Ruby file watch

fwatch.rb

#!/usr/bin/env ruby
require 'listen'

path = ARGV[0]
abspath = File.expand_path(path)
file_name = File.basename(path)
file_dir = File.dirname(path)

if File.exists?(path)
then
	cmd = ARGV[1] % [path] # e.g. "ftp -u ftp://example.com/file.txt %s"
	puts "Listening for changes to '#{file_name}' in '#{file_dir}'"

	listener = Listen.to(file_dir) do |modified, added, removed|
		if modified.include? abspath
		then
			puts "Executing `#{cmd}`..."
			system(cmd)
		end
	end
	listener.start # non blocking
	sleep
else
	puts "File does not exist"
end