use strict;
use warnings;

my @vars = ('quit','quirly cat', 'cat queue','granit');

print ("any string 'qu' followed by 'it'\n");
foreach (@vars) {
    if ($_ =~ /qu(?=it)/) { print ("found <$_>\n"); }
    else { print ("no match for <$_>\n"); }
}

print ("\nany string 'qu' not followed by 'it'\n");
foreach (@vars) {
    if ($_ =~ /qu(?!it)/) { print ("found <$_>\n"); }
    else { print ("no match for <$_>\n"); }
}