I/O Direction for Bash

This is a good article on I/O Redirection. I have always been interest to redirect stderr to stdout. So here is it 2>&1

 2>&1
      # Redirects stderr to stdout.
      # Error messages get sent to same place as standard output.
        >>filename 2>&1
            bad_command >>filename 2>&1
            # Appends both stdout and stderr to the file "filename" ...
        2>&1 | [command(s)]
            bad_command 2>&1 | awk '{print $5}'   # found
            # Sends stderr through a pipe.
            # |& was added to Bash 4 as an abbreviation for 2>&1 |.