term% cat index.txt FILE(1) General Commands Manual FILE(1)
NAME
file - determine file type
SYNOPSIS
file [ 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.
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, Post‐
Script, troff output file for various devices, GIF, FAX, picfile(9.6),
object code, C and Alef source, assembler source, compressed files, en‐
crypted file, English text, Plan 9 bitmap, Plan 9 subfont, Plan 9 font.
If a file has no apparent format, file looks at the character set it
uses to classify it according to ASCII, extended ASCII, Latin ASCII, or
UTF holding one or more of the following blocks of the Unicode Stan‐
dard: Extended Latin, Greek, Cyrillic, Armenian, Hebrew, Arabic, De‐
vanagari, Bengali, 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, for example classifying a file of decimal data,
etc. as troff(1) input.
FILE(1)