1 ## README for file(1) Command and the libmagic(3) library ## 2 3 @(#) $File: README.md,v 1.7 2026/06/07 23:44:12 christos Exp $ 4 5 - Bug Tracker: <https://bugs.astron.com/> 6 - Build Status: <https://travis-ci.org/file/file> 7 - Download link: <ftp://ftp.astron.com/pub/file/> 8 - E-mail: <christos@astron.com> 9 - Fuzzing link: <https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:file> 10 - Home page: https://www.darwinsys.com/file/ 11 - Mailing List archives: <https://mailman.astron.com/pipermail/file/> 12 - Mailing List: <file@astron.com> 13 - Public repo: <https://github.com/file/file> 14 - Test framework: <https://github.com/file/file-tests> 15 16 Phone: Do not even think of telephoning me about this program. Send 17 cash first! 18 19 This is Release 5.x of Ian Darwin's (copyright but distributable) 20 file(1) command, an implementation of the Unix File(1) command. 21 It knows the 'magic number' of several thousands of file types. 22 This version is the standard "file" command for Linux, *BSD, and 23 other systems. (See "patchlevel.h" for the exact release number). 24 25 The major changes for 5.x are CDF file parsing, indirect magic, 26 name/use (recursion) and overhaul in mime and ascii encoding 27 handling. 28 29 The major feature of 4.x is the refactoring of the code into a 30 library, and the re-write of the file command in terms of that 31 library. The library itself, libmagic can be used by 3rd party 32 programs that wish to identify file types without having to fork() 33 and exec() file. The prime contributor for 4.0 was Mans Rullgard. 34 35 UNIX is a trademark of UNIX System Laboratories. 36 37 The prime contributor to Release 3.8 was Guy Harris, who put in 38 megachanges including byte-order independence. 39 40 The prime contributor to Release 3.0 was Christos Zoulas, who put 41 in hundreds of lines of source code changes, including his own 42 ANSIfication of the code (I liked my own ANSIfication better, but 43 his (__P()) is the "Berkeley standard" way of doing it, and I wanted 44 UCB to include the code...), his HP-like "indirection" (a feature 45 of the HP file command, I think), and his mods that finally got 46 the uncompress (-z) mode finished and working. 47 48 This release has compiled in numerous environments; see PORTING 49 for a list and problems. 50 51 This fine freeware file(1) follows the USG (System V) model of the 52 file command, rather than the Research (V7) version or the V7-derived 53 4.[23] Berkeley one. That is, the file /etc/magic contains much of 54 the ritual information that is the source of this program's power. 55 My version knows a little more magic (including tar archives) than 56 System V; the /etc/magic parsing seems to be compatible with the 57 (poorly documented) System V /etc/magic format (with one exception; 58 see the man page). 59 60 In addition, the /etc/magic file is built from a subdirectory 61 for easier(?) maintenance. I will act as a clearinghouse for 62 magic numbers assigned to all sorts of data files that 63 are in reasonable circulation. Send your magic numbers, 64 in magic(5) format please, to the maintainer, Christos Zoulas. 65 66 COPYING - read this first. 67 * `ChangeLog` - log of important changes 68 * `README.md` - read this second (you are currently reading this file). 69 * `INSTALL` - read on how to install 70 * `src/apprentice.c` - parses /etc/magic to learn magic 71 * `src/apptype.c` - used for OS/2 specific application type magic 72 * `src/ascmagic.c` - third & last set of tests, based on hardwired assumptions. 73 * `src/asctime_r.c` - replacement for OS's that don't have it. 74 * `src/asprintf.c` - replacement for OS's that don't have it. 75 * `src/buffer.c` - buffer handling functions. 76 * `src/cdf.[ch]` - parser for Microsoft Compound Document Files 77 * `src/cdf_time.c` - time converter for CDF. 78 * `src/compress.c` - handles decompressing files to look inside. 79 * `src/ctime_r.c` - replacement for OS's that don't have it. 80 * `src/der.