.\" SCCSID: @(#)file.1  3.1   1/13/8.TH file 1.SH Namefile \- determine file type.SH Syntax.B file[.B \-c] [.B \-fffile] [.B \-mmfile]\fIfilename\fR ....SH Description.NXR "file command (general)".NXR "file" "determining extension"The.PN filecommand performs a series of tests on each .I filenameargumentin an attempt to classify it.If an argument appears to be ASCII, the.PN filecommandexamines the first 1024 bytesand tries to guess its language..PPFor character special files, part of this classification is informationabout which devices the system shows as active.In particular, device-specific information such as controller typeand unit, device type and unit, and status (offline, write locked,density, errors)is returned. The general categories currently implemented are disk, tape,and terminal devices. The supported terminal devices includeLocal Area Terminals (LAT)but not Local Area Network (LAN) pseudo-terminals..PPThe.PN filecommanduses the file.PN /usr/lib/file/magicto identify files that have some sort of.I magic.IR number .A.I magic numberis any numeric or string constant that identifies the filecontaining the constant.Commentary at the beginning of.PN /usr/lib/file/magicexplains its format..SH Options.IP \-c 5Checks the magic file for format errors by printing the internalrepresentation of the magic file.No file typing is done under.B \-c..IP \-fInterprets the following argument to be a file containing thenames of the files to be examined..IP \-mInstructs.I fileto use an alternate magic file..SH RestrictionsIt often does a poor job of distinguishingC programs, shell scripts, English text, and ASCII text..PPIt does not recognize many programming languages, including Modula,Pascal, and Lisp..SH Files/usr/lib/file/magic.SH See Alsomagic(5)