perl pickFromRange.pl [ count [ max | min max ] ]
    pickFromRange [ count [ max | min max ] ]

##</code><code>##

#!/usr/bin/perl -w
use strict;

sub pickFromRange
{
    my( $count, $min, $max )= @_;
    my $range= $max - $min + 1;
    die "pickFromRange: $max - $min + 1 < $count"   if  $range < $count;
    my @pick;
    my %replace;
    while(  0 < $count--  ) {
        my $pick= $min + int( rand($range) );
        my $next= $replace{$pick};
        push @pick, defined($next) ? $next : $pick;
        # push @pick, $replace{$pick} // $pick;
        $next = $replace{$max};
        $replace{$pick}= defined($next) ? $next : $max;
        # $replace{$pick}= $replace{$max} // $max;
        delete $replace{$max--};
        $range--;
    }
    return @pick;
}

my $count=  @ARGV ? shift(@ARGV) : 20;
my( $min, $max )= !@ARGV ? (100,999) : 1==@ARGV ? (1,@ARGV) : @ARGV;

my @pick= pickFromRange( $count, $min, $max );
print "@pick\n";