play_switch.rb

#!/usr/bin/env ruby
# encoding: utf-8

require 'fileutils'

def directories(path = Dir.pwd)
  Dir.entries(path).map do |f|
    expand_path = File.expand_path(f, path)
    expand_path if File.directory?(expand_path)
  end[2..-1].delete_if {|v| v.nil?}
end

SRC_PATH = "/home/admin/bin/play_src/"
BIN_PATH = "/home/admin/bin/"
COMMAND  = "play"

buf = []
directories(SRC_PATH).each do |path|
  buf << path.split(/\//).last
end

version = ARGV.first
unless version then
  puts "Usage: ./play_switch.rb version [#{buf.join(' ')}]"
  exit
end

def remove_symbolic_link
  FileUtils.rm(BIN_PATH + "/#{COMMAND}") if FileTest.exist?(BIN_PATH + "/#{COMMAND}")
end

def create_symbolic_link(version)
  original = SRC_PATH + version + '/' + COMMAND
  link     = BIN_PATH + COMMAND
  FileUtils.symlink(original, link)
end

remove_symbolic_link
create_symbolic_link(version)