#!/bin/sed -f 1i\ \ \ \ 
\

s,\&,\&,g
s,",\",g
s,<,\<,g
s,>,\>,g
# You may see two odd-looking characters below when displaying this script
# on-screen; they should be literal backspaces (ASCII 8).
s,_\(.\),\1,g
s,,,g
s,\(.\)\1,\1,g
s,,,g
$a\
\ \ \