XXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXX
XXXXXXXXXXXXaaaa
abcdefghijklm%nopqrstuvw%xyz

##</code><code>##

while (<FILE>) {
    if (/aaaa$/) {
        $/ = '%';
        while (<FILE>) {} # I tried it with and without this loop
    }
}