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FILE(1)                   BSD General Commands ManualFILE(1)NAME     file -- determine file typeSYNOPSIS     file [-bcdEhiklLNnprsSvzZ0] [--apple] [--extension] [--mime-encoding]          [--mime-type] [-e testname] [-F separator] [-f namefile]          [-m magicfiles] [-P name=value] file ...     file -C [-m magicfiles]     file [--help]DESCRIPTION     This manual page documents version 5.38 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 adding     local definitions to /etc/magic, 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 astat(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 de-     scribed in this way.  The information identifying these files is read     from /etc/magic and 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 ex-     amined 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" be-     cause 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 addition,     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 contain embedded es-     cape 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 atroff(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 astar(1) archives, JSON     files).     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     --apple             Causes the file command to output the file type and creator code             as used by older MacOS versions.  The code consists of eight let-             ters, the first describing the file type, the latter the creator.             This option works properly only for file formats that have the             apple-style output defined.     -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.     -d      Prints internal debugging information to stderr.     -E      On filesystem errors (file not found etc), instead of handling             the error as regular output as POSIX mandates and keep going, is-             sue an error message and exit.     -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.             csv       Checks Comma Separated Value files.             elf       Prints ELF file details, provided soft magic tests are                       enabled and the elf magic is found.             json      Examines JSON (RFC-7159) files by parsing them for com-                       pliance.             soft      Consults magic files.             tar       Examines tar files by verifying the checksum of the 512                       byte tar header.  Excluding this test can provide more                       detailed content description by using the soft magic                       method.             text      A synonym for 'ascii'.     --extension             Print a slash-separated list of valid extensions for the file             type found.     -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 un-             wrapped 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.)  The magic pattern with the highest             strength (see the -l option) comes first.     -l, --list             Shows a list of patterns and their strength sorted descending bymagic(5) strength which is used for the matching (see also the -k             option).     -L, --dereference             option causes symlinks to be followed, as the like-named option             inls(1) (on systems that support symbolic links).  This is the             default if the environment variable POSIXLY_CORRECT is defined.     -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 supportutime(3) orutimes(2), attempt to pre-             serve the access time of files analyzed, to pretend that file             never read them.     -P, --parameter name=value             Set various parameter limits.                   Name         Default    Explanation                   indir        15         recursion limit for indirect magic                   name         30         use count limit for name/use magic                   elf_notes    256        max ELF notes processed                   elf_phnum    128        max ELF program sections processed                   elf_shnum    32768      max ELF sections processed                   regex        8192       length limit for regex searches                   bytes        1048576    max number of bytes to read from                                                                          file     -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 whichstat(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 op-             tion also causes file to disregard the file size as reported bystat(2) since on some systems it reports a zero size for raw disk             partitions.     -S, --no-sandbox             On systems where libseccomp             (https://github.com/seccomp/libseccomp) is available, the -S flag             disables sandboxing which is enabled by default.  This option is             needed for file to execute external decompressing programs, i.e.             when the -z flag is specified and the built-in decompressors are             not available.  On systems where sandboxing is not available,             this option has no effect.             Note: This Debian version of file was built without seccomp sup-             port, so this option has no effect.     -v, --version             Print the version of the program and exit.     -z, --uncompress             Try to look inside compressed files.     -Z, --uncompress-noreport             Try to look inside compressed files, but report information about             the contents only not the compression.     -0, --print0             Output a null character '\0' after the end of the filename.  Nice             tocut(1) the output.  This does not affect the separator, which             is still printed.             If this option is repeated more than once, then file prints just             the filename followed by a NUL followed by the description (or             ERROR: text) followed by a second NUL for each entry.     --help  Print a help message and exit.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.  The environment variable POSIXLY_CORRECT controls (on systems     that support symbolic links), whether file will attempt to follow sym-     links or not.  If set, then file follows symlink, otherwise it does not.     This is also controlled by the -L and -h options.FILES     /usr/share/misc/magic.mgc  Default compiled list of magic.     /usr/share/misc/magic      Directory containing default magic files.EXIT STATUS     file will exit with 0 if the operation was successful or >0 if an error     was encountered.  The following errors cause diagnostic messages, but     don't affect the program exit code (as POSIX requires), unless -E is     specified:           o   A file cannot be found           o   There is no permission to read a file           o   The file type cannot be determinedEXAMPLES           $ 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-fileSEE ALSOhexdump(1),od(1),strings(1),magic(5)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 strippedSECURITY     On systems where libseccomp (https://github.com/seccomp/libseccomp) is     available, file is enforces limiting system calls to only the ones neces-     sary for the operation of the program.  This enforcement does not provide     any security benefit when file is asked to decompress input files running     external programs with the -z option.  To enable execution of external     decompressors, one needs to disable sandboxing using the -S flag.MAGIC DIRECTORY     The magic file entries have been collected from various sources, mainly     USENET, and contributed by various authors.  Christos Zoulas (address be-     low) will collect additional or corrected magic file entries.  A consoli-     dation 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.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 of the '&' operator by Rob McMa-     hon, <cudcv@warwick.ac.uk>, 1989.     Guy Harris, <guy@netapp.com>, made many changes from 1993 to the present.     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-domaintar(1) program, and are not covered by the above license.BUGS     Please report bugs and send patches to the bug tracker at     https://bugs.astron.com/ or the mailing list at <file@astron.com> (visit     https://mailman.astron.com/mailman/listinfo/file first to subscribe).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 de-     sign.  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.     The handling of MAGIC_CONTINUE and printing \012- between entries is     clumsy and complicated; refactor and centralize.     Some of the encoding logic is hard-coded in encoding.c and can be moved     to the magic files if we had a !:charset annotation     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.  This can be done by allo-     cating strings in a string pool, storing the string pool at the end of     the magic file and converting all the string pointers to relative offsets     from the string pool.     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 print     more details about their contents.     Add an option to print URLs for the sources of the file descriptions.     Combine script searches and add a way to map executable names to MIME     types (e.g. have a magic value for !:mime which causes the resulting     string to be looked up in a table).  This would avoid adding the same     magic repeatedly for each new hash-bang interpreter.     When a file descriptor is available, we can skip and adjust the buffer     instead of the hacky buffer management we do now.     Fix "name" and "use" to check for consistency at compile time (duplicate     "name", "use" pointing to undefined "name" ).  Make "name" / "use" more     efficient by keeping a sorted list of names.  Special-case ^ to flip en-     dianness in the parser so that it does not have to be escaped, and docu-     ment it.     If the offsets specified internally in the file exceed the buffer size (     HOWMANY variable in file.h), then we don't seek to that offset, but we     give up.  It would be better if buffer managements was done when the file     descriptor is available so move around the file.  One must be careful     though because this has performance (and thus security considerations).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.BSD                              July 13, 2019                             BSD