Post to IRC channel

IRC.rb

require "socket"

# The irc class, which talks to the server and holds the main event loop
class IRC

    def initialize(params)
        @host = params[:host]
        @port = params[:port]
        @nick = params[:nick]
        @channel = params[:channel]
    end

    def post(msg)
        send("PRIVMSG \##{@channel} #{msg}")
    end

    def send(s)
        # Send a message to the irc server and print it to the screen
        puts "--> #{s}"
        @irc.send "#{s}\n", 0 
    end
    def connect()
        # Connect to the IRC server
        @irc = TCPSocket.open(@host, @port)
        send "USER blah blah blah :blah blah"
        send "NICK #{@nick}"
        send "JOIN #{@channel}"
    end

    def evaluate(s)
        # Make sure we have a valid expression (for security reasons), and
        # evaluate it if we do, otherwise return an error message
        if s =~ /^[-+*\/\d\s\eE.()]*$/ then
            begin
                s.untaint
                return eval(s).to_s
            rescue Exception => detail
                puts detail.message()
            end
        end
        return "Error"
    end

    def handle_server_input(s)
        # This isn't at all efficient, but it shows what we can do with Ruby
        # (Dave Thomas calls this construct "a multiway if on steroids")
        case s.strip
            when /^PING :(.+)$/i
                puts "[ Server ping ]"
                send "PONG :#{$1}"
            when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s.+\s:[\001]PING (.+)[\001]$/i
                puts "[ CTCP PING from #{$1}!#{$2}@#{$3} ]"
                send "NOTICE #{$1} :\001PING #{$4}\001"
            when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s.+\s:[\001]VERSION[\001]$/i
                puts "[ CTCP VERSION from #{$1}!#{$2}@#{$3} ]"
                send "NOTICE #{$1} :\001VERSION Ruby-irc v0.042\001"
            when /^:(.+?)!(.+?)@(.+?)\sPRIVMSG\s(.+)\s:EVAL (.+)$/i
                puts "[ EVAL #{$5} from #{$1}!#{$2}@#{$3} ]"
                send "PRIVMSG #{(($4==@nick)?$1:$4)} :#{evaluate($5)}"
            else
                puts s
        end
    end

    def main_loop()
        # Just keep on truckin' until we disconnect
        while true
            ready = select([@irc, $stdin], nil, nil, nil)
            next if !ready
            for s in ready[0]
                if s == $stdin then
                    return if $stdin.eof
                    s = $stdin.gets
                    send s
                elsif s == @irc then
                    return if @irc.eof
                    s = @irc.gets
                    handle_server_input(s)
                end
            end
        end
    end
end

post_to_irc.rb

#!/usr/local/bin/ruby

require 'socket' 
require 'choice'
require './IRC'

Choice.options do
    header ''
    header 'Specific options:'

    option :host do
      short '-h'
      long '--host=HOST'
      desc 'The hostname of the IRC server (default irc.freeirc.de)'
      default 'irc.freeirc.de'
    end

    option :port do
      short '-p'
      long '--port=PORT'
      desc 'The port to connect to (default 6667)'
      cast Integer
      default 6667
    end

    option :nick do
      short '-n'
      long '--nick=NICK'
      desc 'The nick name (default gist2932976)'
      default 'gist2932976'
    end

    option :channel do
      short '-c'
      long '--channel=CHANNEL'
      desc 'The nick name (default #test)'
      default '#test'
    end

    option :msg do
      short '-m'
      long '--message=MESSAGE'
      long '--msg=MESSAGE'
      desc "The message to post (default 'Hi folks!')"
      default 'Hi folks!'
    end

    option :listen do
      long '--listen'
      desc "Listen to the thread"
      default false
    end

    separator ''
    separator 'Common options: '

    option :help do
      long '--help'
      desc 'Show this message'
    end

    option :verbose do
      short '-v'
      long '--verbose'
      desc 'Enable verbose mode'
    end

    option :version do
      long '--version'
      desc 'Show version'
      action do
        puts "v#{PROGRAM_VERSION}"
        exit
      end
    end
end

puts Choice.choices.inspect if Choice.choices[:verbose]

irc = IRC.new(Choice.choices)  
irc.connect()

irc.post(Choice.choices[:msg])

if Choice.choices[:listen]
  begin
    irc.main_loop()
  rescue Interrupt
  rescue Exception => detail
    puts detail.message()
    print detail.backtrace.join("\n")
    retry
  end
end

This is really cool! My favorite line is line 58 where you determine whether the command was in a channel or a query and generate the proper PRIVMSG target: #{(($4==@nick)?$1:$4)} Nice!

To be honest: The original version v1 is a copy from http://www.dzone.com/snippets/simple-irc-bot-written-ruby