Question

There is a virus that my brother got in his computer and what that virus did was to rename almost all files in his computer. It changed the file extensions as well. so a file that might have been named picture.jpg was renamed to kjfks.doc for example.

so what I have done in order to solve this problem is:

remove all file extensions from files. (I use a recursive method to search for all files in a directory and as I go through the files I remove the extension)

now the files do not have an extension. the files now look like:

I think this file names are stored in a local database created by the virus and if I purchase the anti virus they will be renamed back to their original name.

since my brother created a backup I selected the files that had a creation date latter than when my brother performed the backup. so I have placed that files in a directory.

I am not interested in getting the right extension as long as I can see the content of the file. for example, I will scan each file and if it has text inside I know it will have a .txt extension. maybe it was a .html or .css extension I will not be able to know that I know.

I belive that all pdf files should have something in common. or doc files should also have something in common. How can I figure what the most common types (pdf, doc, docx, png, jpg, etc) files have in common)

Edit:

I know it will probably take less time to go over all this 200 files and test each one instead of creating this program. it is just that I am curios to see if it will be possible to get the file extension.

Answer 1

In unix, you can use file to determine the type of file. There is also a port for windows and you can obviously write a script (batch, powershell, etc.) or C# program to automate this.