$ for i in {1..10}; do ./perl -le'%h=(1..20); print "$]: ",join "-", keys %h'; done;
5.017007: 1-13-5-15-19-9-17-11-7-3
5.017007: 13-19-5-17-9-15-1-7-3-11
5.017007: 13-7-19-15-5-1-11-17-3-9
5.017007: 17-13-3-7-15-1-9-5-11-19
5.017007: 17-9-3-11-7-15-1-19-5-13
5.017007: 19-1-11-5-9-3-15-17-7-13
5.017007: 9-19-3-17-7-11-13-15-1-5
5.017007: 1-11-15-3-19-17-7-13-9-5
5.017007: 19-7-13-1-5-17-9-3-11-15
5.017007: 5-19-9-1-13-17-7-3-15-11
$ for i in {1..10}; do perl -le'%h=(1..20); print "$]: ",join "-", keys %h'; done;
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5
5.012004: 11-3-7-9-17-15-1-19-13-5