$ perl -E 'my @range = ( 20170701 ... 20170704 ); say for @range;'
20170701
20170702
20170703
20170704

#!/usr/bin/perl

use warnings;
use strict;

use DateTime;

sub getDatetime {
    my $str = shift;
    my @a = split(/\./, $str);
    my $dt = DateTime->new(
      year       => $a[2],
      month      => $a[1],
      day        => $a[0],
      time_zone  => 'Europe/Berlin');
   return $dt;
}

my $start = getDatetime("1.7.2017");
my $end = getDatetime("4.7.2017");
my $step = DateTime::Duration->new(days => 1);
my @ergebnisliste = ();
while ($start->epoch() <= $end->epoch()) {
    push(@ergebnisliste, $start->day() . "." . $start->month() . "." . $start->year());
    $start->add($step);
}
for my $i (@ergebnisliste) {
    print "$i\n";
}

use Class::Date 'date';

my $date = date('2000-02-25');

while ($date <= '2000-03-04') {
        say $date;
        $date += '1D';
}