edit multiple regions in the same way simultaneously

 This package is an Emacs minor mode and allows you to edit one occurrence of
 some text in a buffer (possibly narrowed) or region, and simultaneously have
 other occurrences edited in the same way.
 .
 You can also use Iedit mode as a quick way to temporarily show only the
 buffer lines that match the current text being edited. This gives you the
 effect of a temporary `keep-lines' or `occur'. To get this effect, hit C-'
 when in Iedit mode - it toggles hiding non-matching lines.