my $search = 'is today saturd or sunday?';
my $record = 'saturday';
my $pattern;
my @chars;
my @patterns;
my $len = 4;

@chars = split(//, $search);
for(my $i = 0; $i <= length($search) - $len; $i++)
 {
   push(@patterns, quotemeta(join('', @chars[$i .. $i + $len - 1])));
 }
$pattern = '(?:'.join('|', @patterns).')';
if($record =~ /$pattern/)
 {
   print "Match with pattern $pattern\n";
 }