lib/guard/shell.rb
def eager(command)
      require 'pty'

      begin
        PTY.spawn command do |r, w, pid|
          begin
            $stdout.puts
            r.each {|line| print line }
          rescue Errno::EIO
            # the process has finished
          end
        end
      rescue PTY::ChildExited
        $stdout.puts "The child process exited!"
      end
    end
def eager(command)
      require 'pty'

      begin
        PTY.spawn command do |r, w, pid|
          begin
            $stdout.puts
            r.each {|line| print line }
          rescue Errno::EIO
            # the process has finished
          end
        end
      rescue PTY::ChildExited
        $stdout.puts "The child process exited!"
      end
    end
Eager prints the result for stdout and stderr as it would be written when
 running the command from the terminal. This is useful for long running
 tasks.