title: sed charachter to leave a match untouched
body: <p>If I have</p>
  
  <p><code>123456red100green
  123456bee010yellow
  123456usb110orange
  123456sos011querty
  123456let101bottle</code></p>
  
  <p>and I want it to be</p>
  
  <p><code>123456red111green
  123456bee111yellow
  123456usb111orange
  123456sos111querty
  123456let111bottle</code></p>
  
  <p>notice: the first 6 characters don't change,,,,
          the following 6 change,,,,
          also these strings might be anywhere in a file (beginning, end, anywhere)</p>
  
  <p>I want to specify sed to
  1)find 123456
  2)skip the next three characters
  3)replace the next three with 111</p>
  
  <p>The closest I've come to is:
  <code>sed '/s/123456....../123456...111/g'</code>
  I know dots mean anything but I don't know the equivalent on the other side. In short how to command sed to leave characters in a match untouched.
  sorry for having been unclear of what I want please bear with me</p>