README revision 268515
1## README for file(1) Command ## 2 3 @(#) $File: README,v 1.48 2014/03/07 13:55:30 christos Exp $ 4 5Mailing List: file@mx.gw.com 6Mailing List archives: http://mx.gw.com/pipermail/file/ 7Bug tracker: http://bugs.gw.com/ 8E-mail: christos@astron.com 9 10[](https://travis-ci.org/file/file) 11 12Phone: Do not even think of telephoning me about this program. Send cash first! 13 14This is Release 5.x of Ian Darwin's (copyright but distributable) 15file(1) command, an implementation of the Unix File(1) command. 16It knows the 'magic number' of several thousands of file types. 17This version is the standard "file" command for Linux, 18*BSD, and other systems. (See "patchlevel.h" for the exact release number). 19 20You can download the latest version of the original sources for file from: 21 22 ftp://ftp.astron.com/pub/file/ 23 24A public read-only git repository of the same sources is available at: 25 26 https://github.com/file/file 27 28The major changes for 5.x are CDF file parsing, indirect magic, and 29overhaul in mime and ascii encoding handling. 30 31The major feature of 4.x is the refactoring of the code into a library, 32and the re-write of the file command in terms of that library. The library 33itself, libmagic can be used by 3rd party programs that wish to identify 34file types without having to fork() and exec() file. The prime contributor 35for 4.0 was Mans Rullgard. 36 37UNIX is a trademark of UNIX System Laboratories. 38 39The prime contributor to Release 3.8 was Guy Harris, who put in megachanges 40including byte-order independence. 41 42The prime contributor to Release 3.0 was Christos Zoulas, who put 43in hundreds of lines of source code changes, including his own 44ANSIfication of the code (I liked my own ANSIfication better, but 45his (__P()) is the "Berkeley standard" way of doing it, and I wanted UCB 46to include the code...), his HP-like "indirection" (a feature of 47the HP file command, I think), and his mods that finally got the 48uncompress (-z) mode finished and working. 49 50This release has compiled in numerous environments; see PORTING 51for a list and problems. 52 53This fine freeware file(1) follows the USG (System V) model of the file 54command, rather than the Research (V7) version or the V7-derived 4.[23] 55Berkeley one. That is, the file /etc/magic contains much of the ritual 56information that is the source of this program's power. My version 57knows a little more magic (including tar archives) than System V; the 58/etc/magic parsing seems to be compatible with the (poorly documented) 59System V /etc/magic format (with one exception; see the man page). 60 61In addition, the /etc/magic file is built from a subdirectory 62for easier(?) maintenance. I will act as a clearinghouse for 63magic numbers assigned to all sorts of data files that 64are in reasonable circulation. Send your magic numbers, 65in magic(5) format please, to the maintainer, Christos Zoulas. 66 67COPYING - read this first. 68README - read this second (you are currently reading this file). 69INSTALL - read on how to install 70 71src/apprentice.c - parses /etc/magic to learn magic 72src/apptype.c - used for OS/2 specific application type magic 73src/asprintf.c - replacement for OS's that don't have it. 74src/ascmagic.c - third & last set of tests, based on hardwired assumptions. 75src/asctime_r.c - for systems that don't have it. 76src/asprintf.c - for systems that don't have it. 77src/cdf.c - parser for Microsoft Compound Document Files 78src/cdf_time.c - time converter for CDF. 79src/compress.c - handles decompressing files to look inside. 80src/ctime_r.c - for systems that don't have it. 81src/encoding.c - handles unicode encodings 82src/file.c - the main program 83src/file.h - header file 84src/fsmagic.c - first set of tests the program runs, based on filesystem info 85src/funcs.c - utilility functions 86src/getopt_long.c - for systems that don't have it. 87src/getline.c - for systems that don't have it. 88src/is_tar.c, tar.h - knows about tarchives (courtesy John Gilmore). 89src/names.h - header file for ascmagic.c 90src/magic.c - the libmagic api 91src/print.c - print results, errors, warnings. 92src/readcdf.c - CDF wrapper. 93src/readelf.[ch] - Stand-alone elf parsing code. 94src/softmagic.c - 2nd set of tests, based on /etc/magic 95src/strlcat.c - for systems that don't have it. 96src/strlcpy.c - for systems that don't have it. 97src/vasprintf.c - for systems that don't have it. 98doc/file.man - man page for the command 99doc/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. 101 102Magdir - directory of /etc/magic pieces 103------------------------------------------------------------------------------ 104 105If you submit a new magic entry please make sure you read the following 106guidelines: 107 108- 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 114 115- 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 121 122------------------------------------------------------------------------------ 123 124Parts of this software were developed at SoftQuad Inc., developers 125of SGML/HTML/XML publishing software, in Toronto, Canada. 126SoftQuad was swallowed up by Corel in 2002 and does not exist any longer. 127
