knoppix@Microknoppix:~$ perl -MList::Util=shuffle -Mstrict -wE '
my @lc  = shuffle q{a} .. q{z};
my @uc  = shuffle q{A} .. q{Z};
my @dig = shuffle q{0} .. q{9};
my @oth = shuffle qw{ ! " £ $ % ^ & * _ - + = @ ~ };
my @all = \ ( @lc, @uc, @dig, @oth );

my @order = ( 0 .. 3 );
push @order, int rand 4 for 1 .. 4;
@order = shuffle @order;

my $passwd = q{};
$passwd .= $all[ $_ ]->[ rand @{ $all[ $_ ] } ] for @order;

say $passwd;'
E5yR=$%£
knoppix@Microknoppix:~$ 

##</code><code>##

...
$passwd .= splice @{ $all[ $_ ] }, rand @{ $all[ $_ ] }, 1
   for @order;
...