A file extension indicates what type of file it is. For instance .doc is a word document, .jpg is a picture. Google file extensions and you should be able to get a list of all the file extensions and what they mean.
A file extension is used to identify to the computer and to the user what the type of file is. For example, if one sees a file such as MyProg.pas, this can be identified as a Pascal source code file. On the other hand, if the file is named XMas2014.jpg, then this is a JPEG picture. The extension is a way for the computer to know how to open the file when it is double-clicked. So, when you double-click the aforementioned JPEG picture, it will open in whatever program is set to be the default for that type of file (Windows Fax and Picture Viewer, for example).
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The file extension for PHP is .php
An .fsg file is the extension used by IBM Voice Type. An old file extension, not supported yet.
The .opt file extension is used by innumerable programs. it is usually an option / configuration file, but is also used for certain document types.
What is the file extension What is the file extension
A .ppt file is a file to be used in the Microsoft PowerPoint software.
A batch file, often used by computer processes to perform a series of stored operations as a group, have the file extension .bat.
.ppt is the file extension for power point files
.dbs
It is used by Labview from National Instruments.
file extension for video is 101
.docx The extension docx is used in Word 2007.
.pfx