How To Analyze Real File Types With Directory List & Print Pro


How To Verify File Types By File Signature

Directory List & Print is a well known software tool to list, print and export individually desired file and folder listings. In addition to numerous valuable features, Directory List & Print Pro enables to verify the real file type by file signature for all files in a directory at once. Learn in the video below how quickly and easily this can be done:

Below you will learn more about file formats, file extensions and file signatures.


File Formats And File Extensions

There are countless file formats. The fastest way to determine a file format / file type is by its file extension; e.g. .doc, .docx, .xls, .jpg, .gif, .png, .mp3, .mp4, just to name a few of the most common file extensions and corresponding formats. There are thousands of different file formats of documents, images, videos, audio files etc. The Windows operating system requires the correct file extension in order to open a file with the appropriate application. On the website  thousands of file extensions are listed including additional information about file type, file format, usage and with what applications the file can be opened.

For more information about file extensions / formats and how to convert the files from one format to another read the helpful post by Tim Fisher on abouttech


How Can A File Extension Be Wrong?

It may happen that a file extension is incorrect, what means it does not match the real file format. The file extension might have been mistakenly overwritten or changed intentionally. A file extension can be modified intentionally in order to hide the true file type. For example a video, image or a .rar-file should be hidden, also beacause the .rar file is a common file type for spreading software cracks. However, file extensions may also be changed in order to spread viruses and trojans more easily.

By the way, in computer forensics determining the file type is part of the remit. The computer forensic investigator has to check whether there are incorrect file extensions in a given dataset and thus disguised data.


Determine True File Type

In many files the correct file type is contained in the file signature in the file header. In order to verify the file signature a file has to be opened via text-editor or a hex-editor (hexadecimal).

This is what you will see in a hex-editor  (PNG image header example):

Check file types by file signature







In order to open a file in Windows the correct file extension must be known. The correct file extension can be verified by the file signature in the file header of many files. Directory List & Print Pro includes a helpful feature in order to verify quickly and easily the file extensions of files of complete folders.    



Do you have any questions about Directory List & Print and how to verify file types? Do you have any suggestions for future updates of the software? We look forward to your feedback at