Thanks for the help, syphilis.

In the typical win32 way, things don't seem to be behaving as specified. Appending the dollar sign gives an error, and using the computer name seems to return a domain SID.

I'm working on a system that's not a member of a domain, with username "shop_user" and "system name" is "SHOP_02". FWIW, I'm testing on Windows XP systems with ActiveState Perl 5.8.8.

use strict;
use warnings;

use Win32::Security::SID;

my @SIDTYPE = qw(
    ERROR
  SidTypeUser
  SidTypeGroup 
  SidTypeDomain
  SidTypeAlias
  SidTypeWellKnownGroup
  SidTypeDeletedAccount
  SidTypeInvalid
  SidTypeUnknown
  SidTypeComputer
  SidTypeLabel
);


my ( $system, $account );

$account = Win32::LoginName;
$system  = Win32::NodeName;

GetSID( $system, "$system\\$account");
GetSID( $system, $account);

GetSID( $system, $system);
GetSID( $system, "$system\\");
GetSID( $system, "\\$system");
GetSID( $system, "SYSTEM\\$system"); 
GetSID( $system, "\$$system"); 
GetSID( $system, "$system\$"); 
GetSID( $system, "$system\\\$"); 


sub GetSID {
    my $system = shift;
    my $account = shift;
    my $domain = shift;
    
    no warnings 'uninitialized';
    my ( $sid, $sidtype );

    Win32::LookupAccountName( $system, $account, $domain, $sid, $sidty
+pe );

    my $sidstring = Win32::Security::SID::ConvertSidToStringSid( $sid 
+); 
    print 
        "\n",
        "$system - $account - $domain\n",
        "SID: $sidstring\n",
        "SIDTYPE: $SIDTYPE[$sidtype]\n";
    ;

}
[download]

Here are the results:

SHOP_02 - SHOP_02\shop_user - SHOP_02
SID: S-1-5-21-1957994488-963894560-725345543-1004
SIDTYPE: SidTypeUser

SHOP_02 - shop_user - SHOP_02
SID: S-1-5-21-1957994488-963894560-725345543-1004
SIDTYPE: SidTypeUser

SHOP_02 - SHOP_02 - SHOP_02
SID: S-1-5-21-1957994488-963894560-725345543
SIDTYPE: SidTypeDomain

SHOP_02 - SHOP_02\ -
SID:
SIDTYPE: ERROR

SHOP_02 - \SHOP_02 - SHOP_02
SID: S-1-5-21-1957994488-963894560-725345543
SIDTYPE: SidTypeDomain

SHOP_02 - SYSTEM\SHOP_02 -
SID:
SIDTYPE: ERROR

SHOP_02 - $SHOP_02 -
SID:
SIDTYPE: ERROR

SHOP_02 - SHOP_02$ -
SID:
SIDTYPE: ERROR

SHOP_02 - SHOP_02\$ -
SID:
SIDTYPE: ERROR
[download]