README revision 169963
1** README for file(1) Command ** 2@(#) $File: README,v 1.34 2006/05/03 18:48:33 christos Exp $ 3 4This is Release 4.x of Ian Darwin's (copyright but distributable) 5file(1) command. This version is the standard "file" command for Linux, 6*BSD, and other systems. (See "patchlevel.h" for the exact release number). 7 8The major feature of 4.x is the refactoring of the code into a library, 9and the re-write of the file command in terms of that library. The library 10itself, libmagic can be used by 3rd party programs that wish to identify 11file types without having to fork() and exec() file. The prime contributor 12for 4.0 was M\xe5ns Rullg\xe5rd. 13 14UNIX is a trademark of UNIX System Laboratories. 15 16The prime contributor to Release 3.8 was Guy Harris, who put in megachanges 17including byte-order independence. 18 19The prime contributor to Release 3.0 was Christos Zoulas, who put 20in hundreds of lines of source code changes, including his own 21ANSIfication of the code (I liked my own ANSIfication better, but 22his (__P()) is the "Berkeley standard" way of doing it, and I wanted UCB 23to include the code...), his HP-like "indirection" (a feature of 24the HP file command, I think), and his mods that finally got the 25uncompress (-z) mode finished and working. 26 27This release has compiled in numerous environments; see PORTING 28for a list and problems. 29 30This fine freeware file(1) follows the USG (System V) model of the file 31command, rather than the Research (V7) version or the V7-derived 4.[23] 32Berkeley one. That is, the file /etc/magic contains much of the ritual 33information that is the source of this program's power. My version 34knows a little more magic (including tar archives) than System V; the 35/etc/magic parsing seems to be compatible with the (poorly documented) 36System V /etc/magic format (with one exception; see the man page). 37 38In addition, the /etc/magic file is built from a subdirectory 39for easier(?) maintenance. I will act as a clearinghouse for 40magic numbers assigned to all sorts of data files that 41are in reasonable circulation. Send your magic numbers, 42in magic(5) format please, to the maintainer, Christos Zoulas. 43 44LEGAL.NOTICE - read this first. 45README - read this second (you are currently reading this file). 46PORTING - read this only if the program won't compile. 47Makefile - read this next, adapt it as needed (particularly 48 the location of the old existing file command and 49 the man page layouts), type "make" to compile, 50 "make try" to try it out against your old version. 51 Expect some diffs, particularly since your original 52 file(1) may not grok the embedded-space ("\ ") in 53 the current magic file, or may even not use the 54 magic file. 55apprentice.c - parses /etc/magic to learn magic 56ascmagic.c - third & last set of tests, based on hardwired assumptions. 57core - not included in distribution due to mailer limitations. 58debug.c - includes -c printout routine 59file.1 - man page for the command 60magic.4 - man page for the magic file, courtesy Guy Harris. 61 Install as magic.4 on USG and magic.5 on V7 or Berkeley; cf Makefile. 62file.c - main program 63file.h - header file 64fsmagic.c - first set of tests the program runs, based on filesystem info 65is_tar.c, tar.h - knows about tarchives (courtesy John Gilmore). 66magdir - directory of /etc/magic pieces 67 magdir/Makefile - ADJUST THIS FOR YOUR CONFIGURATION 68names.h - header file for ascmagic.c 69softmagic.c - 2nd set of tests, based on /etc/magic 70readelf.[ch] - Stand-alone elf parsing code. 71compress.c - on-the-fly decompression. 72print.c - print results, errors, warnings. 73 74If your gzip sometimes fails to decompress things complaining about a short 75file, apply this patch [which is going to be in the next version of gzip]: 76*** - Tue Oct 29 02:06:35 1996 77--- util.c Sun Jul 21 21:51:38 1996 78*** 106,111 **** 79--- 108,114 ---- 80 81 if (insize == 0) { 82 if (eof_ok) return EOF; 83+ flush_window(); 84 read_error(); 85 } 86 bytes_in += (ulg)insize; 87 88E-mail: christos@astron.com 89 90Phone: Do not even think of telephoning me about this program. Send cash first! 91 92Parts of this software were developed at SoftQuad Inc., developers 93of SGML/HTML/XML publishing software, in Toronto, Canada. 94SoftQuad was swallowed up by Corel in 2002 95and does not exist any longer. 96 97From: Kees Zeelenberg 98 99An MS-Windows (Win32) port of File-4.17 is available from 100http://gnuwin32.sourceforge.net/ 101 102File is an implementation of the Unix File(1) command. 103It knows the 'magic number' of several thousands of file types. 104