majiayu000 Git Basics Skill
Production-Grade Learning Skill | Version 2.0.0
Essential Git operations for version control mastery.
Skill Contract
Input Schema
input:
type: object
properties:
command_focus:
type: string
enum: [init, add, commit, status, log, diff, config, all]
default: all
detail_level:
type: string
enum: [quick, standard, deep]
default: standard
include_examples:
type: boolean
default: true
validation:
sanitize_strings: true
Output Schema
output:
type: object
required: [content, success]
properties:
content:
type: string
format: markdown
success:
type: boolean
commands_covered:
type: array
items:
type: object
properties:
name: string
syntax: string
examples: array
common_flags: array
diagrams:
type: array
items:
type: string
Error Handling
Retry Logic
retry_config:
max_attempts: 2
backoff_ms: [1000, 2000]
retryable:
- timeout
- network_error
Parameter Validation
validation_rules:
command_focus:
type: enum
fallback: all
detail_level:
type: enum
fallback: standard
Core Commands Reference
Repository Initialization
# Create new repository
git init
# What it creates:
.git/
├── HEAD # Current branch pointer
├── config # Repository config
├── hooks/ # Git hooks
├── objects/ # Git object store
└── refs/ # Branch/tag references
File Tracking
# Check repository status
git status
# Short status format
git status -s
# M modified
# A added
# ?? untracked
# D deleted
# Add files to staging
git add file.txt # Single file
git add . # All files
git add *.js # Pattern
git add -p # Interactive (patch mode)
Committing Changes
# Commit with message
git commit -m "Add feature"
# Commit with detailed message (opens editor)
git commit
# Amend last commit
git commit --amend
# Skip staging (tracked files only)
git commit -am "Quick fix"
Viewing History
# Full log
git log
# One line per commit
git log --oneline
# With graph visualization
git log --oneline --graph --all
# Last N commits
git log -5
# File history
git log --follow -- file.txt
# Search commits
git log --grep="bug"
git log --author="Name"
git log --since="2 weeks ago"
Viewing Changes
# Working directory changes
git diff
# Staged changes
git diff --staged
# Between commits
git diff abc123 def456
# Specific file
git diff HEAD~3 -- file.txt
# Statistics only
git diff --stat
Command Quick Reference
| Command | Purpose | Common Flags | Example |
|---|---|---|---|
git init |
Create repo | - | git init |
git clone |
Copy repo | --depth, --branch |
git clone URL |
git status |
Check state | -s, -b |
git status -s |
git add |
Stage files | -p, -A |
git add . |
git commit |
Save changes | -m, --amend |
git commit -m "msg" |
git log |
View history | --oneline, --graph |
git log --oneline |
git diff |
See changes | --staged, --stat |
git diff --staged |
git show |
Show commit | - | git show abc123 |
Understanding Git Objects
┌─────────────────────────────────────────────────────────┐
│ GIT OBJECTS │
├─────────────────────────────────────────────────────────┤
│ │
│ BLOB ─ File content (compressed) │
│ TREE ─ Directory listing (blob + tree refs) │
│ COMMIT ─ Snapshot + metadata + parent link │
│ TAG ─ Named pointer to commit │
│ │
│ commit ─┬─► tree ─┬─► blob (file1.txt) │
│ │ ├─► blob (file2.txt) │
│ │ └─► tree (subdir/) ─► blob │
│ │ │
│ └─► parent commit │
│ │
└─────────────────────────────────────────────────────────┘
Configuration
Essential Setup
# Identity (required)
git config --global user.name "Your Name"
git config --global user.email "email@example.com"
# Editor
git config --global core.editor "code --wait"
# Default branch
git config --global init.defaultBranch main
# View all settings
git config --list
git config --global --list
Useful Aliases
git config --global alias.st status
git config --global alias.co checkout
git config --global alias.br branch
git config --global alias.ci commit
git config --global alias.lg "log --oneline --graph"
File States
┌─────────────────────────────────────────────────────────┐
│ FILE LIFECYCLE │
├─────────────────────────────────────────────────────────┤
│ │
│ Untracked ──────────────────────────────────────► │
│ │ │
│ │ git add │
│ ▼ │
│ Staged ─────────────────────────────────────────► │
│ │ │
│ │ git commit │
│ ▼ │
│ Committed/Unmodified ───────────────────────────► │
│ │ │
│ │ edit file │
│ ▼ │
│ Modified ──────► git add ──► Staged ──► Committed │
│ │
└─────────────────────────────────────────────────────────┘
.gitignore Patterns
# Ignore specific file
secret.txt
# Ignore by extension
*.log
*.tmp
# Ignore directory
node_modules/
.cache/
# Negation (don't ignore)
!important.log
# Pattern matching
**/build/ # Any directory named build
doc/**/*.pdf # PDFs in doc subdirectories
Troubleshooting Guide
Debug Checklist
□ 1. Inside repo? → git rev-parse --git-dir
□ 2. Clean state? → git status
□ 3. On right branch? → git branch
□ 4. Files tracked? → git ls-files
Common Issues
| Error | Cause | Solution |
|---|---|---|
| "nothing to commit" | No changes staged | Check git status, use git add |
| "untracked files" | New files not added | git add |
| "Changes not staged" | Modified but not added | git add |
| "detached HEAD" | Checked out commit | git checkout main |
Log Patterns
# Normal add output
# (no output = success)
# Normal commit output
[main abc1234] Your message
2 files changed, 10 insertions(+), 3 deletions(-)
Unit Test Template
#!/bin/bash
# test_git_basics.sh
test_init_works() {
tmpdir=$(mktemp -d)
cd "$tmpdir"
git init
assertTrue "[ -d .git ]"
rm -rf "$tmpdir"
}
test_add_stages_file() {
tmpdir=$(mktemp -d)
cd "$tmpdir"
git init
echo "test" > file.txt
git add file.txt
staged=$(git diff --cached --name-only)
assertEquals "file.txt" "$staged"
rm -rf "$tmpdir"
}
test_commit_creates_history() {
tmpdir=$(mktemp -d)
cd "$tmpdir"
git init
git config user.email "test@test.com"
git config user.name "Test"
echo "test" > file.txt
git add file.txt
git commit -m "test"
count=$(git log --oneline | wc -l)
assertEquals 1 "$count"
rm -rf "$tmpdir"
}
Observability
logging:
level: INFO
events:
- command_executed
- file_staged
- commit_created
- error_occurred
metrics:
- commands_per_session
- staging_patterns
- commit_frequency
- error_types
Best Practices
- Commit Often: Small, focused commits
- Write Clear Messages: What and why
- Review Before Commit:
git diff --staged - Use .gitignore: Keep repo clean
- Don't Commit Secrets: Never!
"Git basics are the foundation of all version control."