cowsay.rb

def has_arg(arg)
  ARGV.include? arg
end

text = ARGV[0]

lines = text.scan(/.{0,40}(?:\b|$)/).map{|l| l.strip }
lines = (lines[-1] == "" ? lines[0...-1] : lines)
longest = lines.map{|l| l.length}.max
lines.map!{|l| l+ (" " * (longest - l.length))}

def bubble(lines)
    if (lines.count == 1)
        if has_arg("--think")
            "( #{lines[0]} )"
        else
            "< #{lines[0]} >"
        end
    else
        borders = [ "/ $ \\",
                    "| $ |",
                    "\\ $ /"]
        count = lines.count
        lines.each.with_index.map{|line, index|
            format = (index == count-1 ? 2 : (index == 0 ? 0 : 1) )
            borders[format].gsub("$", line)
        }.join("\n")
    end
end

def eyes(args = ARGV)
    moods = {
        "--mad" => "oO",
        "--wink" => "o-",
        "--squint" => "><",
        "--sleep" => "--",
        "--dead" => "XX",
        "--alarm" => "OO"
    }

    args.reverse.each{|arg| return moods[arg] if moods.has_key?(arg) }
    "oo"
end

tongue = " "
tongue = "U" if has_arg "--mad"

link = "\\"
link = "o" if has_arg "--think"

puts """ #{ '_' * (longest+2)}
#{bubble lines}
 #{ '-' * (longest+2)}
        #{link}   ^__^
         #{link}  (#{eyes})\\_______
            (__)\\       )\\/\\
             #{tongue}  ||----w |
                ||     ||"""

Usage:

ruby cowsay.rb "Moo!" --mad

 ______
< Moo! >
 ------
        \   ^__^
         \  (oO)\_______
            (__)\       )\/\
             U  ||----w |
                ||     ||