File extension tells you more about the file type. Example a .pdf indicates that the file is a 'Print Document Format' file which can be opend using Adobe Acrobat or Adobe Reader. Look at the sites below for a list of file extensions:
http://www.extensionpedia.com/html/list.html
basically a file extension is that tells the computer what program to open it and what process the program should take for an immediate command
The file extension tells about the type of file, with the extension three letters. For Eg:- *.txt -- text file *.exe-- executable file
minimum three and maximum four
The extension. It tells Windows what kind of a file it is. For example, a file with the ".doc" extension is a Microsoft Word Document.
its an extension for the file name which tells about the file type. but I just have a query, why most of the extensions are three lettered
File extensions tell the computer what kind of program was used to create it, and are usually three letters. Common file extensions are .txt .doc .wps
An old convention stemming from MS-DOS ca. 1983, which only allowed 8+3 characters in file names - 8 in the name and 3 for the extension. Since MS-DOS used the file extension to look up which program could open it, and there were many programs, developers would commonly use all three characters in their extensions.Neither Unix/Linux nor Mac had these requirements, but the convention is still with us.
XLS is the shorthand for Microsoft Excel file extension. A file extension is the group of letters following a period in a file name, denoting what kind of file it is.
Extension
The file extension. It comes after the file nice, after the last dot in the name. For example someTextDocumet.txt has the extension TXT for plain text. The program that created it is most likely the default one for opening it.
A text file, usually with numbers, letters, and/or simple graphics.
A Microsoft Word file has a .doc extension.
What is the file extension What is the file extension