[ch]` - parser for Distinguished Encoding Rules 81 * `src/dprintf.c` - replacement for OS's that don't have it. 82 * `src/elfclass.h` - common code for elf 32/64. 83 * `src/encoding.c` - handles unicode encodings 84 * `src/file.c` - the main program 85 * `src/file.h` - header file 86 * `src/file_opts.h` - list of options 87 * `src/fmtcheck.c` - replacement for OS's that don't have it. 88 * `src/fsmagic.c` - first set of tests the program runs, based on filesystem info 89 * `src/funcs.c` - utilility functions 90 * `src/getline.c` - replacement for OS's that don't have it. 91 * `src/getopt_long.c` - replacement for OS's that don't have it. 92 * `src/gmtime_r.c` - replacement for OS's that don't have it. 93 * `src/is_csv.c` - knows about Comma Separated Value file format (RFC 4180). 94 * `src/is_json.c` - knows about JavaScript Object Notation format (RFC 8259). 95 * `src/is_simh.c` - knows about SIMH tape file format. 96 * `src/is_tar.c, tar.h` - knows about Tape ARchive format (courtesy John Gilmore). 97 * `src/landlock.c` - linux landlock protection 98 * `src/localtime_r.c` - replacement for OS's that don't have it. 99 * `src/magic.h.in` - source file for magic.h 100 * `src/mygetopt.h` - replacement for OS's that don't have it. 101 * `src/magic.c` - the libmagic api 102 * `src/names.h` - header file for ascmagic.c 103 * `src/pread.c` - replacement for OS's that don't have it. 104 * `src/print.c` - print results, errors, warnings. 105 * `src/readcdf.c` - CDF wrapper. 106 * `src/readelf.[ch]` - Stand-alone elf parsing code. 107 * `src/softmagic.c` - 2nd set of tests, based on /etc/magic 108 * `src/swap.h` - byte swapping 109 * `src/swap.c` - byte swapping 110 * `src/mygetopt.h` - replacement for OS's that don't have it. 111 * `src/seccomp.c` - linux seccomp protection 112 * `src/strcasestr.c` - replacement for OS's that don't have it. 113 * `src/strlcat.c` - replacement for OS's that don't have it. 114 * `src/strlcpy.c` - replacement for OS's that don't have it. 115 * `src/strndup.c` - replacement for OS's that don't have it. 116 * `src/tar.h` - tar file definitions 117 * `src/vasprintf.c` - for systems that don't have it. 118 * `doc/file.man` - man page for the command 119 * `doc/magic.man` - man page for the magic file, courtesy Guy Harris. 120 Install as magic.4 on USG and magic.5 on V7 or Berkeley; cf Makefile. 121 122 Magdir - directory of /etc/magic pieces 123 ------------------------------------------------------------------------------ 124 125 If you submit a new magic entry please make sure you read the following 126 guidelines: 127 128 - Initial match is preferably at least 32 bits long, and is a _unique_ match 129 - If this is not feasible, use additional check 130 - Match of <= 16 bits are not accepted 131 - Delay printing string as much as possible, don't print output too early 132 - Avoid printf arbitrary byte as string, which can be a source of 133 crash and buffer overflow 134 135 - Provide complete information with entry: 136 * One line short summary 137 * Optional long description 138 * File extension, if applicable 139 * Full name and contact method (for discussion when entry has problem) 140 * Further reference, such as documentation of format 141 142 gpg for dummies: 143 ------------------------------------------------------------------------------ 144 145 ``` 146 $ gpg --verify file-X.YY.tar.gz.asc file-X.YY.tar.gz 147 gpg: assuming signed data in `file-X.YY.tar.gz' 148 gpg: Signature made WWW MMM DD HH:MM:SS YYYY ZZZ using DSA key ID KKKKKKKK 149 ``` 150 151 To download the key: 152 153 ``` 154 $ gpg --keyserver hkp://keys.gnupg.net --recv-keys KKKKKKKK 155 ``` 156 ------------------------------------------------------------------------------ 157 158 159 Parts of this software were developed at SoftQuad Inc., developers 160 of SGML/HTML/XML publishing software, in Toronto, Canada. 161 SoftQuad was swallowed up by Corel in 2002 and does not exist any longer. 162
Indexes created Sat Jun 13 00:24:39 UTC 2026