#!perl -w
use strict;

my $params = &GetParameters();
my @dirs = @{ $params->{dir} };
my @file = @{ $params->{file} };
print "\nDIRS:\n\t";
print join("\n\t", @dirs);
print "\nFILES:\n\t";
print join("\n\t", @file);
# and so on

sub GetParameters {
  my @allowedParams = qw(file dir);
  die &PrintUsage() unless @ARGV;
  my $params = {}; # shell contain parameters

  foreach (@ARGV){
    my ($key, $val) = split(/\=/, $_, 2); # split up by the first =
 
    # test if $key is a valid parameter
    unless ($key =~ s/^\-\-//) { # must start with --
        die &PrintUsage( "Error: invalid param --$key");
    }
    unless ( grep {lc($key) eq lc($_)} @allowedParams){
        die "Error: param $key not allowed\n";
    }
       
    # maybe do some checks if $val is existing
#    ....
    # add param to hashreference $params
    push (@{ $params->{$key} }, $val);

  } # for
  return ($params);
} # GetParameters

# Added &PrintUsage; thx to [mull]

sub PrintUsage{
    my $msg = shift || '';
    return (<<USAGE);
$msg:

$0 --dir=/dir1/sdir2 --dir=/dir2/sdir2 --file=README.txt
USAGE
    ;
}

##</code><code>##

C:\TEMP\test>testParameters.pl --dir=/dir1/sdir2 --dir=/dir2/sdir2 --file=README.txt

DIRS:
        /dir1/sdir2
        /dir2/sdir2
FILES:
        README.txt
C:\TEMP\test>