$ perl -le ' "abcd" =~ /.{2,}(?{print $&})(*FAIL)/ ' abcd abc ab bcd bc cd $ perl -le ' "abcdefg" =~ /.{2,}(?{print $&})(*FAIL)/ ' abcdefg abcdef abcde abcd abc ab bcdefg bcdef bcde bcd bc cdefg cdef cde cd defg def de efg ef fg $