Windows Administration

CMD.EXE

Configuration

• Enable file / path extension (see help cmd):

HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor\CompletionChar     <-- 09 (tab)
HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor\PathCompletionChar <-- 09 (tab)

• Command Extension are enabled by default

HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor\EnableExtensions

• Delayed expansion is not enabled by default:

HKEY_CURRENT_USER\Software\Microsoft\Command Processor\DelayedExpansion

Other useful config tools:

DOSHere

Open a cmd prompt by right clicking on any directory in windows explorer

Device Management

View and Delete Unused Devices

Open a cmd.exe console:

set devmgr_show_nonpresent_devices=1
devmgmt.msc

In the Device Management Console, select show hidden devices. Unused devices are grayed out.

Convert Logical Drive Letter to PhysicalDrive

The following C program illustrates what Win32 API to use to convert a logical drive letter like C: to the corresponding PhysicalDrive specification.

#include <stdio.h>
#include <w32api/wtypes.h>
#include <w32api/ddk/ntdddisk.h>

int main()
{
    HANDLE hDeviceHandle = NULL;

    char drive[] = {'\\', '\\', '.', '\\', 'A', ':', 0};
    DWORD driveMask = GetLogicalDrives();

    for(int i = 0; i < 26; i++)
    {
        drive[4] = 'A' + i;
        printf("Drive: %s\n", drive);
        hDeviceHandle = CreateFile(drive , 0, 0, NULL,
        OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL, NULL);
        if (hDeviceHandle != (HANDLE)-1)
        {
            STORAGE_DEVICE_NUMBER sdn;
            DWORD returned;
            if (DeviceIoControl(
                hDeviceHandle,IOCTL_STORAGE_GET_DEVICE_NUMBER,NULL ,0,&sdn,sizeof(sdn),&returned,NULL));
            {
                printf("\tDevice type: %d number: %d partition: %d\n",sdn.DeviceType,
                sdn.DeviceNumber, sdn.PartitionNumber);
                if(sdn.DeviceType == 7)
                    printf("\t-->\t\\\\.\\PhysicalDrive%d\n",sdn.DeviceNumber);
            }
        }
    }

    return 0;
}

Compile with:

% gcc logicalToPhysicalDrive.cpp

Example of output:

Drive: \\.\C:
        Device type: 7 number: 0 partition: 1
        -->     \\.\PhysicalDrive0

Regedit

Command-line

Using regtool (cygwin):

regtool /s registry_file.reg                     ;Silent merge registry file (no user confirmation)

Using reg.exe (windows):

• See http://ss64.com/nt/regedit.html
• See http://ss64.com/nt/reg.html

;Silent merge
regedit /s registry_file.reg                      

;Create a global USER environment variable (persistent)
SET MYROOT="%CD"
echo Setting global USER Environment variable to %MYROOT%
reg add HKCU\environment /v MYROOT /t REG_SZ /d %MYROOT% /f

Regedit .reg File Format

See also Microsoft's reference page, here, here, here and on Wikipedia.

See also regtool chapter on Cygwin page.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\Setup]
@=dword:00000000
"SetupType"=dword:00000000
"CmdLine"="setup -newsetup"
"SystemPrefix"=hex:c5,0b,00,00,00,40,36,02

; Comments are created with a semi-colon

; Delete a value by assigning a minus to it
"SetupType"=-

; Delete a key by preceding the name with a minus sign
[-HKEY_LOCAL_MACHINE\SYSTEM\Setup]

The header line indicates the version and can be either

 Windows Registry Editor Version 5.00   for Windows 2000, Windows XP, and Windows Server 2003
 REGEDIT4                               for Windows 98 and Windows NT 4.0 (but is also accepted in 2000, XP or 2003)

Network

Detect Network Environment Change

The following VBS script can be used to detect automatically when a network cable is connected or disconnected ("network cable unplugged"), as in [1]. Some explanations at [2], and more on [3].

Use MSNdis_StatusMediaDisconnect to detect when a cable is unplugged.

Set colMonitoredEvents = GetObject("winmgmts:root\wmi")._
     ExecNotificationQuery("Select * from MSNdis_StatusMediaConnect")
Do
     Set strLatestEvent = colMonitoredEvents.NextEvent
     WScript.Echo "Connected! Do something here"
     ' enable the line below if you want to exit after the first event.
     ' Exit Do
Loop

Same script a bit improved in order to limit detection to some specific adapter:

Set colMonitoredEvents = GetObject("winmgmts:root\wmi")._
     ExecNotificationQuery("Select * from MSNdis_StatusMediaConnect" _
        & " WHERE InstanceName = '3Com 10/100 Mini PCI Ethernet Adapter'")
Do
     Set strLatestEvent = colMonitoredEvents.NextEvent
     WScript.Echo "Connected! Do something here"
     ' enable the line below if you want to exit after the first event.
     'Exit Do
Loop

Rename / Delete locked files using Registry

This uses a registry data called PendingFileRenameOperations in key [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager]. This data is a REG_MULTI_SZ. The syntax is as follows:

\??\source file
!\??\target file

To delete a file, target file must be the null string, i.e. 00 00. For instance the registry file below can be used to delete a file named c:\TEMP\Kill-ME.eXe.

