.gitignore

# ===== Basic syntax =====
# Comments start with #
# Blank lines are ignored
# One pattern per line

# Match a file:
secrets.json

# Match anywhere:
*.log

# Match a directory (trailing slash):
node_modules/

# Match anywhere in tree:
**/*.log

# Anchor to root (leading slash):
/build/             # only ./build, not src/build

# Negate (un-ignore):
*.log
!important.log      # include this one anyway

# ===== Glob patterns =====
*.tmp               # any .tmp
*[Cc]ache*          # match Cache or cache
**/temp/**          # any 'temp' folder at any depth
[abc].txt           # a.txt or b.txt or c.txt
?ar                 # bar, car, ear, ...

# ===== Per-directory .gitignore =====
# Each directory can have its own .gitignore.
# Inner rules override outer rules.

# src/.gitignore:
*.local.ts

# ===== Common patterns =====
# Node:
node_modules/
.npm/
.yarn/
.pnpm-store/
dist/
build/
coverage/
*.log
.env
.env.*
!.env.example

# Python:
__pycache__/
*.pyc
*.pyo
.venv/
venv/
.pytest_cache/
.coverage
*.egg-info/
build/
dist/

# Java / Maven / Gradle:
target/
build/
*.class
.gradle/
.idea/
*.iml

# macOS / IDE / OS:
.DS_Store
Thumbs.db
.vscode/
!.vscode/extensions.json
!.vscode/settings.json
.idea/
*.swp
*.swo

# ===== Global gitignore (per user) =====
git config --global core.excludesfile ~/.gitignore_global
# Add OS / editor files there so every project gets them without explicit listing.

# ===== Already-tracked files =====
# .gitignore does NOT affect files already tracked.
# To untrack a file but keep it locally:
git rm --cached secret.json
git commit -m 'untrack secret.json'

# Then add to .gitignore.

# ===== Force-add an ignored file =====
git add -f forced-file.log

# ===== Check what is ignored / why =====
git check-ignore -v dist/main.js
# .gitignore:5:dist/  dist/main.js

git status --ignored

# ===== Templates =====
# GitHub provides good templates: github.com/github/gitignore
# Toptal has gitignore.io for combined .gitignore generation.

# ===== Patterns to internalise =====
# - .env in .gitignore; .env.example committed
# - node_modules / build / dist / coverage / .DS_Store etc.
# - Commit a base .gitignore on day 1; iterate
# - Use git check-ignore when surprised

# ===== Pitfalls =====
# - Committing .env, then 'gitignoring' it (still in history; rotate secrets!)
# - Forgetting trailing slash on directories -> partial match
# - Negation on a file inside an ignored dir -> doesn't work (parent rule wins)
# - Editor files (.idea, .vscode) without selective inclusion -> teammates fight

node_modules/
.env
dist/
*.log
.DS_Store