Home > Articles > Home & Office Computing > Microsoft Windows Desktop

A File as Seen from WMI

If you're a Windows 2000 system administrator interested in automated management, you have probably heard of WMI, Microsoft's scriptable COM-based interface to computer system management. Unfortunately, comprehensible information about WMI is hard to find, especially if you do not have prior scripting experience. In this article, Matthew Lavy gives a simple taste of the world of WMI by showing how you can use it to investigate and manipulate a file in an NTFS filesystem.
This article is excerpted from Windows Management Instrumentation, by Matthew Lavy and Ashley Meggitt.
Like this article? We recommend

Windows Management Instrumentation (WMI) is a technology that ships with all current Microsoft operating systems. It can also be retrofitted to Windows NT, Windows 98, and Windows 95. Compared to Active Directory, the Microsoft Management Console, or even the new Windows Device Driver Model, WMI has received relatively little media attention, yet it has the potential to transform the lives of systems administrators responsible for Windows-based networks. The reason? For the first time, it provides a consistent, comprehensive and scriptable interface to the various components and subsystems that make up a Windows-based computer. Within the WMI world, an entire computer system is seen as simply a set of interconnected objects, each of which yields information about and allows manipulation of the component it represents. Thanks to WMI, a whole load of repetitive, mundane tasks, such as checking Event Logs for certain kinds of events, ensuring that server disks do not become full, archiving old files, and generally monitoring running systems, can all be automated with an easily learnable scripting language such as VBScript.

Over the last few months, an encouraging number of articles have appeared, explaining the concept of WMI, its overall structure, the way objects are related to each other, and the underlying technologies. Others have presented clever scripts that use WMI to perform various types of systems management tasks. However, for a systems administrator who is not too familiar with scripting but who wants to begin learning about WMI, a couple of simple questions are rarely answered—namely, "What is a WMI object?" and "How can I use VBScript to play with a WMI object?"

In this article, adapted from Windows Management Instrumentation (Lavy and Meggitt, New Riders), Matthew Lavy attempts to answer these questions in a hands-on, practical way by focusing on just one type of WMI object—namely, the WMI representation of a file. An exploration of a WMI file object and the way in which it can be interrogated and manipulated from VBScript serves as a down-to-earth introduction to WMI objects and the VBScript needed to interact with them. This article assumes a basic knowledge of VBScript and a general understanding of WMI.

Representing a File in WMI

A file is represented in WMI by a CIM_DataFile object. Every file on a Windows 2000 system is represented by one of these objects. In common with all WMI objects, each CIM_DataFile object can be uniquely identified by a primary key, its Name property. In the case of CIM_DataFile objects, the Name property contains a string value representing the fully-qualified path to the file being represented. For example, the object representing boot.ini, a file that can be found in the C: directory of all standard Windows 2000 machines, has the name "c:\boot.ini".

Using VBScript, you can retrieve a reference to a CIM_DataFile object representing c:\boot.ini with the following code fragment:

Set refFile = GetObject("winMgmts:CIM_DataFile.Name='c:\boot.ini'")

This code tells VBScript to ask the winMgmts service (that is, WMI) to find an object of type CIM_DataFile whose name is 'c:\boot.ini'. In reality, the object is not so much "found" as "created," because CIM_DataFile objects are dynamic: WMI creates them as and when they are needed.

As soon as you have a reference to a CIM_DataFile, it is easy to find out most of that file's vital statistics, because these are exposed as properties of the object. For example, you can find out the size, attributes, and creation, modification, and access dates of boot.ini using this simple code example:

Set refFile = GetObject("winMgmts:CIM_DataFile.Name='c:\boot.ini'")
'output the file's name and size
Wscript.echo "File name is: " & refFile.Name
Wscript.echo "File size is: " & refFile.FileSize & " bytes"
'use conditional execution to report on any set attributes
If refFile.Archive then WScript.echo "The archive bit is set"
If refFile.Hidden then WScript.echo "This file is hidden"
If refFile.System then WScript.echo "This is a system file"
'output date information
Wscript.echo "The file was created on: " & refFile.CreationDate
Wscript.echo "The file was last modified on: " & refFile.LastModified
Wscript.echo "The file was last accessed on: " & refFile.LastAccessed
'tell VBScript we have no more use for the object
Set refFile = Nothing

This is a complete, executable script. Type it into a text editor and save it with a .vbs extension. You can then run it using the Windows Scripting Host, preferably in command-line mode. If the preceding sentence does not mean anything to you, open a command shell and type cscript script.vbs, where script is the name of the file you just saved.

Having retrieved a reference to the WMI object that represents c:\boot.ini, the script extracts information by reading its properties. Most of the information is textual (such as Name) or numerical (such as FileSize) and can be displayed directly using WScript.echo. Note that the Archive, Hidden, and System properties, in contrast, are Boolean: They return either true or false. Although you could type WScript.echo "Archive bit:" & refFile.Archive (and, in this case, cause the script to display Archive bit: false), it's much neater to take advantage of the Boolean nature of the Archive property and use a conditional in the code:

If refFile.Archive then WScript.echo "The archive bit is set"

This code displays The archive bit is set if and only if refFile.Archive returns a value of true. Note that as the last step in the script, you set refFile to the special value of Nothing, telling VBScript that you no longer need a reference to the object and that resources allocated to it can be released.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020