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 +==== Manuel de la commande "​file"​ ====
 +
 +<​code>​
 +FILE(1) ​                                               BSD General Commands Manual ​                                              ​FILE(1)
 +
 +NAME
 +     file — determine file type
 +
 +SYNOPSIS
 +     file [-bcEhiklLNnprsvz0] [--apple] [--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 5.22 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 contains 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 defini‐
 +     tions 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 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 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
 +     <​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 exe‐
 +     ​cutable (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 oper‐
 +     ating system that the file is a binary executable, and which of several types thereof. ​ The concept of a “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 /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 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 Uni‐
 +     code, 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 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 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 language 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 indi‐
 +     cates a C program. ​ These tests are less reliable than the previous two groups, so they are performed last.  The language test rou‐
 +     tines 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
 +     ​--apple
 +             ​Causes the file command to output the file type and creator code as used by older MacOS versions. The code consists of
 +             eight letters, the first describing the file type, the latter the creator.
 +
 +     -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 ​     On filesystem errors (file not found etc), instead of handling the error as regular output as POSIX mandates and keep
 +             ​going,​ issue 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.
 +
 +             ​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 support 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
 +             ​newline,​ 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 by magic(4) 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 in ls(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 support utime(3) or utimes(2), attempt to preserve 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
 +
 +     -r, --raw
 +             ​Don'​t translate unprintable characters to \ooo.  Normally file translates unprintable characters to their octal representa‐
 +             tion.
 +
 +     -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 peculiar 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 separa‐
 +             tor, 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 appropriate. ​ However, file has to exist in order for
 +     ​file.mime to be considered. ​ 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 lan‐
 +     guage 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.
 +
 +     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 consolidation of magic file entries will be dis‐
 +     ​tributed 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 incorrect.
 +
 +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 ver‐
 +     sion introduced 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 McMahon, ⟨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 character codes and attempt to identify the languages of non-ASCII
 +     ​files.
 +
 +     ​Altered by Reuben Thomas ⟨rrt@sc3d.org⟩,​ 2007-2011, to improve MIME support, 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 bindings 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 contributors 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 public-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⟩ (visit
 +     ​http://​mx.gw.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 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.
 +
 +     ​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 inter‐
 +     ​preter.
 +
 +     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 endianness in the parser so that it does not have
 +     to be escaped, and document it.
 +
 +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                                                         ​December 16, 2014                                                        BSD
 +
 +</​code>​
  
  • man_de_file.txt
  • Dernière modification: 2016/03/30 15:33
  • (modification externe)