makefile

name	makefile
description	Help with Makefiles - targets, variables, patterns, and best practices
argument-hint	[target or question]
allowed-tools	Read, Glob, Grep, Bash

Help with Makefiles based on $ARGUMENTS.

Makefile Basics

Variables

# Simple assignment (recursive)
CC = gcc

# Immediate assignment
CC := gcc

# Conditional (set if not defined)
CC ?= gcc

# Append
CFLAGS += -Wall

Automatic Variables

Variable	Meaning
$@	Target name
$<	First prerequisite
$^	All prerequisites
$*	Stem (matched by %)
$(@D)	Directory of target
$(@F)	File part of target

Pattern Rules

# Compile .c to .o
%.o: %.c
	$(CC) $(CFLAGS) -c $< -o $@

# Any file from template
%: %.tmpl
	envsubst < $< > $@

Common Patterns

.PHONY: all clean test build

# Default target
all: build

# Build with dependencies
build: $(OBJECTS)
	$(CC) $(LDFLAGS) -o $@ $^

# Clean generated files
clean:
	rm -rf build/ *.o

# Run tests
test:
	go test ./...

# Help target
help:
	@grep -E '^[a-zA-Z_-]+:.*?## ' $(MAKEFILE_LIST) | \
		awk 'BEGIN {FS = ":.*?## "}; {printf "%-15s %s\n", $$1, $$2}'

Best Practices

• Use .PHONY for non-file targets
• Use @ prefix to suppress command echo
• Use - prefix to ignore errors
• Define clean target
• Use variables for repeated values