✅ Good commit messages
git commit -m "fix: resolve null pointer in user login

- Add null check before accessing user.email property
- Add test case for login with missing email
- Fixes #247"

# Follow conventional commits
git commit -m "feat: add dark mode toggle to navigation"
git commit -m "refactor: simplify authentication logic"
git commit -m "docs: update API documentation for v2 endpoints"
git commit -m "test: add unit tests for payment validation"

<type>: <short summary>

<optional body>
- Bullet point changes
- Be specific about what changed

<optional footer>
Fixes #issue-number

# See what's changed
git status

# See what's different (before staging)
git diff

# See what's staged for commit
git diff --staged

# Compare branches
git diff main..feature-branch

# See changes in a specific file
git diff path/to/file.ts

# Old way (still works)
git branch feature-login
git checkout feature-login

# Better way
git checkout -b feature-login

# Modern way (Git 2.23+)
git switch -c feature-login

# Switch to existing branch
git switch main

# List all branches
git branch -a

# List remote branches only
git branch -r

# Delete a local branch
git branch -d feature-login

# Force delete (if not merged)
git branch -D feature-login

# Delete remote branch
git push origin --delete feature-login

# Rename current branch
git branch -m new-branch-name

# Feature development
git switch -c feature/user-authentication

# Bug fixes
git switch -c fix/login-validation-error

# Hotfix for production
git switch -c hotfix/security-patch

# Fetch: Download changes but don't merge
git fetch origin

# See what's new
git log HEAD..origin/main

# Pull: Fetch + Merge
git pull origin main

# Pull with rebase (cleaner history)
git pull --rebase origin main

# Push current branch
git push

# Set upstream and push
git push -u origin feature-login

# Force push (use with caution!)
git push --force-with-lease

# ⚠️ Never use on shared branches!
git push --force

# Unstage a specific file
git restore --staged file.ts

# Unstage all files
git restore --staged .

# Old way (still works)
git reset HEAD file.ts

# Discard changes in a specific file
git restore file.ts

# Discard all changes (be careful!)
git restore .

# Old way
git checkout -- file.ts

# Undo last commit, keep changes staged
git reset --soft HEAD~1

# Undo last commit, keep changes unstaged
git reset HEAD~1

# Undo last commit, discard all changes ⚠️
git reset --hard HEAD~1

# Undo multiple commits
git reset --soft HEAD~3

# Oops, committed to main instead of a feature branch!

# 1. Create the feature branch (keeps the commits)
git branch feature-my-work

# 2. Reset main to match remote
git reset --hard origin/main

# 3. Switch to feature branch
git switch feature-my-work

# 4. Now your commits are safe on the feature branch!

# Create a new commit that undoes changes
git revert abc123

# Revert multiple commits
git revert abc123 def456

# Revert without committing yet
git revert --no-commit abc123

# Save current work
git stash

# Or with a message
git stash save "WIP: user authentication form"

# List stashes
git stash list

# Apply most recent stash
git stash pop

# Apply specific stash
git stash apply stash@{1}

# Apply and keep in stash
git stash apply

# Delete stash
git stash drop stash@{0}

# Clear all stashes
git stash clear

# Working on feature-login
git stash save "half-done: login form validation"

# Switch to main and fix bug
git switch main
git pull
# ... make fixes ...
git commit -m "fix: critical security patch"
git push

# Back to feature
git switch feature-login
git stash pop
# Continue working

# Rebase last 3 commits
git rebase -i HEAD~3

# This opens an editor with:
# pick abc123 feat: add login form
# pick def456 fix: typo
# pick ghi789 feat: add validation

# pick = use commit
# reword = change commit message
# edit = pause to amend commit
# squash = combine with previous commit
# fixup = like squash, but discard commit message
# drop = remove commit

pick abc123 feat: add login form
fixup def456 fix: typo in login form
fixup ghi789 fix: another small fix
reword jkl012 feat: add validation

# Results in 2 clean commits instead of 4 messy ones

# Apply a specific commit from another branch
git cherry-pick abc123

# Cherry-pick multiple commits
git cherry-pick abc123 def456

# Cherry-pick without committing
git cherry-pick --no-commit abc123

# You made a hotfix on main that's also needed on develop
git switch develop
git cherry-pick <hotfix-commit-hash>

# Basic log
git log

# One line per commit
git log --oneline

# Last 5 commits
git log -5

# Show commits with diffs
git log -p

# Graph view (amazing for branches)
git log --graph --oneline --all

# Commits by specific author
git log --author="Your Name"

# Commits in date range
git log --since="2 weeks ago"

# Search commit messages
git log --grep="login"

# See what changed in a file
git log -p path/to/file.ts

# Add to ~/.gitconfig
[alias]
    lg = log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit

# Then use: git lg

# See who modified each line
git blame file.ts

# Blame for specific lines
git blame -L 10,20 file.ts

# Ignore whitespace changes
git blame -w file.ts

# Show commit details
git show abc123

# Show changes in a commit
git show abc123 --stat

# Show specific file from a commit
git show abc123:path/to/file.ts

[alias]
    # Short status
    s = status -s
    
    # Add all and commit
    ac = !git add -A && git commit
    
    # Commit with message
    cm = commit -m
    
    # Amend last commit
    amend = commit --amend --no-edit
    
    # Pretty log
    lg = log --graph --oneline --decorate --all
    
    # Undo last commit
    undo = reset HEAD~1 --mixed
    
    # List branches sorted by last modified
    br = branch --sort=-committerdate
    
    # Show current branch
    current = branch --show-current

# Remove file from last commit
git rm --cached .env
git commit --amend --no-edit

# If already pushed (⚠️ rewrites history)
git push --force-with-lease

# Binary search through commits
git bisect start
git bisect bad                 # Current commit is bad
git bisect good abc123         # This commit was good
# Git checks out middle commit, test it
git bisect bad                 # or git bisect good
# Repeat until found
git bisect reset

# View all reference changes
git reflog

# Find your lost commit
git reflog show HEAD

# Restore it
git cherry-pick abc123

# Daily workflow
git status                     # Check status
git add .                      # Stage all changes
git commit -m "message"        # Commit
git push                       # Push to remote

# Branching
git switch -c feature-name     # Create new branch
git switch main                # Switch branch
git branch -d feature-name     # Delete branch

# Syncing
git pull                       # Update current branch
git fetch                      # Download updates

# Fixing mistakes
git restore file.ts            # Discard changes
git reset HEAD~1               # Undo last commit
git stash                      # Save work for later

# History
git log --oneline              # View commits
git diff                       # See changes