Ruby script to allow the user to choose the world they wish to use with their Minecraft server. It will update the server.properties file accordingly.

gistfile1.rb

#############################################################################
# Minecraft server world selector.                                          #
# Author: Xanthalas               Date: May 2011                            #
#############################################################################

puts "Minecraft server world selector"
puts ""
puts "Available worlds:" 
puts ""

worlds = Array.new
counter = 0

Dir.foreach('.') do |item|
  next if item == '.' or item == '..'

  if File::directory?(item)
      counter += 1
      puts "  #{counter}: #{item}"
      worlds.push item
  end

end

if counter == 0
    puts "No worlds found."
    exit
end

puts ""
puts "Which world do you want to visit?"
worldnumber = gets
worldnumber = worldnumber.to_i - 1

if worldnumber < 0 || worldnumber >= worlds.length
    puts "That world doesn't exist"
    gets
    exit
end

puts ""
puts "Selecting #{worlds[worldnumber]}"
File.rename("server.properties", "server.properties.previous")

outfile = File.new("server.properties", "w")
IO.foreach("server.properties.previous"){|line| 
    line = "level-name=#{worlds[worldnumber]}" if line =~ /^level-name/
    outfile.puts(line)
}
outfile.close
File.delete("server.properties.previous")
puts ""
puts "World selection complete. Enjoy your game!"
puts ""
gets