How to Gather Data for FILExt

Note: This applies to those running Windows Vista, Windows XP, Windows ME, or Windows 2000 only. Please do not continue if you use an operating system other than Windows Vista, Windows XP, Windows ME, or Windows 2000. The necessary system commands do not exist in Windows 95, 98, or 98SE.

Further Note: If you have the Google Desktop installed, see here for a much easier way to do this and have FILExt on your desktop at the same time.

By running a small batch file and sending FILExt the output from that file you can help keep the FILExt database up to date and complete. Please's how.

First, download the batch file called filext_filetype.bat from this site. The file is 507 bytes in size. To get the file right click on the link below and choose the option to Save Target As... (or, Save Link As... if using FireFox). FILExt suggests saving the file to the desktop as that puts the output file on the desktop as well and makes finding it easier. When you are finished you can safely delete both the batch file and its output file. (Note: Some firewall programs will ask if you trust this script. So long as you got it from this page and have verified its contents with the listing below the batch file is safe.)


If you wish to see what the commands in the batch file are, feel free to open the file in any text editor and look at it. Please do not make any changes to the file. For reference, here is a copy of what the file should have in it...

    Echo OFF
    assoc > filext_submission_output.txt
    Echo ---------- >> filext_submission_output.txt
    ftype >> filext_submission_output.txt
    Echo Thank you. The output file has been created and
    Echo named filext_submission_output.txt and it should
    Echo be in the same place where you saved this batch
    Echo file. All that is left now is to send that file
    Echo to FILExt. Attach it to an E-mail sent to the
    Echo address:
    Echo The E-mail subject should be: Submission
    Echo Thank you.

To obtain the output, please simply double click on the batch file. A command prompt window should flash open and in very little time display the text message that says the processing is finished and that you should then mail the output to FILExt at a specific address. The output file should be in the same folder as the batch file (or on the Desktop if you followed the suggestion to put the batch file there).

How you attach the output file to a mail message will depend on your mail client program. FILExt can't guide you there; please use the help for your mail client if you do not know how. The address to send the file to is . Place one word in the Subject of the E-mail: Submission. Please do not ask questions or send any other mail or file to that address; it will be filtered and only mail with text attachments with the correct name will be sent on to FILExt, everything else will be automatically discarded (since this address is exposed to collection robots on this page and in the batch file, FILExt anticipates recieving significant amounts of spam and malware at the address making the automatic discarding of such material mandatory).

You are certainly able to look at the file in a text editor before sending it. But, if you do please do NOT save the file in the text editor; just exit without saving and send the file as the batch file created it. If you save the file while in the text editor the lines may have wrapped and it will be saved that way. This makes the file useless and it will just be discarded if it has wrapped lines. That wastes your time and mine.

If you are worried about privacy, please understand that during submission your E-mail address can be associated with the submission and so someone could associate all of the software on your system with a specific E-mail adddress. FILExt has no plans to do this and the attachments will be stripped from the mail and the mail itself deleted as soon as it arrives. Your privacy is important to FILExt and what you have on your specific system is of no interest; how your system associates file types with extensions and programs is what's important and that will be the only data collected. This data will be amassed with other submissions and any individual contributions will not be able to be pulled out of the amassed data as any association with a specific E-mail address is never recorded anywhere. You can see the results of this collection at the bottom of most FILExt results pages.

How to Read the Submission

If interested, you can view the submission in any text editor. The submission is basically a collection of two different Windows commands: "assoc" and "ftype".

The "assoc" command outputs a list of each file extension recorded in the registry followed by the file type associated with that extension. The file type is basically a short name for whatever program is to be run when a file with that particular extension is clicked on in Windows. The output list is alphabetical and is the first half of the submission file.

The Echo command above then adds a divider to the file just to tell FILExt where the "assoc" command output ends and the "ftype" output begins.

The "ftype" command then outputs a list of each file type (short name) and the specific command to run when that file type is activated (by clicking on the associated file extension). This data tells FILExt what program has captured a particular file type and file extension in your system. In most cases, vendors use descriptive folder and file names for their software so in those cases the specific program and folder it is in gives a clear hint which program has captured the file extension. Other users can use this information in their search for programs they might need to open a file with the same file extension.

A typical combined entry might look like this...

ASR.....asrfile....."C:\Program Files\Macromedia\Dreamweaver MX 2004\Dreamweaver.exe" "%1"

...and that same information will appear in the FILExt database and be displayed under the appropriate file extension (in the case above, ASR).

While it looks odd, there is a significant amount of data in that line. It basically tells you that on some systems the .ASR file extension will be called an "asrfile" and will be associated with the program Dreamweaver MX 2004 made by the company Macromedia. Fortunately, many companies put executable files into a path that often gives you both the name of the program and the name of the company. Even if that data is not present in the pathname you can often get additional information by running a Google search on the .EXE file name itself.

Some entries will have following data such as the "%1" above. These are parameters fed to the program (e.g., often %1 will mean the name of the file clicked on) and these entries can be ignored for the most part.

Some entries will have variables as part of the path to the .EXE file. The two most common are:

  • %SystemRoot% which symbolically represents the path to your Windows folder, and
  • %ProgramFiles% which symbolically represents the path to your Program File folder.

Some entries will show a shortened version of a folder name. For example, C:\PROGRA~1\ is a short name for the C:\Program Files\ folder. Back in the old days of MS-DOS files and folders were limited to names no longer than eight characters before the period and three characters after (summarized as 8.3 format). Windows maintains compatibility with that restriction and any file/folder names longer than 8.3 format are shortened. There are rules for this shortening process but basically, the rootname of the file is shortened to six characters and then ~1 is added to that for the first instance of that six characters. If there is a duplicate six character name then you'd see ~2 added and ~3 if there are two duplicates.

Some entries will not reference a specific file name but, instead a CLSID of the form {f39a0dc0-9cc8-11d0-a599-00c04fd64433} is seen. The CLSID is an ActiveX class identifier and each ActiveX class, whether it is a compound document object, an ActiveX control or some other class of ActiveX module, is assigned a unique CLSID.The unique string used for each CLSID is called a globally unique identifier, or GUID, and programmers use a utility called Guidgen.exe to generate the number. CLSIDs are stored as 16-byte values and appear as long strings of numbers enclosed in braces. Each CLSID takes the form of 8, 4, 4, 4 and 12 hex digits separated by hyphens. The CLSID is yet another shorthand name for something that Windows uses and it is unique to whatever it references. To find a specific association between a CLSID and a program or process you need to look in the registry. One site that attempts to list CLSIDs and what they refer to is

Finally, some entries will point to seemingly the same program, perhaps multiple times. Since an exact match routine is used when analyzing submissions any differences will result in a separate entry. These can be caused by different language versions of Windows (e.g., English versions use C:\Program Files\ while Italian versions use C:\Programmi\), different versions of a program, or other minor differences. These are being left in the database as they can point to the various versions of a program that uses a file extension and give some indication of how long that program has been using that extension (e.g., older versions of Paint Shop Pro used .PSP and while newer versions still read that file, they write .PSPImage files by default instead).


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