use strict;
my $text = <<EOT;
foo this is one example bar
this is a line I don't care about
foo here's another keeper! bar
foo yet another bar
and a line to reject
EOT

while ($text =~/foo(.*?)bar/gs) {
   print "$1\n"; 
}
[download]

Works perfectly well for me. Note that the s modifier that I added to the RE allows your extracted text to extend across multiple lines. I don't know if that will matter to you.