ref: e72da62915b09d5673b0c0179ba8dfe045aeb8c3
dir: /sys/man/1/file/
.TH FILE 1 .SH NAME file \- determine file type .SH SYNOPSIS .B file [ .B -m ] [ .I file \&... ] .SH DESCRIPTION .I File performs a series of tests on its argument .I files in an attempt to classify their contents by language or purpose. If no arguments are given, the classification is performed on standard input. .PP If the .B -m flag is given, .I file outputs an appropriate MIME .B Content-Type specification describing the .B type and .B subtype of each file. .PP The file types it looks for include directory, device file, zero-filled file, empty file, Plan 9 executable, PAC audio file, .B cpio archive, .B tex .B dvi file, archive symbol table, archive, .B rc script, .B sh script, PostScript, .B troff output file for various devices, mail box, GIF, FAX, object code, C and Alef source, assembler source, compressed files, encrypted file, English text, compressed image, image, subfont, and font. .PP If a file has no apparent format, .I file looks at the character set it uses to classify it according to .SM ASCII\c , extended .SM ASCII\c , Latin .SM ASCII\c , or .SM UTF holding one or more of the following blocks of the Unicode Standard: Extended Latin, Greek, Cyrillic, Armenian, Hebrew, Arabic, Devanagari, Bengali, Gurmukhi, Gujarati, Oriya, Tamil, Telugu, Kannada, Malayalam, Thai, Lao, Tibetan, Georgian, Japanese, Chinese, or Korean. .PP If all else fails, .I file decides its input is binary. .SH SOURCE .B /sys/src/cmd/file.c .SH BUGS It can make mistakes.