File

PDF file example1. A file is an object on a computer that stores data, information, settings, or commands that are used with a computer program. In a graphical user interface (GUI) such as Microsoft Windows, files are shown as unique icons that relate to the program that opens the file. For example, the picture is an example of the icon associated with Adobe Acrobat PDF files. Double-clicking this icon in Windows would open that file in Adobe Acrobat or the PDF reader installed on the computer.

File list in explorer with name and file extension

File management

  • See our file system definition for further information about file management.

On a Windows computer the user can manage and organize their files by using Windows Explorer.

File extensions

There are millions of files used with computers today and are identified either by the file extension of the file or the data contained in the file. For example, as seen in the above example the first file shown in Explorer is "regedit.exe", "regedit" is the name of the file, and ".exe" is the file extension that identifies this file as an executable file. The next file "RtlExUpd.dll", which is a DLL file and another example of a file.

Illegal file characters

Notice: With most operating systems, the below characters are considered illegal and cannot be used. Trying to create a file with these characters in the filename would generate an error or make the file inaccessible.

\ / : * ? " < > |

In addition to the above invalid characters many operating systems including Windows has reserved words that can also not be included in a file name. See the reserved word definition for examples of reserved words.

Related pages

2. Linux command, see the file command page for additional information about this command.

Also see: Batch file, Binary file, Closed file, Data file, Directory, Executable file, File extension, File viewer, Hidden files, Hierarchical file system, Interchangeable file, Leaf, Long file names, Native file format, Open file, Operating system terms, Orphan file, PIF, Program, README file, Record, Software terms, Swap file, System file, Text file