NAME

file − determine the type of a file by examining its contents

SYNOPSIS

file [ −c ] [ −f ffile ] [ −m ] filename ... 

DESCRIPTION

file command performs a series of tests on each filename in an attempt to classify the type.  If the contents of the file appear to be ASCII text, file command examines the first 1024 bytes to determine what languages are used.  If the file is an executable file, a.out, file command displays CPU type, 68k or mips.  If the file is a symbolic link, file command displays the name and the type of the file that are referenced by the link as follows,

symbolic link to filname of type

Each file, usually at the beginning, has a magic number, a numeric or string constant, to indicate its file type.  file command uses the file /etc/magic to classify type of each file according to its magic number. 

OPTIONS

−c Check the format errors in the magic number file.  For the reasons of efficiency, this validation is not normally carried out. No file type-checking is done under −c option. 

−f ffile Classify the types of files specified in ffile. 

−m mfile Use mfile as an alternate magic number file. 

MULTIPLE LANGUAGE SUPPORT

If the file is one of JIS, Shift-JIS, EUC, TCA(The Republic of China), or Mail code, file command classify the code type.  JIS code and Mail code are identified using the following escape sequences:

ESC $ @JIS C 6226-1978 Kanji character-set
ESC $ BJIS X 0208-1983 Kanji character-set
ESC ( BASCII (ANSI X3.4-1986)
ESC ( JJIS X 0201-1976 JIS Roman character-set
ESC ( IJIS X 0201-1976 JIS Katakana character-set
ESC ( HSwedish character-set (often JIS Roman character set)
ESC $ ( CKorean character-set (KS C 5601-1987)
ESC $ ( 0, ESC $ ( 1, ESC $ ( ?
The Repubic of China  character-set (CNS 11643-1986)

IDENTIFY FILE TYPE

• File status report
  symbolic link to [file name]
  character special (Major/Minor)
  block special (Major/Minor)
  directory
  fifo
  socket
 • File contents (magic number file independent)
  empty
  executable script for /bin/csh
  executable script for /bin/sh
  c-shell commands
  shell commands
  sccs
  RCS file
  PRESS file
  data
  c program text
  fortran program text
  assembler program text
  [nt]roff, tbl, or eqn input text
  troff (CAT) output
  commands text
  troff intermediate output text
  english text
  ascii text
 • File contents (magic number file dependent)
  cpio archive
  ASCII cpio archive
  very old archive
  apl workspace
  packed data
  System V Rel.1 ar archive
  current ar archive
  pdp11/pre System V vax executable
  unix-rt ldp
  pdp11 overlay
  pdp11/pre System V vax pure executable
  demand-page executable
  pdp11 separate I&D
  pdp11 kernel overlay
  vax executable
  vax pure executable
  basic-16 executable
  basic-16 executable (TV)
  x86 executable
  x86 executable (TV)
  3b20 executable
  3b20 executable (TV)
  3b2/3b5 executable
  3b2/3b5 executable (TV)
  MC68k executable
  MC68k executable (shared)
  MC68k executable (shared demand paged)
  68k executable
  68k pure executable
  68k demand paged pure executable
  PostScript document
  Frame Maker document
  Frame Maker MIF file
  Frame Maker MML file
  MIPS endian big executable
  MIPS endian big pure
  MIPS endian big demand paged
  MIPS endian little executable
  MIPS endian little pure
  MIPS endian little demand paged
  swapped MIPS-eb executable
  swapped MIPS-eb pure
  swapped MIPS-eb demand paged
  swapped MIPS-el executable
  swapped MIPS-el pure
  swapped MIPS-el demand paged
  MIPS endian big ucode
  MIPS endian little ucode
  MS-DOS library
  Microsoft x.out
  old Microsoft 8086 x.out
  BSD archive random library
  MIPS archive
  archive
  compressed data
  SONY multi media format
  CDFF file

FILES

/etc/magicmagic number file

SEE ALSO

ld(1), magic(5)

BUGS

It often makes mistakes.  In particular, it often suggests that command files are C programs. 

Does not recognize Pascal or LISP. 

NEWS-OSRelease 4.2.1R