pryrt@debianvm:~$ perl -Mlist::utils -le 'print "OK"' Can't locate list/utils.pm in @INC (you may need to install the list::utils module) (@INC contains: ./blib/lib /home/pryrt/perl5/perlbrew/perls/perl-5.20.3/lib/site_perl/5.20.3/i686-linux /home/pryrt/perl5/perlbrew/perls/perl-5.20.3/lib/site_perl/5.20.3 /home/pryrt/perl5/perlbrew/perls/perl-5.20.3/lib/5.20.3/i686-linux /home/pryrt/perl5/perlbrew/perls/perl-5.20.3/lib/5.20.3 .). BEGIN failed--compilation aborted. pryrt@debianvm:~$ perl -MList::Util -le 'print "OK"' OK pryrt@debianvm:~$ corelist List::Util Data for 2015-09-12 List::Util was first released with perl v5.7.3 #### #!/usr/bin/env perl use warnings; use strict; print "enter sequence and signal end with enter followed by ctrl d\n"; my $sequence = ; chomp $sequence; print "sequence inserted : $sequence\n"; my @trips = unpack("a3" x (length($sequence)-2), $sequence); local $" = ", "; print "unshuffled: (@trips)\n"; use List::Util 'shuffle'; my @shuffled = shuffle(@trips); print "shuffled: (@shuffled)\n"; __END__ #### __RESULTS__ enter sequence and signal end with enter followed by ctrl d GATTACCAT sequence inserted : GATTACCAT unshuffled: (GAT, TAC, CAT, , , , ) shuffled: (, , GAT, TAC, CAT, , )