First, What is a file extension?
In computing, a file extension is a string attached to the name of a file, usually preceded by a point. Its main function is to differentiate the contents of the file so that the operating system has the necessary procedure to execute or interpret, however, the extension is only a part of the file name and does not represent any obligation on its content. Some, especially those derived of DOS and Windows operating systems use file extensions to recognize their format, including executable files. Other operating systems, such as Unix, use the file extensions by simple convention, not necessarily using them to determine its type. As extensions legacy DOS file system, many of its current characteristics were inherited by limitations in the system. The old DOS systems limited the number of characters of the file extension to three, so many conventional extensions own that amount of characters. In addition, the file names in DOS systems are case insensitive, so that most file extensions can be written indifferently in lowercase and uppercase or a combination of both.
So, what is the problem about extensions?
Often it happens, for unknown extension files (In emails, mostly), or in any way to delete or modify file extensions stored on the computer, which leads to the impossibility of open those files. If you are in a situation where you can not open certain files because format is unknown, a simple method with which you can identify what extension have these files (or what kind of files are).
In windows OS, a situation may arise if you originally reached such a file was worked on a Mac. In linux there is no problem because if you accidentally delete a file extension, the system will recognize itself and, in some cases, automatically restore.
This site aims to be a quick and accessible guide on how to resolve cases in which we meet with unknown extensions. We’ll talk from manual solutions to some applications under Windows, to identify files whose extension is not recognizable.