A nice little (very rough and being matured) wrapper for reading output asynchronously in ruby using PTY (built-in PseudoTerminal Library). I plan on expanding on this.

run_proc.rb

# Author :: Christopher Woodall <chris.j.woodall@gmail.com>
# Copyright :: 2011 Christopher Woodall
# License :: MIT License
require 'pty'

# run_proc(proc) runs a psuedoterminal version of a command returning output to a block
# asynchronously as it is produced.
def run_proc(proc)
  # Spawn the PTY process
  PTY.spawn(proc) do |r, w, pid|
    # Loop through the process until the end of file is reached
    # and yeild to the block whenever a line is read
    loop do
      begin
        yield r.readline
      rescue EOFError
        break
      end
    end
  end
end

# Example
run_proc("ruby meow.rb") do |a|
 puts a
end