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)
	# - Running targets.
	# - Changing directories.
	#
	# Lesson Three (lesson_three)
	# - Hiding commands and comments.
	# - Ignoring errors.
	#
	# Lesson Four (lesson_four)
	# - Variables

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.

lesson_two: clean
	# Lesson Two
	#
	# 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 director
	# it was called from, it ignores 'cd'.
	@sleep 1
	@echo
	# To change directory, you must chain commands with '&&'
	# or ';'.
	cd lesson_two; pwd

lesson_three:
	# Lesson Three
	#
	# You can hide the command or comment that is run, by
	# prefixing it with '@'.
	#
	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.

lesson_four:
	# Lesson Four
	#
	# 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.

clean:
	@-rm -rf lesson_two

.PHONY: