 @@ -1,550 +1,550 @@
 .\" $File: file.man,v 1.73 2008/02/19 17:58:00 rrt Exp $
 .Dd February 19, 2008
 .Dt FILE 1
 .Os
 .Sh NAME
 .Nm file
 .Nd determine file type
 .Sh SYNOPSIS
 .Nm
 .Op Fl bchikLnNprsvz
 .Op Fl -mime-type
 .Op Fl -mime-encoding
 .Op Fl f Ar namefile
 .Op Fl F Ar separator
 .Op Fl m Ar magicfiles
 .Ar file
 .Nm
 .Fl C
 .Op Fl m Ar magicfile
 .Nm
 .Op Fl -help
 .Sh DESCRIPTION
 This manual page documents version 4.26 of the
 .Nm
 command.
 .Pp
 .Nm
 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
 .Em first
 test that succeeds causes the file type to be printed.
 .Pp
 The type printed will usually contain one of the words
 .Em text
 (the file contains only
 printing characters and a few common control
 characters and is probably safe to read on an
 .Dv ASCII
 terminal),
 .Em executable
 (the file contains the result of compiling a program
 in a form understandable to some
 .Dv UNIX
 kernel or another),
 or
 .Em data
 meaning anything else (data is usually
 .Sq 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
 .Em "preserve these keywords" .
 Users depend on knowing that all the readable files in a directory
 have the word
 .Dq text
 printed.
 Don't do as Berkeley did and change
 .Dq shell commands text
 to
 .Dq shell script .
 .Pp
 The filesystem tests are based on examining the return from a
 .Xr 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 system 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
 .In sys/stat.h .
 .Pp
 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)
 .Dv a.out
 file, whose format is defined in
 .In elf.h ,
 .In a.out.h
 and possibly
 .In exec.h
 in the standard include directory.
 These files have a
 .Sq "magic number"
 stored in a particular place
 near the beginning of the file that tells the
 .Dv UNIX operating system
 that the file is a binary executable, and which of several types thereof.
 The concept of a
 .Sq "magic"
 has been applied by extension to data files.
 Any file with some invariant 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
 .Pa /usr/tools/share/file/magic.mgc ,
 or the files in the directory
 .Pa /usr/tools/share/file/magic
 if the compiled file does not exist. In addition, if
 .Pa $HOME/.magic.mgc
 or
 .Pa $HOME/.magic
 exists, it will be used in preference to the system magic files.
 .Pp
 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
 .Dq text
 because they will be mostly readable on nearly any terminal;
 UTF-16 and EBCDIC are only
 .Dq character data
 because, while
 they contain text, it is text that will require translation
 before it can be read.
 In addition,
 .Nm
 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 contain embedded escape sequences or overstriking
 will also be identified.
 .Pp
 Once
 .Nm
 has determined the character set used in a text-type file,
 it will
 attempt to determine in what language the file is written.
 The language tests look for particular strings (cf.
 .In names.h
 ) that can appear anywhere in the first few blocks of a file.
 For example, the keyword
 .Em .br
 indicates that the file is most likely a
 .Xr troff 1
 input file, just as the keyword
 .Em 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
 .Xr tar 1
 archives).
 .Pp
 Any file that cannot be identified as having been written
 in any of the character sets listed above is simply said to be
 .Dq data .
 .Sh OPTIONS
 .Bl -tag -width indent
 .It Fl b , -brief
 Do not prepend filenames to output lines (brief mode).
 .It Fl c , -checking-printout
 Cause a checking printout of the parsed form of the magic file.
 This is usually used in conjunction with the
 .Fl m
 flag to debug a new magic file before installing it.
 .It Fl C , -compile
 Write a
 .Pa magic.mgc
 output file that contains a pre-parsed version of the magic file or directory.
 .It Fl e , -exclude Ar testname
 Exclude the test named in
 .Ar testname
 from the list of tests made to determine the file type. Valid test names
 are:
-.Bl -tag -width
+.Bl -tag -width compress
 .It apptype
 Check for
 .Dv EMX
 application type (only on EMX).
 .It ascii
 Check for various types of ascii files.
 .It compress
 Don't look for, or inside compressed files.
 .It elf
 Don't print elf details.
 .It fortran
 Don't look for fortran sequences inside ascii files.
 .It soft
 Don't consult magic files.
 .It tar
 Don't examine tar files.
 .It token
 Don't look for known tokens inside ascii files.
 .It troff
 Don't look for troff sequences inside ascii files.
 .El
 .It Fl f , -files-from Ar namefile
 Read the names of the files to be examined from
 .Ar namefile
 (one per line)
 before the argument list.
 Either
 .Ar namefile
 or at least one filename argument must be present;
 to test the standard input, use
 .Sq -
 as a filename argument.
 .It Fl F , -separator Ar separator
 Use the specified string as the separator between the filename and the
 file result returned. Defaults to
 .Sq \&: .
 .It Fl h , -no-dereference
 option causes symlinks not to be followed
 (on systems that support symbolic links). This is the default if the
 environment variable
 .Dv POSIXLY_CORRECT
 is not defined.
 .It Fl i , -mime
 Causes the file command to output mime type strings rather than the more
 traditional human readable ones. Thus it may say
 .Dq text/plain charset=us-ascii
 rather than
 .Dq ASCII text .
 In order for this option to work, file changes the way
 it handles files recognized by the command itself (such as many of the
 text file types, directories etc), and makes use of an alternative
 .Dq magic
 file.
 (See
 .Dq FILES
 section, below).
 .It Fl -mime-type , -mime-encoding
 Like
 .Fl i ,
 but print only the specified element(s).
 .It Fl k , -keep-going
 Don't stop at the first match, keep going. Subsequent matches will be
 have the string
 .Dq "\[rs]012\- "
 prepended.
 (If you want a newline, see the
 .Dq "\-r"
 option.)
 .It Fl L , -dereference
 option causes symlinks to be followed, as the like-named option in
 .Xr ls 1
 (on systems that support symbolic links).
 This is the default if the environment variable
 .Dv POSIXLY_CORRECT
 is defined.
 .It Fl m , -magic-file Ar list
 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.
 .It Fl 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.
 .It Fl N , -no-pad
 Don't pad filenames so that they align in the output.
 .It Fl p , -preserve-date
 On systems that support
 .Xr utime 2
 or
 .Xr utimes 2 ,
 attempt to preserve the access time of files analyzed, to pretend that
 .Nm
 never read them.
 .It Fl r , -raw
 Don't translate unprintable characters to \eooo.
 Normally
 .Nm
 translates unprintable characters to their octal representation.
 .It Fl s , -special-files
 Normally,
 .Nm
 only attempts to read and determine the type of argument files which
 .Xr stat 2
 reports are ordinary files.
 This prevents problems, because reading special files may have peculiar
 consequences.
 Specifying the
 .Fl s
 option causes
 .Nm
 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
 .Nm
 to disregard the file size as reported by
 .Xr stat 2
 since on some systems it reports a zero size for raw disk partitions.
 .It Fl v , -version
 Print the version of the program and exit.
 .It Fl z , -uncompress
 Try to look inside compressed files.
 .It Fl 0 , -print0
 Output a null character
 .Sq \e0
 after the end of the filename. Nice to
 .Xr cut 1
 the output. This does not affect the separator which is still printed.
 .It Fl -help
 Print a help message and exit.
 .El
 .Sh FILES
 .Bl -tag -width /usr/tools/share/file/magic.mgc -compact
 .It Pa /usr/tools/share/file/magic.mgc
 Default compiled list of magic.
 .It Pa /usr/tools/share/file/magic
 Directory containing default magic files.
 .El
 .Sh ENVIRONMENT
 The environment variable
 .Dv MAGIC
 can be used to set the default magic file name.
 If that variable is set, then
 .Nm
 will not attempt to open
 .Pa $HOME/.magic .
 .Nm
 adds
 .Dq .mgc
 to the value of this variable as appropriate.
 The environment variable
 .Dv POSIXLY_CORRECT
 controls (on systems that support symbolic links), whether
 .Nm
 will attempt to follow symlinks or not. If set, then
 .Nm
 follows symlink, otherwise it does not. This is also controlled
 by the
 .Fl L
 and
 .Fl h
 options.
 .Sh SEE ALSO
 .Xr magic 4 ,
 .Xr strings 1 ,
 .Xr od 1 ,
 .Xr hexdump 1,
 .Xr file 1posix
 .Sh 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 produce
 different (albeit more accurate) output in many cases.
 .\" URL: http://www.opengroup.org/onlinepubs/009695399/utilities/file.html
 .Pp
 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,
 .Bd -literal -offset indent
 >10	string	language impress\ 	(imPRESS data)
 .Ed
 .Pp
 in an existing magic file would have to be changed to
 .Bd -literal -offset indent
 >10	string	language\e impress	(imPRESS data)
 .Ed
 .Pp
 In addition, in this version, if a pattern string contains a backslash,
 it must be escaped.
