130 lines
5.3 KiB
Plaintext
130 lines
5.3 KiB
Plaintext
** README for file(1) Command **
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@(#) $File: README,v 1.40 2008/04/23 03:45:20 christos Exp $
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E-mail: christos@astron.com
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Mailing List: file@mx.gw.com
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Phone: Do not even think of telephoning me about this program. Send cash first!
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This is Release 4.x of Ian Darwin's (copyright but distributable)
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file(1) command. This version is the standard "file" command for Linux,
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*BSD, and other systems. (See "patchlevel.h" for the exact release number).
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The major feature of 4.x is the refactoring of the code into a library,
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and the re-write of the file command in terms of that library. The library
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itself, libmagic can be used by 3rd party programs that wish to identify
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file types without having to fork() and exec() file. The prime contributor
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for 4.0 was M\xe5ns Rullg\xe5rd.
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UNIX is a trademark of UNIX System Laboratories.
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The prime contributor to Release 3.8 was Guy Harris, who put in megachanges
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including byte-order independence.
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The prime contributor to Release 3.0 was Christos Zoulas, who put
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in hundreds of lines of source code changes, including his own
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ANSIfication of the code (I liked my own ANSIfication better, but
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his (__P()) is the "Berkeley standard" way of doing it, and I wanted UCB
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to include the code...), his HP-like "indirection" (a feature of
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the HP file command, I think), and his mods that finally got the
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uncompress (-z) mode finished and working.
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This release has compiled in numerous environments; see PORTING
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for a list and problems.
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This fine freeware file(1) follows the USG (System V) model of the file
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command, rather than the Research (V7) version or the V7-derived 4.[23]
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Berkeley one. That is, the file /etc/magic contains much of the ritual
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information that is the source of this program's power. My version
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knows a little more magic (including tar archives) than System V; the
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/etc/magic parsing seems to be compatible with the (poorly documented)
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System V /etc/magic format (with one exception; see the man page).
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In addition, the /etc/magic file is built from a subdirectory
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for easier(?) maintenance. I will act as a clearinghouse for
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magic numbers assigned to all sorts of data files that
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are in reasonable circulation. Send your magic numbers,
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in magic(5) format please, to the maintainer, Christos Zoulas.
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COPYING - read this first.
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README - read this second (you are currently reading this file).
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PORTING - read this only if the program won't compile.
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Makefile - read this next, adapt it as needed (particularly
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the location of the old existing file command and
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the man page layouts), type "make" to compile,
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"make try" to try it out against your old version.
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Expect some diffs, particularly since your original
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file(1) may not grok the embedded-space ("\ ") in
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the current magic file, or may even not use the
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magic file.
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apprentice.c - parses /etc/magic to learn magic
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ascmagic.c - third & last set of tests, based on hardwired assumptions.
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core - not included in distribution due to mailer limitations.
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debug.c - includes -c printout routine
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file.1 - man page for the command
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magic.4 - man page for the magic file, courtesy Guy Harris.
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Install as magic.4 on USG and magic.5 on V7 or Berkeley; cf Makefile.
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file.c - main program
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file.h - header file
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fsmagic.c - first set of tests the program runs, based on filesystem info
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is_tar.c, tar.h - knows about tarchives (courtesy John Gilmore).
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magdir - directory of /etc/magic pieces
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magdir/Makefile - ADJUST THIS FOR YOUR CONFIGURATION
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names.h - header file for ascmagic.c
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softmagic.c - 2nd set of tests, based on /etc/magic
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readelf.[ch] - Stand-alone elf parsing code.
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compress.c - on-the-fly decompression.
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print.c - print results, errors, warnings.
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------------------------------------------------------------------------------
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If you submit a new magic entry please make sure you read the following
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guidelines:
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- Initial match is preferably at least 32 bits long, and is a _unique_ match
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- If this is not feasible, use additional check
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- Match of <= 16 bits are not accepted
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- Delay printing string as much as possible, don't print output too early
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- Avoid printf arbitrary byte as string, which can be a source of
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crash and buffer overflow
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- Provide complete information with entry:
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* One line short summary
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* Optional long description
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* File extension, if applicable
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* Full name and contact method (for discussion when entry has problem)
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* Further reference, such as documentation of format
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------------------------------------------------------------------------------
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You can download the latest version of file from:
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ftp://ftp.astron.com/pub/file/
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If your gzip sometimes fails to decompress things complaining about a short
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file, apply this patch [which is going to be in the next version of gzip]:
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*** - Tue Oct 29 02:06:35 1996
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--- util.c Sun Jul 21 21:51:38 1996
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*** 106,111 ****
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--- 108,114 ----
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if (insize == 0) {
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if (eof_ok) return EOF;
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+ flush_window();
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read_error();
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}
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bytes_in += (ulg)insize;
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Parts of this software were developed at SoftQuad Inc., developers
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of SGML/HTML/XML publishing software, in Toronto, Canada.
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SoftQuad was swallowed up by Corel in 2002
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and does not exist any longer.
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From: Kees Zeelenberg
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An MS-Windows (Win32) port of File-4.17 is available from
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http://gnuwin32.sourceforge.net/
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File is an implementation of the Unix File(1) command.
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It knows the 'magic number' of several thousands of file types.
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