REGEDIT4

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager]
"PendingFileRenameOperations"=hex(7):5C,3F,3F,5C,63,3A,5C,54,45,4D,50,5C,4B,69,6C,6C,2D,4D,45,2E,65,58,65,00,00,00

Another way is to use the windows program reg.exe.

Tips / How-tos

Re-Enable Hibernate Option (Vista)

On Vista, Hibernation is disabled after running the disk cleanup wizard and removing the hibernate files. To re-enable (see [4]):

• Go to the command prompt icon in the Start menu under Accessories and right click the icon: click “Run as administrator”.
• Paste: “powercfg.exe /hibernate on” and hit Enter and also paste “powercfg -h on” and hit enter just to be safe.
• Open Control Panel and type in “Hibernate” in the Search.
• Click “Turn hibernation on or off”
• Click “Change advance power settings”
• Scroll to and expand the “Sleep” option.
• Select “Off” to the “Allow hybrid sleep” option.
• Scroll to and expand the “Power buttons and lid” option.
• Select “Hibernate” for the “Sleep button action” option.
• Select “Hibernate” for the “Start menu power button” option.

Enable Login Verbose Status

Reference: [5]

Windows Registry Editor Version 5.00
 
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System]
"VerboseStatus"=dword:00000001

Patch file version data

Some windows file have a specific record that stores release information on that specific file (like file version, company name, etc ). One can see this record by using the NT Explorer → right click → properties → Version panel. It is quite easy to change the content of this record by using an Hex Editor such as UltraEdit. Just look for either of the hex string below in the file:

560053005F00560045005200530049004F004E005F0049004E0046004F00 // V.S._.V.E.R.S.I.O.N._.I.N.F.O.
460069006C006500560065007200730069006F006E                   // F.i.l.e.V.e.r.s.i.o.n.

Note that the version number (file version) given at the top of the Version panel is actually coded in hex. The example below gives a file version 1.2.3.4.

xx xx xx xx xx xx xx xx xx xx 56 00 53 00 5F 00 // xxxxxxxxxxV.S._.
56 00 45 00 52 00 53 00 49 00 4F 00 4E 00 5F 00 // V.E.R.S.I.O.N._.
49 00 4E 00 46 00 4F 00 xx xx xx xx xx xx xx xx // I.N.F.O.xxxxxxxx
xx xx xx xx 02 00 01 00 04 00 03 00 xx xx xx xx // xxxx........xxxx

Shut down / lock windows from command-line

Using rundll32.exe (see [6]):

rundll32.exe user32.dll,LockWorkStation

Another one:

rundll32.exe shell32.dll,SHExitWindowsEx [0|1|2|4|8]
:: 0: logoff, 1: shut down, 2: reboot, 4: forced shutdown, 8: powers down the machine

Reset Administrator password from Linux

• Install package chntpw (from universe)
• Edit .../Windows/System32/config/SAM file:

cd .../Windows/System32/config
chntpw -l SAM                        # List available users
chntpw -u SysAdmin SAM               # Edit user 'SysAdmin'

• Don't forget to umount Windows partition.

Open Issue

Reduce volume size after updates and service packs

Particularly true for Windows Vsta. Ideas:

• Can we use sysprep tool?

Troubleshoot

Windows 7 Boot Issues

See Windows 7 boot troubleshooting.

Network Connection Folder is Empty

Reference [7]

• Open registry editor, and go to key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Network,
• Delete the binary value Config,

There is no normally no need to restart the computer.

The trust relationship between this workstation and the primary domain failed

Relevant links:

• How to fix: [8]
• KB on netdom.exe [9]
• Test relationship with nltest.exe [10]
• NT Gatekeeper: Finding Out Where NT Stores a Machine Account’s Credentials
• Prevent the problem [11]

The root cause is a desync between the machine account password on the computer locally (known as a local secret) and the computer's computer account object on the Windows domain controller. By default, each windows machine changes the local machine account password every 30 days, and replicates this change to the domain controller. The authentication process keeps the current password and previous password. A desync may occur if the machine is reset to a previous state beyond two password changes.

To fix: Use netdom.exe to resync the machine account passwords[12] (need special privilege on DC).

To prevent the problem from happening, edit the following keys in HKLM\SYSTEM\CurrentControlSet\Services\NetLogon\Parameters [13]:

• MaximumPasswordAge
• DisablePasswordChange
• ScavengeInterval