print "$-[0]: $1" while $a =~ m[(?:.{4})*(?=(aa..))]g;; 0: aawx 404: aawx 405: aadz 481: aadz print "$-[0]: $1" while $a =~ m[^(?:.{4})*(?=(aa..))]g;; 0: aawx print "$-[0]: $1" while $a =~ m[(?:.{4})*(?=(gg..))]g;; 0: gghn 208: gghn 211: ggyj 955: ggyj print "$-[0]: $1" while $a =~ m[^(?:.{4})*(?=(gg..))]g;; 0: gghn