FILE(1) FILE(1)
NAME
file - determine file type
SYNOPSIS
file [ -m ] [ file ... ]
DESCRIPTION
File performs a series of tests on its argument files in an
attempt to classify their contents by language or purpose.
If no arguments are given, the classification is performed
on standard input.
If the -m flag is given, file outputs an appropriate MIME
Content-Type specification describing the type and subtype
of each file.
The file types it looks for include directory, device file,
zero-filled file, empty file, Plan 9 executable, PAC audio
file, cpio archive, tex dvi file, archive symbol table,
archive, rc script, sh script, PostScript, 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.
If a file has no apparent format, file looks at the charac-
ter set it uses to classify it according to ASCII, extended
ASCII, Latin ASCII, or UTF holding one or more of the fol-
lowing blocks of the Unicode Standard: Extended Latin,
Greek, Cyrillic, Armenian, Hebrew, Arabic, Devanagari, Ben-
gali, Gurmukhi, Gujarati, Oriya, Tamil, Telugu, Kannada,
Malayalam, Thai, Lao, Tibetan, Georgian, Japanese, Chinese,
or Korean.
If all else fails, file decides its input is binary.
SOURCE
/sys/src/cmd/file.c
BUGS
It can make mistakes.
Page 1 Plan 9 (printed 10/30/25)