Replace key words in a file

gistfile1.rb

# Replaces words in input.txt
# Takes arguments in the format foo='bar'

input = File.open('input.txt', "w")
ARGV.each do |i|
	variable_name = i.to_s.split('=')[0]
	contents = .to_s.split('=')[1]
	input.gsub(variable_name, contents)
end