david/Repository
1
0
Fork 0
Code Releases Activity

Auto-commit: 2025-10-31 08:58:35

Browse Source
This commit is contained in:
David Wuibaille
2025-10-31 08:58:36 +01:00
parent 7d94414992
commit 7cc3011354
1088 changed files with 193455 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

443
Tools/UniExtractRC3/UniExtract/bin/file/man/cat1/file.1.txt Normal file
View File

@@ -0,0 +1,443 @@
FILE(1) BSD General Commands Manual FILE(1)
NAME
file -- determine file type
SYNOPSIS
file [-bchikLnNprsvz] [--mime-type] [--mime-encoding]
[-f namefile] [-F separator] [-m magicfiles] file
file -C [-m magicfile]
file [--help]
DESCRIPTION
This manual page documents version 5.03 of the file com-
mand.
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). Excep-
tions are well-known file formats (core files, tar ar-
chives) that are known to contain binary data. When modi-
fying 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 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 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 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 the compiled magic
file c:/progra~1/file/share/misc/magic.mgc, or the files
in the directory c:/progra~1/file/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 transla-
tion 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 particu-
lar 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 pro-
gram. 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) ar-
chives).
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, --checking-printout
Cause a checking printout of the parsed form of
the magic file. This is usually used in conjunc-
tion with the -m flag to debug a new magic file
before installing it.
-C, --compile
Write a magic.mgc output file that contains a pre-
parsed version of the magic file or directory.
-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).
text
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
Looks for known tokens inside text files.
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, --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.
-F, --separator separator
Use the specified string as the separator between
the filename and the file result returned.
Defaults to `:'.
-h, --no-dereference
option causes symlinks not to be followed (on sys-
tems 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'. 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
`magic' file. (See the FILES section, below).
--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. Subse-
quent matches will be have the string `\012- '
prepended. (If you want a newline, see the `-r'
option.)
-L, --dereference
option causes symlinks to be followed, as the
like-named option in ls(1) (on systems that sup-
port symbolic links). This is the default if the
environment variable POSIXLY_CORRECT is defined.
-m, --magic-file 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.
-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.
-N, --no-pad
Don't pad filenames so that they align in the out-
put.
-p, --preserve-date
On systems that support utime(2) or utimes(2),
attempt to preserve the access time of files ana-
lyzed, 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 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 parti-
tions.
-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
c:/progra~1/file/share/misc/magic.mgc Default compiled
list of magic.
c:/progra~1/file/share/misc/magic Directory contain-
ing 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. 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), strings(1), od(1), hexdump(1,) file(1posix)
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.
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. My version differs from Sun's only in
minor ways. It includes the extension of the `&' opera-
tor, 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 consolida-
tion of magic file entries will be distributed periodi-
cally.
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 file
command uses a magic file, keep the old magic file around
for comparison purposes (rename it to
c:/progra~1/file/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 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 any-
body else's source code.
John Gilmore revised the code extensively, making it bet-
ter than the first version. Geoff Collyer found several
inadequacies and provided some magic file entries. Con-
tributions by the `&' operator by Rob McMahon, cudcv@war-
wick.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 alterna-
tive magic file and internal logic.
Altered by Eric Fischer (enf@pobox.com), July, 2000, to
identify character codes and attempt to identify the lan-
guages of non-ASCII files.
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.
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 LEGAL.NOTICE in the source distri-
bution.
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.
BUGS
There must be a better way to automate the construction of
the Magic file from all the glop in Magdir. What is it?
file uses several algorithms that favor speed over accu-
racy, thus it can be misled about the contents of text
files.
The support for text files (primarily for programming lan-
guages) is simplistic, inefficient and requires recompila-
tion to update.
The list of keywords in ascmagic probably belongs in the
Magic file. This could be done by using some keyword like
`*' for the offset value.
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?
The program should provide a way to give an estimate of
`how good' a guess is. We end up removing guesses (e.g.
`Fromas first 5 chars of file) because' they are not as
good as other guesses (e.g. `Newsgroups:' versus
`Return-Path:' ). Still, if the others don't pan out, it
should be possible to use the first guess.
This manual page, and particularly this section, is too
long.
RETURN CODE
file returns 0 on success, and non-zero on error.
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 October 9, 2008 BSD