./1.permute.pl : permutations for 851:
  8,5,1
  8,1,5
  5,8,1
  5,1,8
  1,8,5
  1,5,8
$ cat 1.permute.pl
#!/usr/bin/perl -w
use 5.011;

use Algorithm::Combinatorics qw/permutations/;

die "Usage : $0 number" unless scalar @ARGV;

my @digits = split //, $ARGV[0];

my $iter = permutations( \@digits );
print "$0 : permutations for $ARGV[0]:\n";
while ( my $p = $iter->next ) {
  print "  " . join( ",", @$p ) . "\n";
}
$