A file extension is a 2-3 character abbreviation of letters and numbers appended to the file name. It is mainly used to identify a file: so that the OS knows which program to open a given file type.
For example, one of the most popular music formats is 'mp3'. By default, in the OS Windows such files are opened by the program Windows Me dia Player. If the extension ('mp3') of such a file is changed to 'jpg' (picture format), then this music file will try to open a completely different program in the OS and will most likely show you an error that the file is corrupted. Therefore, the file extension is very important thing.
In OS Windows 7, 8, usually, file extensions are not displayed. Instead, the user is prompted to identify file types by icons. In principle, you can use the icons only when you need to change the file extension – you must first enable its display. Let's consider a similar question further …
How to enable extension display
1) We go into the explorer, on the top of the panel, click on 'arrange / folder options …'. See screenshot below.
Figure: 1 Folder options in Windows 7
2) Next, go to the 'view' menu and turn the mouse wheel to the end.
Figure: 2 menu view
3) At the very bottom, we are interested in two points:
'Hide extensions for registered file types' – uncheck this item. After that, you will begin to display all file extensions in Windows 7.
'Show hidden files and folders' – it is also recommended to enable it, only be careful with the system drive: before removing hidden files from it – 'measure seven times' …
Figure: 3 Show file extensions.
Actually, the setup in Windows 7 is complete.
1) We go into the explorer in any of the folders. As you can see in the example below, there is a text file, but the extension is not displayed.
Figure: 4 Display file in Windows 8
2) Go to the 'view' menu, the panel is on top.
Figure: 5 Menu view
3) Next, in the 'view' menu, you need to find the 'File name extensions' function. You need to check the box next to it. Usually this area is on the left, top.
Figure: 6 Check the box to enable the display of the extension
4) Now the extension display is on, it is 'txt'.
Figure: 6 Editing the extension …
How to change the file extension
1) In the explorer
It is very easy to change the extension. It is enough to right-click on the file and select the Rename command from the pop-up context menu. Then after the dot, at the end of the file name, replace 2-3 characters with any others (see Fig. 6 just above in the article).
2) In commanders
In my opinion, for these purposes it is much more convenient to use some kind of file manager (many call them commanders). I love using Total Commander .
Official website: http://wincmd.ru/
One of the best software of its kind. The main direction is to replace the explorer for working with files. Allows you to perform a wide range of different tasks: file search, editing, group renaming, working with archives, etc. I recommend having a similar program on your PC.
So, in Total'e you see both the file and its extension at once (i.e., you don't need to include anything in advance). By the way, it's pretty easy to turn on all hidden files immediately (see Figure 7 below: red arrow).
Figure: 7 Editing the file name in Total Commander.
By the way, unlike Explorer, Total does not slow down when viewing a large number of files in a folder. For example, open a folder with 1000 pictures in Explorer: even on a modern and powerful PC, you will notice slowdowns.
Do not forget that an incorrectly specified extension can affect the opening of a file: the program may simply refuse to launch it!
And one more thing: do not change extensions unnecessarily.