title: removing multibyte characters from a file using sed
body: <p>i need to remove all multibyte characters from a file, i dont know what they are so i need to cover the whole range.</p>
  
  <p>I can find them using grep like so:
  grep -P "[\x80-\xFF]" 'myfile'</p>
  
  <p>Trying to do a simular thing with sed, but delete them instead.</p>
  
  <p>Cheers</p>