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1 ## README for file(1) Command ##
3 @(#) $File: README,v 1.48 2014/03/07 13:55:30 christos Exp $
5 Mailing List: file@mx.gw.com
6 Mailing List archives: http://mx.gw.com/pipermail/file/
7 Bug tracker: http://bugs.gw.com/
8 E-mail: christos@astron.com
10 [](https://travis-ci.org/file/file)
12 Phone: Do not even think of telephoning me about this program. Send cash first!
14 This is Release 5.x of Ian Darwin's (copyright but distributable)
15 file(1) command, an implementation of the Unix File(1) command.
16 It knows the 'magic number' of several thousands of file types.
17 This version is the standard "file" command for Linux,
18 *BSD, and other systems. (See "patchlevel.h" for the exact release number).
20 You can download the latest version of the original sources for file from:
22 ftp://ftp.astron.com/pub/file/
24 A public read-only git repository of the same sources is available at:
26 https://github.com/file/file
28 The major changes for 5.x are CDF file parsing, indirect magic, and
29 overhaul in mime and ascii encoding handling.
31 The major feature of 4.x is the refactoring of the code into a library,
32 and the re-write of the file command in terms of that library. The library
33 itself, libmagic can be used by 3rd party programs that wish to identify
34 file types without having to fork() and exec() file. The prime contributor
35 for 4.0 was Mans Rullgard.
37 UNIX is a trademark of UNIX System Laboratories.
39 The prime contributor to Release 3.8 was Guy Harris, who put in megachanges
40 including byte-order independence.
42 The prime contributor to Release 3.0 was Christos Zoulas, who put
43 in hundreds of lines of source code changes, including his own
44 ANSIfication of the code (I liked my own ANSIfication better, but
45 his (__P()) is the "Berkeley standard" way of doing it, and I wanted UCB
46 to include the code...), his HP-like "indirection" (a feature of
47 the HP file command, I think), and his mods that finally got the
48 uncompress (-z) mode finished and working.
50 This release has compiled in numerous environments; see PORTING
51 for a list and problems.
53 This fine freeware file(1) follows the USG (System V) model of the file
54 command, rather than the Research (V7) version or the V7-derived 4.[23]
55 Berkeley one. That is, the file /etc/magic contains much of the ritual
56 information that is the source of this program's power. My version
57 knows a little more magic (including tar archives) than System V; the
58 /etc/magic parsing seems to be compatible with the (poorly documented)
59 System V /etc/magic format (with one exception; see the man page).
61 In addition, the /etc/magic file is built from a subdirectory
62 for easier(?) maintenance. I will act as a clearinghouse for
63 magic numbers assigned to all sorts of data files that
64 are in reasonable circulation. Send your magic numbers,
65 in magic(5) format please, to the maintainer, Christos Zoulas.
67 COPYING - read this first.
68 README - read this second (you are currently reading this file).
69 INSTALL - read on how to install
71 src/apprentice.c - parses /etc/magic to learn magic
72 src/apptype.c - used for OS/2 specific application type magic
73 src/asprintf.c - replacement for OS's that don't have it.
74 src/ascmagic.c - third & last set of tests, based on hardwired assumptions.
75 src/asctime_r.c - for systems that don't have it.
76 src/asprintf.c - for systems that don't have it.
77 src/cdf.c - parser for Microsoft Compound Document Files
78 src/cdf_time.c - time converter for CDF.
79 src/compress.c - handles decompressing files to look inside.
80 src/ctime_r.c - for systems that don't have it.
81 src/encoding.c - handles unicode encodings
82 src/file.c - the main program
83 src/file.h - header file
84 src/fsmagic.c - first set of tests the program runs, based on filesystem info
85 src/funcs.c - utilility functions
86 src/getopt_long.c - for systems that don't have it.
87 src/getline.c - for systems that don't have it.
88 src/is_tar.c, tar.h - knows about tarchives (courtesy John Gilmore).
89 src/names.h - header file for ascmagic.c
90 src/magic.c - the libmagic api
91 src/print.c - print results, errors, warnings.
92 src/readcdf.c - CDF wrapper.
93 src/readelf.[ch] - Stand-alone elf parsing code.
94 src/softmagic.c - 2nd set of tests, based on /etc/magic
95 src/strlcat.c - for systems that don't have it.
96 src/strlcpy.c - for systems that don't have it.
97 src/vasprintf.c - for systems that don't have it.
98 doc/file.man - man page for the command
99 doc/magic.man - man page for the magic file, courtesy Guy Harris.
100 Install as magic.4 on USG and magic.5 on V7 or Berkeley; cf Makefile.
102 Magdir - directory of /etc/magic pieces
103 ------------------------------------------------------------------------------
105 If you submit a new magic entry please make sure you read the following
106 guidelines:
108 - Initial match is preferably at least 32 bits long, and is a _unique_ match
109 - If this is not feasible, use additional check
110 - Match of <= 16 bits are not accepted
111 - Delay printing string as much as possible, don't print output too early
112 - Avoid printf arbitrary byte as string, which can be a source of
113 crash and buffer overflow
115 - Provide complete information with entry:
116 * One line short summary
117 * Optional long description
118 * File extension, if applicable
119 * Full name and contact method (for discussion when entry has problem)
120 * Further reference, such as documentation of format
122 ------------------------------------------------------------------------------
124 Parts of this software were developed at SoftQuad Inc., developers
125 of SGML/HTML/XML publishing software, in Toronto, Canada.
126 SoftQuad was swallowed up by Corel in 2002 and does not exist any longer.