use strict;
use warnings;

while ( <DATA> ) {
   if ( /(^foo.*bar$)|(^foo)|(bar$)/ ){ 
     print $1 ? "BOTH FOO AND BAR: $_" : 
           $2 ? "ONLY FOO: $_" : "ONLY BAR: $_";
   }
   else { print "NOT EITHER: $_" }
}
__DATA__
foo baz
foo bar
bar
fu bar
fuz
foo on you bar