seek and tell may be useful. There's an example in seek that is almost what you need. I would try something like this (untested):

while (my $line = <$info>) {
    my $next_line_start = tell($info); # save start position of next l
+ine
    if ($line =~ /regex/) {
        do_something_here;
    }
    # reposition at $next_line_start
    seek($info,$next_line_start,0);
}
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Update: removed defined in the while test, as it is included (here, at least) in while magic.