Mr. Script
Device Management
The command-line tool DevCon.exe provides a ton of functionality.
- By Chris Brooke
- 07/01/2005
One of the best things about scripting is taking control away from the Windows
interface. There's nothing finer than finding some hidden API that exposes the
features of an oft-employed GUI tool. Unfortunately, Microsoft doesn't always
give their tools an API that we can script against. Case in point: Device Manager.
While WMI gives us some power over our physical devices, we don't have an API
that provides Device Manager's powerful capabilities. Nevertheless, (spoken
in my best sinister accent) "ve haf vays of makink it vork!" Microsoft has a
command-line tool called DevCon.exe that you can use to enable, disable, restart,
update, remove and query devices or groups of devices. Wrap that up with the
WScript.Shell object and you have something you can really script with. Alternatively,
you can just put it into a command-line script (.cmd file), but where's the
fun in that?
To get started using this fascinating utility, you must first download it from
here.
(Note: Microsoft states that DevCon is unsupported and not redistributable.
It's intended for use as a debugging and development tool, so you're on your
own. 'Nuff said.)
This page also contains some information to help you use DevCon—which is great,
because it doesn't have an accompanying help file. Now that you've downloaded
it, let's take a look at what it can do.
| Listing
1 |
C:\Devcon\i386>devcon
/?
Device Console Help:
devcon [-r] [-m:\\] [...]
-r if specified will reboot machine after command is complete,
if needed.
is name of target machine.
is command to perform (see below).
... is one or more arguments if required by command.
For help on a specific command, type: devcon help
classfilter |
Allows modification of class filters. |
classes |
List all device setup classes. |
disable |
Disable devices that match the specific
hardware or instance ID. |
driverfiles |
List driver files installed for devices. |
drivernodes |
Lists all the driver nodes of devices. |
enable |
Enable devices that match the specific
hardware or instance ID. |
find |
Find devices that match the specific
hardware or instance ID. |
findall |
Find devices including those that
are not present. |
help |
Display this information. |
hwids |
Lists hardware IDs of devices. |
install |
Manually install a device. |
listclass |
List all devices for a setup class. |
reboot |
Reboot local machine |
remove |
Remove devices that match the specific
hardware or instance ID. |
rescan |
Scan for new hardware. |
resources |
Lists hardware resources of devices. |
restart |
Restart devices that match the specific
hardware or instance ID. |
sethwid |
Modify Hardware IDs of listed root-enumerated
devices. |
stack |
Lists expected driver stack of devices. |
| status |
List running status of devices. |
update |
Manually update a device. |
updateni |
Manually update a device (non interactive). |
|
|
|
Listing 1 shows all of DevCon's commands. By specifying the machine where you
want to run the command (DevCon uses Interprocess communication—IPC—to access
remote computers) and the necessary arguments, you can get DevCon to perform
a host of hardware-related operations. Scroll down to the "More Information"
section of this page to find some examples of how to use these commands.
Where Do I Begin?
As you can see, DevCon.exe provides a lot of functionality. In order to get
a handle on its capabilities, you'll need to play with it for a while. After
all, it took you more than just a couple of minutes to get familiar with Device
Manager, didn't it? And that's a GUI tool! Be prepared to invest some time in
learning how to use DevCon. It will be time well spent.
One suggestion: I'd recommend that you begin by working with the enable
and disable commands—specifically as they relate
to network interface cards.
There. I just gave you a big clue as to what we will be discussing next month.
Geez! It's like having homework all over again, isn't it? And I was doing so
well avoiding that lately.
More Information
Examples for Using DevCon.exe
This first example lists the instances of all devices on the local computer.
You might want to pipe that into a text file for easier viewing; my computer,
for example, had 177 listed.
From the command prompt:
C:\Devcon\i386>devcon find *
From a script:
Set objShell=CreateObject ("WScript.Shell")
objShell.Run "cmd /c devcon find *"
This next example displays the status of each PCI instance.
Command prompt:
C:\Devcon\i386>devcon status @pci\*
Script:
Set objShell=CreateObject ("WScript.Shell")
objShell.Run "cmd /c devcon status @pci\*"
Here's a real gem:
Command prompt:
C:\Devcon\i386>devcon update mydev.inf *pnp0501
Script:
Set objShell=CreateObject ("WScript.Shell")
objShell.Run "cmd /c devcon update mydev.inf *pnp0501"
The above command updates all devices that match hardware ID *pnp0501 with
the best associated driver in mydev.inf. Sure beats drilling through the GUI!
To make it even more script-friendly, DevCon provides a return value to the
script that indicates the status:
"0" = Success
"1" = Restart Required
"2" = Failure
"3" = Syntax Error
Of course, in order to get the return value, we have to assign it to a variable
when we call the Run method of the Shell object:
Set objShell=CreateObject ("WScript.Shell")
iResult=objShell.Run("cmd /c devcon update mydev.inf *pnp0501")
WScript.Echo iResult
About the Author
Chris Brooke, MCSE, is a contributing editor for Redmond magazine and director of enterprise technology for ComponentSource. He specializes in development, integration services and network/Internet administration. Send questions or your favorite scripts to [email protected].