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The Curious Bag
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The file extension for a computer file indicates the type of file. For example, a text file will have the file extension "txt." It is added as a suffix after the name of the file and separated from the file by a dot (".").
Length
The length of a file extension can be anywhere from one to five characters.
Use
The file extension is used by the operating system to determine the program that should be used to open the file. It also allows users to see the file type without opening it.
Omission
Unix and Linux operating systems will allow you to omit the file extension when naming a file. Windows operating systems will add a file extension for you.
Changing Extensions
You can change the file extension on any file, but doing so may cause problems with opening the file. The operating system will try to use the wrong software to open the file.
Common Types
Some common file extensions are "txt" (text), "doc" (Microsoft Word Document), "zip" (Zip archive file), "html" (hypertext markup file or Web page), and "jpeg" or "jpg" (image file).
Source:
Resource:
File Info: File Extensions Resource
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