my $string="/ae/gowtham_langTests/hpgl2/hpgl2/linepath/masters/top2bottom/top2bottom9/top2bott om9.plt1.tiff ";
my $pattern = "/hpgl2/";
if ( $string =~ /\A(.*?)$pattern/ ) {
    print "place: ", length $1, "\n";
}
print "index: ", index( $string, $pattern ), "\n";
__END__
place: 21
index: 21