cat ./FILE.html | perl {...}

##</code><code>##

#!/usr/bin/perl -w

#retest.pl
# my feeble attempt to a multi-line RE in Perl

$regexp = shift;
while (<>) {
    print if /$regexp/;
}

##</code><code>##

# ./retest.pl \</\div\>\n\<\/body\> ./FILE.html