$ perl -de 1 Loading DB routines from perl5db.pl version 1.25 Editor support available. Enter h or `h h' for help, or `perldoc perldebug' for more help. main::(-e:1): 1 DB<1> $s = '12345' DB<2> x split(/(?<=\d)/, $s) 0 1 1 2 2 3 3 4 4 5 DB<3> q # yup, it works