Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
FILE(1)			FreeBSD	General	Commands Manual		       FILE(1)

NAME
     file -- determine file type

SYNOPSIS
     file [-bchiklLNnprsvz0] [--apple] [--mime-encoding] [--mime-type]
	  [-e testname]	[-F separator] [-f namefile] [-m magicfiles] file ...
     file -C [-m magicfiles]
     file [--help]

DESCRIPTION
     This manual page documents	version	"5.11" of the file command.

     file tests	each argument in an attempt to classify	it.  There are three
     sets of tests, performed in this order: filesystem	tests, magic tests,
     and language tests.  The first test that succeeds causes the file type to
     be	printed.

     The type printed will usually contain one of the words text (the file
     contains only printing characters and a few common	control	characters and
     is	probably safe to read on an ASCII terminal), executable	(the file con-
     tains the result of compiling a program in	a form understandable to some
     UNIX kernel or another), or data meaning anything else (data is usually
     ``binary''	or non-printable).  Exceptions are well-known file formats
     (core files, tar archives)	that are known to contain binary data.	When
     modifying magic files or the program itself, make sure to preserve	these
     keywords.	Users depend on	knowing	that all the readable files in a
     directory have the	word ``text'' printed.	Don't do as Berkeley did and
     change ``shell commands text'' to ``shell script''.

     The filesystem tests are based on examining the return from a stat(2)
     system call.  The program checks to see if	the file is empty, or if it's
     some sort of special file.	 Any known file	types appropriate to the sys-
     tem you are running on (sockets, symbolic links, or named pipes (FIFOs)
     on	those systems that implement them) are intuited	if they	are defined in
     the system	header file <sys/stat.h>.

     The magic tests are used to check for files with data in particular fixed
     formats.  The canonical example of	this is	a binary executable (compiled
     program) a.out file, whose	format is defined in <elf.h>, <a.out.h>	and
     possibly <exec.h> in the standard include directory.  These files have a
     ``magic number'' stored in	a particular place near	the beginning of the
     file that tells the UNIX operating	system that the	file is	a binary exe-
     cutable, and which	of several types thereof.  The concept of a ``magic''
     has been applied by extension to data files.  Any file with some invari-
     ant identifier at a small fixed offset into the file can usually be
     described in this way.  The information identifying these files is	read
     from the compiled magic file /usr/share/misc/magic.mgc, or	the files in
     the directory /usr/share/misc/magic if the	compiled file does not exist.
     In	addition, if $HOME/.magic.mgc or $HOME/.magic exists, it will be used
     in	preference to the system magic files.

     If	a file does not	match any of the entries in the	magic file, it is
     examined to see if	it seems to be a text file.  ASCII, ISO-8859-x,	non-
     ISO 8-bit extended-ASCII character	sets (such as those used on Macintosh
     and IBM PC	systems), UTF-8-encoded	Unicode, UTF-16-encoded	Unicode, and
     EBCDIC character sets can be distinguished	by the different ranges	and
     sequences of bytes	that constitute	printable text in each set.  If	a file
     passes any	of these tests,	its character set is reported.	ASCII,
     ISO-8859-x, UTF-8,	and extended-ASCII files are identified	as ``text''
     because they will be mostly readable on nearly any	terminal; UTF-16 and
     EBCDIC are	only ``character data''	because, while they contain text, it
     is	text that will require translation before it can be read.  In addi-
     tion, file	will attempt to	determine other	characteristics	of text-type
     files.  If	the lines of a file are	terminated by CR, CRLF,	or NEL,
     instead of	the Unix-standard LF, this will	be reported.  Files that con-
     tain embedded escape sequences or overstriking will also be identified.

     Once file has determined the character set	used in	a text-type file, it
     will attempt to determine in what language	the file is written.  The lan-
     guage tests look for particular strings (cf.  <names.h>) that can appear
     anywhere in the first few blocks of a file.  For example, the keyword .br
     indicates that the	file is	most likely a troff(1) input file, just	as the
     keyword struct indicates a	C program.  These tests	are less reliable than
     the previous two groups, so they are performed last.  The language	test
     routines also test	for some miscellany (such as tar(1) archives).

