majiayu000 Git Introduction Skill
Production-Grade Learning Skill | Version 2.0.0
Your first steps into the world of version control.
Skill Contract
Input Schema
input:
type: object
properties:
topic:
type: string
enum: [what-is-git, why-use-git, installation, first-setup, first-repo]
default: what-is-git
os:
type: string
enum: [macos, windows, linux, unknown]
default: unknown
experience_level:
type: string
enum: [complete-beginner, some-coding, used-other-vcs]
default: complete-beginner
validation:
custom: true
rules:
- if_unknown_os: detect_from_environment
Output Schema
output:
type: object
required: [explanation, success]
properties:
explanation:
type: string
format: markdown
success:
type: boolean
visual_aid:
type: string
description: ASCII diagram if applicable
next_steps:
type: array
items:
type: string
commands_to_try:
type: array
items:
type: object
properties:
command: string
description: string
safe: boolean
Error Handling
Validation Rules
parameter_validation:
topic:
required: false
sanitize: lowercase_trim
fallback: what-is-git
os:
required: false
auto_detect: true
detection_command: uname -s || ver
Retry Logic
retry_config:
max_attempts: 2
backoff_ms: [1000, 2000]
retryable_scenarios:
- command_timeout
- os_detection_failed
Fallback Strategy
fallback:
- scenario: installation_failed
action: provide_manual_instructions
- scenario: command_not_found
action: check_path_and_suggest
What is Git?
Without Git With Git
────────── ─────────
report_v1.doc report.doc
report_v2.doc │
report_final.doc ├─ commit 1: "Initial draft"
report_final_v2.doc ├─ commit 2: "Added intro"
report_REALLY_final.doc ├─ commit 3: "Fixed typos"
report_final_final.doc └─ commit 4: "Final version"
Chaos! Clean history!
Why Use Git?
| Problem | Git Solution |
|---|---|
| "Which version is latest?" | Single file, full history |
| "I broke everything!" | Time travel to any point |
| "Who changed this?" | Blame/log shows author |
| "Can't work together" | Branches, merge, resolve |
| "Lost my work!" | Every commit is backup |
Key Concepts
The Three Areas
┌─────────────────────────────────────────────────────────────┐
│ │
│ Working Directory Staging Area Repository │
│ (Your Workspace) (Ready Room) (Safe Storage) │
│ │
│ 📁 ──────────► 📦 ──────────────► 🏠 │
│ git add git commit │
│ │
└─────────────────────────────────────────────────────────────┘
Commits = Save Points
commit 3 ← (HEAD - You are here)
↓
commit 2 ← You can go back
↓
commit 1 ← Or even further back!
Installation
macOS
# Option 1: Xcode Command Line Tools (recommended)
xcode-select --install
# Option 2: Homebrew
brew install git
Windows
# Option 1: Git for Windows (recommended)
# Download from https://git-scm.com/download/windows
# Option 2: winget
winget install --id Git.Git -e --source winget
Linux
# Ubuntu/Debian
sudo apt install git
# Fedora
sudo dnf install git
# Arch
sudo pacman -S git
Verify Installation
git --version
# Expected: git version 2.42.0 (or similar)
First-Time Setup
# Tell Git who you are (REQUIRED)
git config --global user.name "Your Name"
git config --global user.email "your.email@example.com"
# Optional but recommended
git config --global init.defaultBranch main
git config --global core.editor "code --wait" # VS Code
# Verify your settings
git config --list
Your First Repository
# 1. Create a folder
mkdir my-first-project
cd my-first-project
# 2. Initialize Git (creates .git folder)
git init
# Output: Initialized empty Git repository in .../my-first-project/.git/
# 3. Create a file
echo "# My Project" > README.md
# 4. Check status
git status
# Output: Untracked files: README.md
# 5. Stage the file
git add README.md
# 6. Commit (save!)
git commit -m "Initial commit: Add README"
# 7. View history
git log --oneline
Quick Reference Card
┌────────────────────────────────────────────────────────────┐
│ GIT CHEAT SHEET │
├────────────────────────────────────────────────────────────┤
│ START │
│ git init Create new repo │
│ git clone <url> Download existing repo │
│ │
│ DAILY WORK │
│ git status What's going on? │
│ git add <file> Stage file │
│ git add . Stage all │
│ git commit -m "msg" Save with message │
│ │
│ HISTORY │
│ git log View commits │
│ git log --oneline Compact view │
│ git diff See changes │
└────────────────────────────────────────────────────────────┘
Troubleshooting Guide
Debug Checklist
□ 1. Is Git installed? → git --version
□ 2. Correct version? → Should be 2.x or higher
□ 3. User configured? → git config user.name
□ 4. Editor set? → git config core.editor
Common Issues
| Issue | Cause | Solution |
|---|---|---|
| "command not found: git" | Not installed or not in PATH | Reinstall or add to PATH |
| "Author identity unknown" | User not configured | Run git config commands |
| "not a git repository" | Missing .git folder | Run git init |
Log Patterns
# Successful init
Initialized empty Git repository in /path/.git/
# Successful commit
[main abc1234] Your message
1 file changed, 1 insertion(+)
Unit Test Template
#!/bin/bash
# test_git_intro.sh
test_git_installed() {
git --version > /dev/null 2>&1
assertEquals 0 $?
}
test_user_configured() {
name=$(git config user.name)
assertNotNull "$name"
}
test_init_creates_git_folder() {
tmpdir=$(mktemp -d)
cd "$tmpdir"
git init
assertTrue "[ -d .git ]"
rm -rf "$tmpdir"
}
Observability
logging:
level: INFO
events:
- skill_invoked
- installation_checked
- config_verified
- first_commit_created
metrics:
- installation_success_rate
- time_to_first_commit
- common_error_types
Next Steps
After mastering this skill, proceed to:
- basic-workflow - Daily Git operations
- git-basics - Deeper understanding
- branching - Work in parallel
"Every expert was once a beginner. Welcome to Git!"