Makefile

###
# Usage:
#
# Download this file and start by running 'make'. Then run
# each target listed, 'make lesson_one', 'make lesson_two',
# etc.
#

introduction:
	# Introduction:
	#
	# Lesson One (lesson_one)
	# - Makefiles and makefiles.
	# - Default target.
	#
	# Lesson Two (lesson_two)
	# - Targets (tasks) and prerequisite targets (tasks).
	#
	# Lesson Three (lesson_three)
	# - Running targets.
	# - Changing directories.
	#
	# Lesson Four (lesson_four)
	# - Hiding commands and comments.
	# - Ignoring errors.
	#
	# Lesson Five (lesson_five)
	# - Variables
	#
	# Lesson Six (lesson_six)
	# - Shell commands.
	# - $$(shell [command])
	#
	# Lesson Seven (lesson_seven)
	# - Tasks and their association with files
	#	  and directories. on disk.
	# - .PHONY
	#
	# Note: lesson tasks are aliased to l#, example:
	#
	#	make l1 # is the same as make lesson_one

lesson_one:
	# Lesson One
	#
	# The standard file naming for 'make' is Makefile, alhtough
	# I've often seen 'makefile' as well. The accepted extension
	# is '.mk', often used for include files - I'll cover includes
	# later.
	#
	# The default target, that is to say, the target that is
	# run when 'make' is executed without a target, will always
	# be the first target in the 'Makefile'. In this file,
	# 'introduction' is the default target.

l1: lesson_one

lesson_two:
	# Lesson Two
	#
	# Make targets, often called "tasks" (especially by me), are
	# the basic break down of make and running actions. If you've
	# ever built anything on from source on a linux system, you've
	# run some basic tasks like "make install" or "make test".
	#
	# At it's core a Makefile is simply a list of targets that
	# perform requested actions.
	#
	# build:
	#	go build -o myprog myprog.go
	#
	# install:
	#	cp myprog /home/user/go/bin
	#
	# clean:
	#	rm myprog
	@sleep 1
	@echo
	# Make targets can also request that prerequisite targets are run
	# prior to running the requested target. In the above, it might be
	# nice to run 'build' before running install. In doing so, we
	# ensure that we have something to install.
	#
	# build:
	#	go build -o myprog myprog.go
	#
	# install: build
	#	cp myprog /home/user/go/bin
	#
	# Additionally, when running 'make install', it will only attempt
	# to install 'myprog' if the build task successfully completes.

l2: lesson_two

lesson_three: _clean
	# Lesson Three
	#
	# Make runs commands, one after another.
	pwd
	mkdir lesson_two
	@echo
	cd lesson_two
	pwd
	@echo
	# Make's commands are always run from the root directory
	# it was called from, it ignores 'cd'.
	@sleep 1
	@echo
	# To change directory, you must chain commands with '&&'
	# or ';'.
	cd lesson_two; pwd

l3: lesson_three

lesson_four:
	# Lesson Four
	#
	# You can hide the command or comment that is run, by
	# prefixing it with '@'.
	@echo
	echo "This command will be shown, and then it's output will be shown."
	@echo
	@echo "This command is prefixed with '@', only it's output will be shown."
	@echo
	@sleep 1
	# This comment will be shown, but comments prefixed with '@' won't be.
	#
	#  Example: '@#' hidden comment.

l4: lesson_four

lesson_five:
	# Lesson Five
	#
	# Variable's are set and called, much like in bash, the difference
	# being that aside from being prefixed with a dollar sign ($$), the
	# variable must wrapped in parentheses - e.g. "$$(FOO)".
	#
	#   FOO=bar   # setting
	#   $$(FOO)    # calling
	#
	# Additionally, variables can only be set external to targets.

l5: lesson_five

lesson_six:
	# Lesson Six
	#
	# Because make runs basic shell command already you can simply use
	# standard shell in many cases.
	@echo
	echo "My host `hostname`"
	@echo
	# To easily insert the output of a shell command, use $$(shell [cmd]).
	# This is useful when wanting to do things like set make variables or
	# comment text to the output of a shell command.
	#
	# Variable's example:
	#
	#   TEST_FILES=$$(shell find . -type f -name "*_test.js")
	#
	# Again, variables can only be set external to targets.
	#
	# Example using '$$(shell hostname)'
	#
	# This comment has the output of a shell command
	#
	#	--> host: $(shell hostname)

l6: lesson_six

lesson_seven: _clean
	# Lesson Seven
	#
	# Make task names are designed to match file and directory locations
	# on disk.
	@sleep 1
	#
	# In this example, 'lesson_seven.out' will only be generated if
	# it does not already exist.
	#
	# lesson_seven.out:
	#	 echo "lesson seven" > lesson_seven.out
	@echo
	make lesson_seven.out
	@echo
	@sleep 1
	#
	# Now if we re-run the same task, make will inform us that everything
	# is up to date and therefore nothing to be done.
	@echo
	make lesson_seven.out
	@echo
	@sleep 1
	# The same is true for directories as well, the following will only
	# create 'public/assets' if it doesn't already exist.
	#
	# public/assets:
	#	mkdir public/assts
	@sleep 1
	#
	# Make provides a way to turn off this 'feature', through a task called
	# .PHONY. To use this, there are two steps. First create a .PHONY task
	# somewhere in your Makefile -- by convention, this tends to be the last
	# task in the file. Second, either include .PHONY as a prerequisite task of your
	# task, or your task as a prerequisite task of .PHONY.
	@sleep 1
	#
	# Example;
	#
	# mytask: .PHONY
	#	echo "my action"
	#
	# .PHONY
	#

l7: lesson_seven

lesson_seven.out:
	echo "lesson seven" > lesson_seven.out

# All tasks below this point are helper tasks for this tutorial.
####
_clean:
	@-rm -rf lesson_two
	@-rm -rf lesson_six.out


.PHONY: