Ruby as a shell in GNU Make

ruby-shell.mk

# Example of using Ruby as the command interpreter for GNU Make

# Set shell to ruby...
SHELL:=ruby

# ...and implicitly pass `-e` (Ruby's "eval" option) prior to the
# command string.
.SHELLFLAGS:=-e

# Tell GNU Make to use a single shell process for all lines in a given recipe.
# Requires GNU Make 3.82 (~August 2010).
.ONESHELL:

all:
	puts 'Hello, World!'
	# Yes, blocks work!
	5.times do
	  puts 'Bye!'
	end