Fundamentals of Informatics. What is a file extension?

Each file on the computer stores data of a certain type. For example, it can be text information, program codes, image, sound or something else. Intuitively, you already understand what a file extension is. Therefore, today we will fill the gaps in knowledge and try to delve deeper into the topic.

Definition

The extension is the second part of the file name, located after the point. Typically, it consists of 2-4 characters. This designation simplifies the operation of the operating system, prompting it what kind of information is contained in the document and what program should be used to open the file.

When you install any new program in the Windows registry, you enter information about what formats it can work with. It is thanks to this that pictures are opened in special galleries, and music - with the help of a multimedia player. If you want, you can change the program that will be used to open files of a certain type.

Popular extensions

It is useful to know not only what the file extension is, but also what types of data are stored in different documents. Here is the list of the most common in Windows:

• Text: txt, .doc (.docx), .rtf.
• Web pages: .htm and .html.
• Archives: .zip, .rar.
• Images: .jpg (.jpeg), .png, .bmp, .gif, .tiff.
• Audio: .mp3, .wav, .wma, .cda.
• Video: .avi, .wmv, .mpg (.mpeg), .MPEG-4, .wmv, .flv, .vob, .mdv, .swf.
• Presentations: .ppt (.pptx).
• Tables: .xls (.xslx).
• Fonts: .ttf, .otf.
• Electronic books: .pdf, .epub, .fb2, .djvu.
• Databases: .mdb, .accdb.
• Executables (running or installing programs): .exe, .bat.

Tip: when working with documents of unknown formats, the Russian-language service Open-File.ru is very helpful. Just enter the name in the search for the directory, and you will see the basic information: what data contains the document (image, text, etc.), what suitable program for expanding the file in which it can be opened.

Configuring display extensions

By default, the operating system automatically displays the document format near its name. However, at any time you can make sure that the file extensions in Windows are not displayed or, conversely, include them. What do I need to do?

1. Go to the "Control Panel".
2. Find the "Folder Options" item . In Windows 7, it is called "Folder Options", and in Windows 8 and 10 - "Explorer Settings".
3. In the window that appears, select the "View" tab.
4. Find the item "Hide extensions for registered file types" in the "Additional Options" list and tick the box next to it.
5. Click "Apply" and close the window.

Note: if the file extension in Windows 7 or another OS version is disabled, you need to be more careful when renaming any documents. If you unintentionally delete or change this postscript, the file can not be opened.

How to change the extension

Now that you know what a file extension is, let's talk about how to convert it. This is necessary if, for example, you want to open a file for one program in another application.

Strictly speaking, there are two ways to do this:

1. Rename the document - just write instead of the "native" extension that you need (for example, .html instead of .txt).
2. Use special converter programs. Some are installed on a PC, others are available online. They are used in case if you want to completely change the encoding of the document.

If you want the information displayed in the other program to be as accurate as possible, it's better to use full-featured converters.

Of popular services of this type is Convertio. This online converter supports most common file extensions, and also has a number of additional tools, such as compressing and merging PDF documents, a URL converter for extracting music and video from sites, and recognizing scanned text.

How to change the program for opening

And, finally, consider the situation when you downloaded a new application and want to use it to work with certain documents. For example, change the standard program for viewing photos in Windows on Microsoft Office Picture Manager. How to do it?

1. Select the desired file and open the context menu (right mouse button).
2. Find the item "Open with"> "Select another application".
3. Select the program in the list that appears and check the box next to "Always use this application ...".
4. Click "OK."

This means that such a file extension will now be opened by the program that you selected. In Windows 8 and 10, if a suitable application is not found on the PC, you also have the option to find it in the "Store".