1## README for file(1) Command and the libmagic(3) library ## 2 3 @(#) $File: README.md,v 1.4 2021/10/21 01:51:31 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 16Phone: Do not even think of telephoning me about this program. Send 17cash first! 18 19This is Release 5.x of Ian Darwin's (copyright but distributable) 20file(1) command, an implementation of the Unix File(1) command. 21It knows the 'magic number' of several thousands of file types. 22This version is the standard "file" command for Linux, *BSD, and 23other systems. (See "patchlevel.h" for the exact release number). 24 25The major changes for 5.x are CDF file parsing, indirect magic, 26name/use (recursion) and overhaul in mime and ascii encoding 27handling. 28 29The major feature of 4.x is the refactoring of the code into a 30library, and the re-write of the file command in terms of that 31library. The library itself, libmagic can be used by 3rd party 32programs that wish to identify file types without having to fork() 33and exec() file. The prime contributor for 4.0 was Mans Rullgard. 34 35UNIX is a trademark of UNIX System Laboratories. 36 37The prime contributor to Release 3.8 was Guy Harris, who put in 38megachanges including byte-order independence. 39 40The prime contributor to Release 3.0 was Christos Zoulas, who put 41in hundreds of lines of source code changes, including his own 42ANSIfication of the code (I liked my own ANSIfication better, but 43his (__P()) is the "Berkeley standard" way of doing it, and I wanted 44UCB to include the code...), his HP-like "indirection" (a feature 45of the HP file command, I think), and his mods that finally got 46the uncompress (-z) mode finished and working. 47 48This release has compiled in numerous environments; see PORTING 49for a list and problems. 50 51This fine freeware file(1) follows the USG (System V) model of the 52file command, rather than the Research (V7) version or the V7-derived 534.[23] Berkeley one. That is, the file /etc/magic contains much of 54the ritual information that is the source of this program's power. 55My version knows a little more magic (including tar archives) than 56System V; the /etc/magic parsing seems to be compatible with the 57(poorly documented) System V /etc/magic format (with one exception; 58see the man page). 59 60In addition, the /etc/magic file is built from a subdirectory 61for easier(?) maintenance. I will act as a clearinghouse for 62magic numbers assigned to all sorts of data files that 63are in reasonable circulation. Send your magic numbers, 64in magic(5) format please, to the maintainer, Christos Zoulas. 65 66COPYING - read this first. 67* `README` - read this second (you are currently reading this file). 68* `INSTALL` - read on how to install 69* `src/apprentice.c` - parses /etc/magic to learn magic 70* `src/apptype.c` - used for OS/2 specific application type magic 71* `src/ascmagic.c` - third & last set of tests, based on hardwired assumptions. 72* `src/asctime_r.c` - replacement for OS's that don't have it. 73* `src/asprintf.c` - replacement for OS's that don't have it. 74* `src/buffer.c` - buffer handling functions. 75* `src/cdf.[ch]` - parser for Microsoft Compound Document Files 76* `src/cdf_time.c` - time converter for CDF. 77* `src/compress.c` - handles decompressing files to look inside. 78* `src/ctime_r.c` - replacement for OS's that don't have it. 79* `src/der.[ch]` - parser for Distinguished Encoding Rules 80* `src/dprintf.c` - replacement for OS's that don't have it. 81* `src/elfclass.h` - common code for elf 32/64. 82* `src/encoding.c` - handles unicode encodings 83* `src/file.c` - the main program 84* `src/file.h` - header file 85* `src/file_opts.h` - list of options 86* `src/fmtcheck.c` - replacement for OS's that don't have it. 87* `src/fsmagic.c` - first set of tests the program runs, based on filesystem info 88* `src/funcs.c` - utilility functions 89* `src/getline.c` - replacement for OS's that don't have it. 90* `src/getopt_long.c` - replacement for OS's that don't have it. 91* `src/gmtime_r.c` - replacement for OS's that don't have it. 92* `src/is_csv.c` - knows about Comma Separated Value file format (RFC 4180). 93* `src/is_json.c` - knows about JavaScript Object Notation format (RFC 8259). 94* `src/is_tar.c, tar.h` - knows about Tape ARchive format (courtesy John Gilmore). 95* `src/localtime_r.c` - replacement for OS's that don't have it. 96* `src/magic.h.in` - source file for magic.h 97* `src/mygetopt.h` - replacement for OS's that don't have it. 98* `src/magic.c` - the libmagic api 99* `src/names.h` - header file for ascmagic.c 100* `src/pread.c` - replacement for OS's that don't have it. 101* `src/print.c` - print results, errors, warnings. 102* `src/readcdf.c` - CDF wrapper. 103* `src/readelf.[ch]` - Stand-alone elf parsing code. 104* `src/softmagic.c` - 2nd set of tests, based on /etc/magic 105* `src/mygetopt.h` - replacement for OS's that don't have it. 106* `src/strcasestr.c` - replacement for OS's that don't have it. 107* `src/strlcat.c` - replacement for OS's that don't have it. 108* `src/strlcpy.c` - replacement for OS's that don't have it. 109* `src/strndup.c` - replacement for OS's that don't have it. 110* `src/tar.h` - tar file definitions 111* `src/vasprintf.c` - for systems that don't have it. 112* `doc/file.man` - man page for the command 113* `doc/magic.man` - man page for the magic file, courtesy Guy Harris. 114 Install as magic.4 on USG and magic.5 on V7 or Berkeley; cf Makefile. 115 116Magdir - directory of /etc/magic pieces 117------------------------------------------------------------------------------ 118 119If you submit a new magic entry please make sure you read the following 120guidelines: 121 122- Initial match is preferably at least 32 bits long, and is a _unique_ match 123- If this is not feasible, use additional check 124- Match of <= 16 bits are not accepted 125- Delay printing string as much as possible, don't print output too early 126- Avoid printf arbitrary byte as string, which can be a source of 127 crash and buffer overflow 128 129- Provide complete information with entry: 130 * One line short summary 131 * Optional long description 132 * File extension, if applicable 133 * Full name and contact method (for discussion when entry has problem) 134 * Further reference, such as documentation of format 135 136gpg for dummies: 137------------------------------------------------------------------------------ 138 139``` 140$ gpg --verify file-X.YY.tar.gz.asc file-X.YY.tar.gz 141gpg: assuming signed data in `file-X.YY.tar.gz' 142gpg: Signature made WWW MMM DD HH:MM:SS YYYY ZZZ using DSA key ID KKKKKKKK 143``` 144 145To download the key: 146 147``` 148$ gpg --keyserver hkp://keys.gnupg.net --recv-keys KKKKKKKK 149``` 150------------------------------------------------------------------------------ 151 152 153Parts of this software were developed at SoftQuad Inc., developers 154of SGML/HTML/XML publishing software, in Toronto, Canada. 155SoftQuad was swallowed up by Corel in 2002 and does not exist any longer. 156