Git Basic Commands¶

1. Check File Status - git status¶

Check the current state of the repository.

git status

Four States of Files¶

┌───────────────────────────────────────────────────────────┐
│                    File State Changes                      │
├───────────────────────────────────────────────────────────┤
│                                                           │
│  Untracked ──(git add)──▶ Staged ──(git commit)──▶ Committed
│      │                       │                            │
│      │                       │                            │
│      ▼                       ▼                            │
│  (New file)            (Tracked file)              (Saved)│
│                                                           │
└───────────────────────────────────────────────────────────┘

Untracked: New files that Git is not tracking
Modified: Files that have been modified but not staged
Staged: Files waiting to be committed
Committed: Files saved in the repository

2. Staging - git add¶

Add files to the staging area.

# Add specific file
git add filename

# Add multiple files
git add file1 file2 file3

# Add all changed files in current directory
git add .

# Add all files with specific extension
git add *.js

Practice Example¶

# Create files
echo "Hello Git" > hello.txt
echo "Bye Git" > bye.txt

# Check status - Untracked state
git status

# Stage only hello.txt
git add hello.txt

# Check status - hello.txt is staged, bye.txt is untracked
git status

3. Commit - git commit¶

Record staged changes to the repository.

# Commit with message
git commit -m "Commit message"

# Write longer message in editor
git commit

# Add and commit simultaneously (tracked files only)
git commit -am "Message"

Good Commit Message Practices¶

# Good examples
git commit -m "Add login functionality"
git commit -m "Fix: email validation error in signup"
git commit -m "Update README: add installation instructions"

# Bad examples
git commit -m "Update"
git commit -m "asdf"
git commit -m "WIP"

Commit Message Convention (Conventional Commits)¶

Type: Subject

feat: Add new feature
fix: Fix bug
docs: Update documentation
style: Code formatting (no functionality change)
refactor: Code refactoring
test: Add tests
chore: Build, configuration file updates

4. View Commit History - git log¶

View the commit history of the repository.

# Basic log
git log

# One line per commit
git log --oneline

# View as graph
git log --oneline --graph

# Show only last 5 commits
git log -5

# Show history of specific file
git log filename

# Show with change details
git log -p

Output Example¶

$ git log --oneline
a1b2c3d (HEAD -> main) Third commit
e4f5g6h Second commit
i7j8k9l First commit

5. View Changes - git diff¶

Compare changes in files.

# Working directory vs staging area
git diff

# Staging area vs latest commit
git diff --staged

# Compare specific commits
git diff commit1 commit2

# Specific file only
git diff filename

Output Example¶

diff --git a/hello.txt b/hello.txt
index 8d0e412..b6fc4c6 100644
--- a/hello.txt
+++ b/hello.txt
@@ -1 +1,2 @@
 Hello Git
+Nice to meet you!

- Red: Deleted line
+ Green: Added line

6. Undo Changes¶

Unstage (git restore --staged)¶

# Unstage specific file
git restore --staged filename

# Unstage all files
git restore --staged .

Discard Modifications (git restore)¶

# Discard modifications to specific file (Warning: changes will be lost!)
git restore filename

# Discard all modifications
git restore .

Amend Last Commit (git commit --amend)¶

# Modify message only
git commit --amend -m "New commit message"

# Add forgotten file to commit
git add forgotten-file.txt
git commit --amend --no-edit

Practice Example: Complete Workflow¶

# 1. Start new project
mkdir git-workflow
cd git-workflow
git init

# 2. Create and commit first file
echo "# My Project" > README.md
git status                    # Check Untracked
git add README.md
git status                    # Check Staged
git commit -m "feat: Initialize project"

# 3. Modify file and commit
echo "This is my project" >> README.md
git diff                      # Check changes
git add .
git commit -m "docs: Add README description"

# 4. Add new file
echo "console.log('Hello');" > app.js
git add app.js
git commit -m "feat: Add main app file"

# 5. View history
git log --oneline

Expected result:

c3d4e5f (HEAD -> main) feat: Add main app file
b2c3d4e docs: Add README description
a1b2c3d feat: Initialize project

Command Summary¶

Command	Description
`git status`	Check current status
`git add <file>`	Add to staging area
`git add .`	Add all changed files
`git commit -m "message"`	Create commit
`git log`	View commit history
`git log --oneline`	View brief history
`git diff`	Compare changes
`git restore --staged <file>`	Unstage
`git restore <file>`	Discard modifications

Next Steps¶

Let's learn about parallel work using branches in 03_Branches.md!