My first ruby script (for: http://wolfslittlestore.be/2013/01/looking-for-shell-programming-expert/) Usage in terminal: ./billing.rb < input.txt > output.txt

billing.rb

#!/usr/bin/ruby
require 'date'

reLine1 = Regexp.new(/\[b([\d,]+)h\] (.*)/)
reLine2 = Regexp.new(/scheduled (.*)/)

@@hours = nil
@@title = nil
@@date = nil
@@totalHours = 0

STDIN.each_line { |line|
  match = reLine1.match(line)

  if match
    @@hours = match[1]
    @@title = match[2]
  else
    match = reLine2.match(line)
    if match
      @@date = Date.parse(match[1])
      @@totalHours += @@hours.tr(",", ".").to_f
      
      puts "#{@@date.strftime('%d-%m-%y')}\t#{@@hours}\t#{@@title}"
    end
  end
}

puts "\nTotaal: #{@@totalHours}"

input.txt

[b4h] WORK @ Sample project
scheduled 24 Oct 2012 from 08:00 to 12:00
 
[b3,5h] Sample project
scheduled 5 Nov 2012 from 08:30 to 12:00

output.txt

24-10-12    4	WORK @ Sample project
05-11-12	3,5	Sample project

Totaal: 7.5

Thanks Tim :)
I hope you did this from a learning point of view, I might go with another solution because my own Ruby skills are nonexistant

will also answer to https://gist.github.com/4572970