     Any file that cannot be identified	as having been written in any of the
     character sets listed above is simply said	to be ``data''.

OPTIONS
     -b, --brief
	     Do	not prepend filenames to output	lines (brief mode).

     -C, --compile
	     Write a magic.mgc output file that	contains a pre-parsed version
	     of	the magic file or directory.

     -c, --checking-printout
	     Cause a checking printout of the parsed form of the magic file.
	     This is usually used in conjunction with the -m flag to debug a
	     new magic file before installing it.

     -e, --exclude testname
	     Exclude the test named in testname	from the list of tests made to
	     determine the file	type.  Valid test names	are:

	     apptype   EMX application type (only on EMX).

	     ascii     Various types of	text files (this test will try to
		       guess the text encoding,	irrespective of	the setting of
		       the `encoding' option).

	     encoding  Different text encodings	for soft magic tests.

	     tokens    Ignored for backwards compatibility.

	     cdf       Prints details of Compound Document Files.

	     compress  Checks for, and looks inside, compressed	files.

	     elf       Prints ELF file details.

	     soft      Consults	magic files.

	     tar       Examines	tar files.

     -F, --separator separator
	     Use the specified string as the separator between the filename
	     and the file result returned.  Defaults to	`:'.

     -f, --files-from namefile
	     Read the names of the files to be examined	from namefile (one per
	     line) before the argument list.  Either namefile or at least one
	     filename argument must be present;	to test	the standard input,
	     use `-' as	a filename argument.  Please note that namefile	is
	     unwrapped and the enclosed	filenames are processed	when this
	     option is encountered and before any further options processing
	     is	done.  This allows one to process multiple lists of files with
	     different command line arguments on the same file invocation.
	     Thus if you want to set the delimiter, you	need to	do it before
	     you specify the list of files, like: ``-F @ -f namefile'',
	     instead of: ``-f namefile -F @''.

     -h, --no-dereference
	     option causes symlinks not	to be followed (on systems that	sup-
	     port symbolic links).  This is the	default	if the environment
	     variable POSIXLY_CORRECT is not defined.

     -i, --mime
	     Causes the	file command to	output mime type strings rather	than
	     the more traditional human	readable ones.	Thus it	may say
	     `text/plain; charset=us-ascii' rather than	``ASCII	text''.

     --mime-type, --mime-encoding
	     Like -i, but print	only the specified element(s).

     -k, --keep-going
	     Don't stop	at the first match, keep going.	 Subsequent matches
	     will be have the string `\012- ' prepended.  (If you want a new-
	     line, see the -r option.)

     -l, --list
	     Print information about the strength of each magic	pattern.

     -L, --dereference
	     option causes symlinks to be followed, as the like-named option
	     in	ls(1) (on systems that support symbolic	links).	 This is the
	     default if	the environment	variable POSIXLY_CORRECT is defined.

     -l	     Shows sorted patterns list	in the order which is used for the
	     matching.

     -m, --magic-file magicfiles
	     Specify an	alternate list of files	and directories	containing
	     magic.  This can be a single item,	or a colon-separated list.  If
	     a compiled	magic file is found alongside a	file or	directory, it
	     will be used instead.

     -N, --no-pad
	     Don't pad filenames so that they align in the output.

     -n, --no-buffer
	     Force stdout to be	flushed	after checking each file.  This	is
	     only useful if checking a list of files.  It is intended to be
	     used by programs that want	filetype output	from a pipe.

     -p, --preserve-date
	     On	systems	that support utime(3) or utimes(2), attempt to pre-
	     serve the access time of files analyzed, to pretend that file
	     never read	them.

     -r, --raw
	     Don't translate unprintable characters to \ooo.  Normally file
	     translates	unprintable characters to their	octal representation.

