Git Essentials

Essential Git commands for version control and collaboration.

Initial Setup

# Configure user
git config --global user.name "Your Name"
git config --global user.email "your@email.com"

# Initialize repository
git init

# Clone repository
git clone https://github.com/user/repo.git
git clone https://github.com/user/repo.git custom-name

Basic Workflow

Staging and committing

# Check status
git status

# Add files to staging
git add file.txt
git add .
git add -A  # All changes including deletions

# Commit changes
git commit -m "Commit message"

# Add and commit in one step
git commit -am "Message"

# Amend last commit
git commit --amend -m "New message"
git commit --amend --no-edit  # Keep message

Viewing changes

# Show unstaged changes
git diff

# Show staged changes
git diff --staged

# Show changes in specific file
git diff file.txt

# Show changes between commits
git diff commit1 commit2

Branching & Merging

Branch management

# List branches
git branch
git branch -a  # Include remote branches

# Create branch
git branch feature-name

# Switch branch
git checkout feature-name
git switch feature-name  # Modern alternative

# Create and switch
git checkout -b feature-name
git switch -c feature-name

# Delete branch
git branch -d branch-name
git branch -D branch-name  # Force delete

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

Merging

# Merge branch into current
git merge feature-name

# Merge with no fast-forward
git merge --no-ff feature-name

# Abort merge
git merge --abort

# Show merge conflicts
git diff --name-only --diff-filter=U

Remote Operations

Managing remotes

# List remotes
git remote -v

# Add remote
git remote add origin https://github.com/user/repo.git

# Change remote URL
git remote set-url origin https://github.com/user/new-repo.git

# Remove remote
git remote remove origin

Syncing with remote

# Fetch from remote
git fetch origin

# Pull changes (fetch + merge)
git pull

# Pull with rebase
git pull --rebase

# Push changes
git push

# Push new branch
git push -u origin branch-name

# Force push (careful!)
git push --force-with-lease

History & Logs

Viewing history

# Show commit history
git log

# One line per commit
git log --oneline

# With graph
git log --graph --oneline --all

# Last N commits
git log -5

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

# Commits in date range
git log --since="2 weeks ago"
git log --until="2024-01-01"

# File history
git log -- file.txt

Searching history

# Search commit messages
git log --grep="bug fix"

# Search code changes
git log -S "function_name"

# Show who changed each line
git blame file.txt

# Find commit that introduced bug
git bisect start
git bisect bad
git bisect good commit-hash

Undoing Changes

Working directory

# Discard changes in file
git restore file.txt
git checkout -- file.txt  # Old way

# Discard all changes
git restore .

Staging area

# Unstage file
git restore --staged file.txt
git reset HEAD file.txt  # Old way

# Unstage all
git reset

Commits

# Undo last commit (keep changes)
git reset --soft HEAD~1

# Undo last commit (discard changes)
git reset --hard HEAD~1

# Revert commit (create new commit)
git revert commit-hash

# Reset to specific commit
git reset --hard commit-hash

Stashing

# Stash changes
git stash

# Stash with message
git stash save "Work in progress"

# List stashes
git stash list

# Apply latest stash
git stash apply

# Apply and remove stash
git stash pop

# Apply specific stash
git stash apply stash@{2}

# Delete stash
git stash drop stash@{0}

# Clear all stashes
git stash clear

Rebasing

# Rebase current branch
git rebase main

# Interactive rebase (last 3 commits)
git rebase -i HEAD~3

# Continue after resolving conflicts
git rebase --continue

# Skip current commit
git rebase --skip

# Abort rebase
git rebase --abort

Advanced Operations

Cherry-pick

# Apply specific commit
git cherry-pick commit-hash

# Cherry-pick without committing
git cherry-pick -n commit-hash

Submodules

# Add submodule
git submodule add https://github.com/user/repo.git path/

# Initialize submodules
git submodule init

# Update submodules
git submodule update

# Clone with submodules
git clone --recursive https://github.com/user/repo.git

Clean

# Preview files to be deleted
git clean -n

# Delete untracked files
git clean -f

# Delete untracked files and directories
git clean -fd

# Include ignored files
git clean -fdx

Common Workflows

Feature branch workflow:

git checkout -b feature/new-feature
# Make changes
git add .
git commit -m "Add new feature"
git push -u origin feature/new-feature
# Create PR, then after merge:
git checkout main
git pull
git branch -d feature/new-feature

Hotfix workflow:

git checkout main
git pull
git checkout -b hotfix/critical-bug
# Fix bug
git commit -am "Fix critical bug"
git push -u origin hotfix/critical-bug
# After merge:
git checkout main && git pull

Syncing fork:

git remote add upstream https://github.com/original/repo.git
git fetch upstream
git checkout main
git merge upstream/main
git push origin main

Useful Aliases

Add to ~/.gitconfig:

[alias]
    st = status
    co = checkout
    br = branch
    ci = commit
    unstage = reset HEAD --
    last = log -1 HEAD
    visual = log --graph --oneline --all
    amend = commit --amend --no-edit

Tips

Commit often, perfect later (interactive rebase)
Write meaningful commit messages
Use .gitignore for files to exclude
Never force push to shared branches
Pull before starting work
Use feature branches, not main
Rebase feature branches before merging
Use --force-with-lease instead of --force

Common Issues

Undo accidental commit:

git reset --soft HEAD~1

Recover deleted branch:

git reflog
git checkout -b branch-name <commit-hash>

Fix wrong commit message:

git commit --amend -m "Correct message"

Resolve merge conflicts:

# Edit files to resolve conflicts
git add resolved-files
git commit  # Or git merge --continue

Documentation

Official docs: https://git-scm.com/doc

Pro Git book: https://git-scm.com/book

Visual Git guide: https://marklodato.github.io/visual-git-guide/

Git Essentialsv1.0.0

Install & Quick Start