Watch/read a growing log file

Question

I have a log file that is constantly growing. How can I watch and parse it via a Ruby script?

The script will parse each new line as it is written to the file and ou

Answer 1

def watch_for(file, pattern)
  f = File.open(file,"r")
  f.seek(0,IO::SEEK_END)
  while true do
    select([f])
    line = f.gets
    puts "Found it! #{line}" if line=~pattern
  end
end

watch_for("g.txt",/ERROR/)

Thanks for the ezpz's idea, using the select method you get get what you want. The select method is listening the IO's stream, read the bytes what comes 'late'.