     -s, --special-files
	     Normally, file only attempts to read and determine	the type of
	     argument files which stat(2) reports are ordinary files.  This
	     prevents problems,	because	reading	special	files may have pecu-
	     liar consequences.	 Specifying the	-s option causes file to also
	     read argument files which are block or character special files.
	     This is useful for	determining the	filesystem types of the	data
	     in	raw disk partitions, which are block special files.  This
	     option also causes	file to	disregard the file size	as reported by
	     stat(2) since on some systems it reports a	zero size for raw disk
	     partitions.

     -v, --version
	     Print the version of the program and exit.

     -z, --uncompress
	     Try to look inside	compressed files.

     -0, --print0
	     Output a null character `\0' after	the end	of the filename.  Nice
	     to	cut(1) the output.  This does not affect the separator which
	     is	still printed.

     --help  Print a help message and exit.

FILES
     /usr/share/misc/magic.mgc	Default	compiled list of magic.
     /usr/share/misc/magic	Directory containing default magic files.

ENVIRONMENT
     The environment variable MAGIC can	be used	to set the default magic file
     name.  If that variable is	set, then file will not	attempt	to open
     $HOME/.magic.  file adds ``.mgc'' to the value of this variable as	appro-
     priate.  However, file has	to exist in order for file.mime	to be consid-
     ered.  The	environment variable POSIXLY_CORRECT controls (on systems that
     support symbolic links), whether file will	attempt	to follow symlinks or
     not.  If set, then	file follows symlink, otherwise	it does	not.  This is
     also controlled by	the -L and -h options.

SEE ALSO
     magic(5), hexdump(1), od(1), strings(1),

STANDARDS CONFORMANCE
     This program is believed to exceed	the System V Interface Definition of
     FILE(CMD),	as near	as one can determine from the vague language contained
     therein.  Its behavior is mostly compatible with the System V program of
     the same name.  This version knows	more magic, however, so	it will	pro-
     duce different (albeit more accurate) output in many cases.

     The one significant difference between this version and System V is that
     this version treats any white space as a delimiter, so that spaces	in
     pattern strings must be escaped.  For example,

	   >10	   string  language impress	   (imPRESS data)

     in	an existing magic file would have to be	changed	to

	   >10	   string  language\ impress	   (imPRESS data)

     In	addition, in this version, if a	pattern	string contains	a backslash,
     it	must be	escaped.  For example

	   0	   string	   \begindata	   Andrew Toolkit document

     in	an existing magic file would have to be	changed	to

	   0	   string	   \\begindata	   Andrew Toolkit document

     SunOS releases 3.2	and later from Sun Microsystems	include	a file command
     derived from the System V one, but	with some extensions.  This version
     differs from Sun's	only in	minor ways.  It	includes the extension of the
     `&' operator, used	as, for	example,

	   >16	   long&0x7fffffff >0		   not stripped

MAGIC DIRECTORY
     The magic file entries have been collected	from various sources, mainly
     USENET, and contributed by	various	authors.  Christos Zoulas (address
     below) will collect additional or corrected magic file entries.  A	con-
     solidation	of magic file entries will be distributed periodically.

     The order of entries in the magic file is significant.  Depending on what
     system you	are using, the order that they are put together	may be incor-
     rect.  If your old	file command uses a magic file,	keep the old magic
     file around for comparison	purposes (rename it to
     /usr/share/misc/magic.orig).

EXAMPLES
	   $ file file.c file /dev/{wd0a,hda}
	   file.c:   C program text
	   file:     ELF 32-bit	LSB executable,	Intel 80386, version 1 (SYSV),
		     dynamically linked	(uses shared libs), stripped
	   /dev/wd0a: block special (0/0)
	   /dev/hda: block special (3/0)

	   $ file -s /dev/wd0{b,d}
	   /dev/wd0b: data
	   /dev/wd0d: x86 boot sector

	   $ file -s /dev/hda{,1,2,3,4,5,6,7,8,9,10}
	   /dev/hda:   x86 boot	sector
	   /dev/hda1:  Linux/i386 ext2 filesystem
	   /dev/hda2:  x86 boot	sector
	   /dev/hda3:  x86 boot	sector,	extended partition table
	   /dev/hda4:  Linux/i386 ext2 filesystem
	   /dev/hda5:  Linux/i386 swap file
	   /dev/hda6:  Linux/i386 swap file
	   /dev/hda7:  Linux/i386 swap file
	   /dev/hda8:  Linux/i386 swap file
	   /dev/hda9:  empty
	   /dev/hda10: empty