 For example
 .Bd -literal -offset indent
 	string		\ebegindata	Andrew Toolkit document
 .Ed
 .Pp
 in an existing magic file would have to be changed to
 .Bd -literal -offset indent
 	string		\e\ebegindata	Andrew Toolkit document
 .Ed
 .Pp
 SunOS releases 3.2 and later from Sun Microsystems include a
 .Nm
 command derived from the System V one, but with some extensions.
 My version differs from Sun's only in minor ways.
 It includes the extension of the
 .Sq &
 operator, used as,
 for example,
 .Bd -literal -offset indent
 >16	long&0x7fffffff	>0		not stripped
 .Ed
 .Sh 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 consolidation of magic file entries
 will be distributed periodically.
 .Pp
 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 incorrect.
 If your old
 .Nm
 command uses a magic file,
 keep the old magic file around for comparison purposes
 (rename it to
 .Pa /usr/tools/share/file/magic.orig ).
 .Sh EXAMPLES
 .Bd -literal -offset indent
 $ 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
 .Ed
 .Sh HISTORY
 There has been a
 .Nm
 command in every
 .Dv UNIX since at least Research Version 4
 (man page dated November, 1973).
 The System V version introduced one significant major change:
 the external list of magic types.
 This slowed the program down slightly but made it a lot more flexible.
 .Pp
 This program, based on the System V version,
 was written by Ian Darwin <ian@darwinsys.com>
 without looking at anybody else's source code.
 .Pp
 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 McMahon, cudcv@warwick.ac.uk, 1989.
 .Pp
 Guy Harris, guy@netapp.com, made many changes from 1993 to the present.
 .Pp
 Primary development and maintenance from 1990 to the present by
 Christos Zoulas (christos@astron.com).
 .Pp
 Altered by Chris Lowth, chris@lowth.com, 2000:
 Handle the
 .Fl i
 option to output mime type strings, using an alternative
 magic file and internal logic.
 .Pp
 Altered by Eric Fischer (enf@pobox.com), July, 2000,
 to identify character codes and attempt to identify the languages
 of non-ASCII files.
 .Pp
 Altered by Reuben Thomas (rrt@sc3d.org), 2007 to 2008, to improve MIME
 support and merge MIME and non-MIME magic, support directories as well
 as files of magic, apply many bug fixes and improve the build system.
 .Pp
 The list of contributors to the
 .Dq magic
 directory (magic files)
 is too long to include here.
 You know who you are; thank you.
 Many contributors are listed in the source files.
 .Sh LEGAL NOTICE
 Copyright (c) Ian F. Darwin, Toronto, Canada, 1986-1999.
 Covered by the standard Berkeley Software Distribution copyright; see the file
 LEGAL.NOTICE in the source distribution.
 .Pp
 The files
 .Dv tar.h
 and
 .Dv is_tar.c
 were written by John Gilmore from his public-domain
 .Xr tar 1
 program, and are not covered by the above license.
 .Sh BUGS
 .Pp
 There must be a better way to automate the construction of the Magic
 file from all the glop in Magdir.
 What is it?
 .Pp
 .Nm
 uses several algorithms that favor speed over accuracy,
 thus it can be misled about the contents of
 text
 files.
 .Pp
 The support for text files (primarily for programming languages)
 is simplistic, inefficient and requires recompilation to update.
 .Pp
 The list of keywords in
 .Dv ascmagic
 probably belongs in the Magic file.
 This could be done by using some keyword like
 .Sq *
 for the offset value.
 .Pp
 Complain about conflicts in the magic file entries.
 Make a rule that the magic entries sort based on file offset rather
 than position within the magic file?
 .Pp
 The program should provide a way to give an estimate
 of
 .Dq how good
 a guess is.
 We end up removing guesses (e.g.
 .Dq From\
 as first 5 chars of file) because
 they are not as good as other guesses (e.g.
 .Dq Newsgroups:
 versus
 .Dq Return-Path:
 ).
 Still, if the others don't pan out, it should be possible to use the
 first guess.
 .Pp
 This manual page, and particularly this section, is too long.
 .Sh RETURN CODE
 .Nm
 returns 0 on success, and non-zero on error.
 .Sh AVAILABILITY
 You can obtain the original author's latest version by anonymous FTP
 on
 .Dv ftp.astron.com
 in the directory
 .Dv /pub/file/file-X.YZ.tar.gz