>perl -wMstrict -le
"my $str = qq{foo data } x 5;
 print $str;
 ;;
 print qq{start of 'data' at $-[1]} while $str =~ m{ (data) }xmsg;
"
foo data foo data foo data foo data foo data
start of 'data' at 4
start of 'data' at 13
start of 'data' at 22
start of 'data' at 31
start of 'data' at 40