	   $ file -i file.c file /dev/{wd0a,hda}
	   file.c:	text/x-c
	   file:	application/x-executable
	   /dev/hda:	application/x-not-regular-file
	   /dev/wd0a:	application/x-not-regular-file

HISTORY
     There has been a file command in every UNIX since at least	Research
     Version 4 (man page dated November, 1973).	 The System V version intro-
     duced one significant major change: the external list of magic types.
     This slowed the program down slightly but made it a lot more flexible.

     This program, based on the	System V version, was written by Ian Darwin
     <ian@darwinsys.com> without looking at anybody else's source code.

     John Gilmore revised the code extensively,	making it better than the
     first version.  Geoff Collyer found several inadequacies and provided
     some magic	file entries.  Contributions by	the `&'	operator by Rob	McMa-
     hon, <cudcv@warwick.ac.uk>, 1989.

     Guy Harris, <guy@netapp.com>, made	many changes from 1993 to the present.
     1989.

     Primary development and maintenance from 1990 to the present by Christos
     Zoulas <christos@astron.com>.

     Altered by	Chris Lowth <chris@lowth.com>, 2000: handle the	-i option to
     output mime type strings, using an	alternative magic file and internal
     logic.

     Altered by	Eric Fischer <enf@pobox.com>, July, 2000, to identify charac-
     ter codes and attempt to identify the languages of	non-ASCII files.

     Altered by	Reuben Thomas <rrt@sc3d.org>, 2007-2011, to improve MIME sup-
     port, merge MIME and non-MIME magic, support directories as well as files
     of	magic, apply many bug fixes, update and	fix a lot of magic, improve
     the build system, improve the documentation, and rewrite the Python bind-
     ings in pure Python.

     The list of contributors to the `magic' directory (magic files) is	too
     long to include here.  You	know who you are; thank	you.  Many contribu-
     tors are listed in	the source files.

LEGAL NOTICE
     Copyright (c) Ian F. Darwin, Toronto, Canada, 1986-1999.  Covered by the
     standard Berkeley Software	Distribution copyright;	see the	file COPYING
     in	the source distribution.

     The files tar.h and is_tar.c were written by John Gilmore from his	pub-
     lic-domain	tar(1) program,	and are	not covered by the above license.

RETURN CODE
     file returns 0 on success,	and non-zero on	error.

BUGS
     Please report bugs	and send patches to the	bug tracker at
     http://bugs.gw.com/ or the	mailing	list at	<file@mx.gw.com>.

TODO
     Fix output	so that	tests for MIME and APPLE flags are not needed all over
     the place,	and actual output is only done in one place. This needs	a
     design. Suggestion: push possible outputs on to a list, then pick the
     last-pushed (most specific, one hopes) value at the end, or use a default
     if	the list is empty. This	should not slow	down evaluation.

     Continue to squash	all magic bugs.	See Debian BTS for a good source.

     Store arbitrarily long strings, for example for %s	patterns, so that they
     can be printed out. Fixes Debian bug #271672. Would require more complex
     store/load	code in	apprentice.

     Add syntax	for relative offsets after current level (Debian bug #466037).

     Make file -ki work, i.e. give multiple MIME types.

     Add a zip library so we can peek inside Office2007	documents to figure
     out what they are.

     Add an option to print URLs for the sources of the	file descriptions.

AVAILABILITY
     You can obtain the	original author's latest version by anonymous FTP on
     ftp.astron.com in the directory /pub/file/file-X.YZ.tar.gz.

FreeBSD	10.1		       October 17, 2011			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | ENVIRONMENT | SEE ALSO | STANDARDS CONFORMANCE | MAGIC DIRECTORY | EXAMPLES | HISTORY | LEGAL NOTICE | RETURN CODE | BUGS | TODO | AVAILABILITY

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=file&manpath=FreeBSD+9.2-RELEASE>

home | help