file is a program originated in Unix that runs under the shell (command-line) to determine the file type heuristically instead of other simpler ways to classify it, like with file extensions, MIMEs, etc. It also extracts the magic number from executable files. Jump to: navigation, search It has been suggested that List of Unixes be merged into this article or section. ... Jump to: navigation, search It has been suggested that this article or section be merged into Shell_(computing). ... A command line interface or CLI is a method of interacting with a computer by giving it lines of textual commands (that is, a sequence of characters) either from keyboard input or from a script. ... Multipurpose Internet Mail Extensions (MIME) is an Internet Standard for the format of e-mail. ... Jump to: navigation, search In computer programming, a magic number is a special constant used for some specific purpose. ...

History

The original version originated from the Unix Research Version 4 as far as 1973. Then in System V was a major update with important changes (making it more flexible but slower) written by Ian Darwin from scratch. Geoff Collyer added more features and more accuracy in 1989. Other people has added functionality, like Guy Harris, Chris Lowth, Eric Fischer, and many others. The SunOS 3.2 and the current version are similar and compatible with the SVR4 because it is an improved version of the Sun program. It is currently mantained by Christos Zoulas. It is licensed under BSDAdClause and some parts are in the public domain. Jump to: navigation, search 1973 was a common year starting on Monday. ... In science, engineering, industry and statistics, accuracy is the degree of conformity of a measured or calculated quantity to its actual, nominal, or some other reference, value. ... Jump to: navigation, search 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... SunOS was the version of Unix used by Sun Microsystems for their workstations that debuted in 1982. ... The many divergents of System V System V, previously known as AT&T System V, was one of the versions of the Unix computer operating system. ... BSD redirects here; for other uses see BSD (disambiguation). ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...

Linux output examples

 file.c: C program text file: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), stripped /dev/wd0a: block special (0/0) /dev/hda: block special (3/0) /dev/wd0b: data /dev/wd0d: x86 boot sector /dev/hda: x86 boot sector /dev/hda1: Linux/i386 ext2 filesystem /dev/hda2: x86 boot sector /dev/hda3: x86 boot sector, extended partition table /dev/hda4: Linux/i386 ext2 filesystem /dev/hda5: Linux/i386 swap file /dev/hda6: Linux/i386 swap file /dev/hda7: Linux/i386 swap file /dev/hda8: Linux/i386 swap file /dev/hda9: empty file.c: text/x-c file: application/x-executable, dynamically linked (uses shared libs),not stripped /dev/hda: application/x-not-regular-file /dev/wd0a: application/x-not-regular-file 

External links

• Official webpage
• [1] The program's manpage]