I know nothing about RTF files but perhaps you could localise the input record separator (see $INPUT_RECORD_SEPARATOR or $/ in perlvar).

knoppix@Microknoppix:~$ perl -E '
> $text = q{Some txt\lineAnother line\lineLast line of text\line};
> say for do {
>    local $/ = q{\line};
>    open $in, q{<}, \$text or die $!;
>    map { chomp; $_ } <$in>;
>    };'
Some txt
Another line
Last line of text
knoppix@Microknoppix:~$
[download]

I hope this is helpful.