What are file extensions in Windows? - PC SEEKERS

What are file extensions in Windows?


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Having the right tool to do a job is important but how do you know exactly what the right tool is? For example you will never know how the chefs make a dish like a pudding in some exact shape unless you have not seen the moulds that they use. But your computer knows exactly which program to use to open certain files say a photo or a video or a document basically every time. That's thanks to the 'File extension'.


Also Read: Fixing Common Windows Errors


File extensions are those 2,3 or 4 letters that you see after the file name when you're poking around in your storage (hard drive or SSD). .doc, .mp3 and .exe for example are all file extensions. Your Operating System (OS) doesn't just analyze the internal code of a file and figure out what kind of a file it is, that would be an inefficient process. Instead, which ever program created that file will slap an extension on to the end to tell the OS exactly what kind of data is inside.


For example, if you ever save a document in word you have probably seen that drop down menu that lets you pick exactly what format you want the file to be saved in. After you make your choice, word will attach the appropriate extension so that Windows will know to use Word if you saved it as a standard Word document (.docx),  Notepad if its plain text (.txt) or Adobe Reader if it's a PDF (.pdf).

When you open a file, Windows (or any OS) will check the extension against a list of file type associations. You can change the default applications that open a particular file with a particular file extension, easily enough, by going to Settings --> Apps --> Default Apps --> Choose Default applications by file type. Here you can see and modify which program is assigned to which extension.


Now Windows will have a lot of default file type associations preloaded when the OS is first installed. For example, it will automatically know to use the built in photo viewer app to load up a .JPEG instead of trying to open it in a music player or an Email app or something.


But when you install new programs they will usually ask if they should be the default program for opening certain file extensions especially with popular media applications like VLC which will present you with a long list of extensions that you can pick and choose from.

And extensions are not just useful for getting your files to load up quickly, they also help you, the user, see exactly what they are at a glance in the file explorer as Windows will assign little icons to your files solely based on what the extension is.

There are also times when it's useful to change a file extension. Especially if you have downloaded a file from the internet that you really want to get into. It's possible that the creator of the file stuck the wrong extension on it or the file just doesn't have an extension at all. So slapping a .txt extension for example at the end of mysterious file can at least get note pad to open it, letting you have a peak inside. (Though we do not recommend opening mysterious files, specially ones that are downloaded from the internet.)

To see or change an extension just enable 'File name extensions' option in 'View' tab of the File Explorer in Windows 10. Checking this box will cause file extensions to appear everywhere, not a bad idea if you have downloaded a file that you are not sure about.

In fact, file extension trickery has led to some bad malware epidemics notably the love letter virus of the early 2000s. The bad guys sent out an email with an attachment that appeared to have a .txt extension fooling the user into thinking it was just a harmless plain text file which originally was a .vbs file in other words a script that contained malicious code. So be sure to pay attention to file extensions whenever you download anything and be especially wary if it's an unidentified .exe of .vbs as they have code that will run when you open them so be sure you know where they are coming from. So file extensions are important after all, they can warn us about the dodgy files and help our PCs run more faster.

Also Read: Are The Websites You Visit Tracking You?


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