⚠️ Recipes MUST use tabs, not spaces. This is the #1 Makefile gotcha.

# Makefile
target: dependencies
recipe (MUST be a tab, not spaces)
build:
npm run build
test:
npm test
Run with: make build, make test
First target is the default
make (with no args) runs the first target

# Without .PHONY, if a file named "build" exists,
# make thinks the target is up-to-date and skips it
.PHONY: build test clean deploy
build:
npm run build
test:
npm test
clean:
rm -rf dist node_modules
deploy:
./deploy.sh

Always declare .PHONY for targets that don’t produce files.

# deploy depends on test, which depends on build
deploy: test
	./deploy.sh
test: build
npm test
build:
npm run build
make deploy → runs build, then test, then deploy

# Simple assignment
APP_NAME = myapp
PORT = 3000
Use with $(VAR)
run:
docker run -p $(PORT):$(PORT) $(APP_NAME)
Override from command line
make run PORT=8080
Environment variable (export to subprocesses)
export NODE_ENV = production
Conditional (set only if not already set)
PORT ?= 3000
Shell command output
GIT_SHA := $(shell git rev-parse —short HEAD)
DATE := $(shell date +%Y-%m-%d)
build:
docker build -t $(APP_NAME):$(GIT_SHA) .

= is lazy (evaluated when used). := is immediate (evaluated when defined). Use := for shell commands.

.PHONY: help install dev build test lint clean deploy
Default target — show help
help:
@echo “Available targets:”
@echo ”  install  — Install dependencies”
@echo ”  dev      — Start dev server”
@echo ”  build    — Build for production”
@echo ”  test     — Run tests”
@echo ”  lint     — Run linter”
@echo ”  clean    — Remove build artifacts”
@echo ”  deploy   — Deploy to production”
install:
npm ci
dev:
npm run dev
build:
npm run build
test:
npm test
lint:
npx eslint src/
clean:
rm -rf dist node_modules .next
deploy: build
npx vercel —prod

The @ prefix suppresses printing the command itself (only shows output).

APP_NAME := myapp
TAG := $(shell git rev-parse --short HEAD)
.PHONY: build run stop logs shell
build:
docker build -t $(APP_NAME):$(TAG) .
run:
docker compose up -d
stop:
docker compose down
logs:
docker compose logs -f
shell:
docker compose exec app bash
clean:
docker compose down -v
docker image prune -f

# Each line runs in a separate shell. Use \ for multi-line.
setup:
	@echo "Setting up..." && \
	npm install && \
	cp .env.example .env && \
	echo "Done!"
Conditionals
deploy:
ifeq ($(ENV),production)
@echo “Deploying to production…”
./deploy-prod.sh
else
@echo “Deploying to staging…”
./deploy-staging.sh
endif
Ignore errors with -
clean:
-rm -rf dist
-docker compose down