What Is A Magic Number? - IBM

Problem

What is a magic number?

Resolving The Problem

QUESTION: What is a magic number? ANSWER: A magic number is a numeric or string constant that indicates the file type. This number is in the first 512 bytes of the file. By default the localized magic file /usr/lib/locale/locale/LC_MESSAGES/magic is used to identify files that have a magic number. If a localized magic file does not exist, the /etc/magic file is utilized. From the command line a user can do the following command, "File script", which will result in the output, "script: executable shell script". Appended below is the contents of the file /etc/magic. #ident "@(#)magic 1.36 98/03/03 SMI" /* SVr4.0 1.30 */ # file cmd's magic file # # # Basically, the fields of this file are as follows: # byte offset, value type, optional operator (= by default), value # to match (numeric or string), and string to be printed. Numeric # values may be decimal, octal, or hex. Also note that the last # string may have 1 printf format spec. # The '>' in occassional column 1's is magic: it forces file to # continue scanning and matching additional lines. The first line # afterwards not so marked terminates the search. # # # The entry for ELF is not needed anymore, as file now uses the elf(3e) # routines to look at ELF files. It remains here, commented out, in case # someone really needs it. #0 string \177ELF ELF #>4 byte 1 32-bit #>5 byte 1 LSB #>5 byte 2 MSB #>16 short 0 unknown type #>16 short 1 relocatable #>16 short 2 executable #>16 short 3 dynamic lib #>16 short 4 core file #>18 short 0 unknown machine #>18 short 1 WE32100 #>18 short 2 SPARC #>18 short 3 80386 #>18 short 4 M68000 #>18 short 5 M88000 #>18 short 6 i80486 #>18 short 7 i860 #>18 short 8 RS3000_BE #>18 short 9 UNKNOWN #>18 short 10 RS3000_LE #>18 short 11 RS6000 #>18 short 12 UNKNOWN #>18 short 13 UNKNOWN #>18 short 14 UNKNOWN #>18 short 15 PA_RISC #>18 short 16 nCUBE #>18 short 17 VPP500 #>18 short 18 SPARC32PLUS #>18 short 19 UNKNOWN #>18 short 20 PowerPC #>20 long 1 Version 1 #>36 long 1 MAU Required 257 string ustar USTAR tar archive >156 byte 88 extended format 0 short 070701 cpio archive 0 string 070701 ASCII cpio archive 0 short 070702 cpio archive - CRC header 0 string 070702 ASCII cpio archive - CRC header 0 short 070707 cpio archive - CHR (-c) header 0 string 070707 ASCII cpio archive - CHR (-c) header 0 long 0177555 obsolete ar archive 0 short 0177545 pdp11/pre System V ar archive 0 long 0100554 apl workspace 0 short 017037 packed data 0 string <ar> System V Release 1 ar archive 0 string !<arch> current ar archive 0 short 0407 pdp11/pre System V vax executable >8 short >0 not stripped >15 byte >0 - version %ld 0 short 0401 unix-rt ldp 0 short 0405 pdp11 overlay 0 short 0410 pdp11/pre System V vax pure executable >8 short >0 not stripped >15 byte >0 - version %ld 0 short 0411 pdp11 separate I&D >8 short >0 not stripped >15 byte >0 - version %ld 0 short 015001 Compiled Terminfo Entry 0 short 0433 Curses screen image 0 short 0434 Curses screen image 0 short 0437 pdp11 kernel overlay 0 short 0570 vax executable >12 long >0 not stripped >22 short >0 - version %ld 0 short 0575 vax pure executable >12 long >0 not stripped >22 short >0 - version %ld 0 short 0502 basic-16 executable >12 long >0 not stripped >22 short >0 - version %ld 0 short 0503 basic-16 executable (TV) >12 long >0 not stripped >22 short >0 - version %ld 0 short 0510 x86 executable >12 long >0 not stripped 0 short 0511 x86 executable (TV) >12 long >0 not stripped 0 short 0550 3b20 executable >12 long >0 not stripped >22 short >0 - version %ld 0 short 0551 3b20 executable (TV) >12 long >0 not stripped >22 short >0 - version %ld 0 short 0560 WE32000 executable >12 long >0 not stripped >18 short ^00010000 - N/A on 3b2/300 w/paging >18 short &00020000 - 32100 required >18 short &00040000 and mau hardware required >20 short 0443 (target shared library) >20 short 0410 (swapped) >20 short 0413 (paged) >22 short >0 - version %ld 0 short 0561 WE32000 executable (TV) >12 long >0 not stripped >18 short &00020000 - 32100 required >18 short &00040000 and mau hardware required >22 short >0 - version %ld 0 short =0512 iAPX 286 executable small model (COFF) >12 long >0 not stripped >22 short >0 - version %ld 0 short =0522 iAPX 286 executable large model (COFF) >12 long >0 not stripped >22 short >0 - version %ld 0 short 0514 iAPX 386 executable (COFF) (deprecated) >12 long >0 not stripped >22 short >0 - version %ld 0 short 0520 mc68k executable >12 long >0 not stripped 0 short 0521 mc68k executable (shared) >12 long >0 not stripped 0 short 0522 mc68k executable (shared demand paged) >12 long >0 not stripped 2 short 0410 pure >1 byte 0 sun2 executable >1 byte 1 mc68010 executable >1 byte 2 mc68020 executable >1 byte 3 SPARC executable >0 byte >077 dynamically linked 2 short 0407 impure >1 byte 0 sun2 executable >1 byte 1 mc68010 executable >1 byte 2 mc68020 executable >1 byte 3 SPARC executable >0 byte >077 dynamically linked 2 short 0413 Sun demand paged >1 byte 0 sun2 executable >1 byte 1 mc68010 executable >1 byte 2 mc68020 executable >1 byte 3 SPARC executable >0 byte >077 dynamically linked 0 short 0x8001 Adobe PostScript Type 1 binary font (PFB) 0 long 0x00010000 TrueType font file version 1.0 (TTF) 0 byte 0x80 8086 relocatable (Microsoft) 0 byte 0xf0 MS-DOS library 0 short 0xff65 x.out >2 string __.SYMDEF randomized >0 byte x archive 0 short 0x206 Microsoft a.out >0x1e short &0x10 overlay >0x1e short &0x2 separate >0x1e short &0x4 pure >0x1e short &0x800 segmented >0x1e short &0x400 standalone >0x1e short &0x8 fixed-stack >0x1c byte &0x80 byte-swapped >0x1c byte &0x40 word-swapped >0x10 long >0 not-stripped >0x1e short ^0xc000 pre-SysV >0x1c byte &0x4 86 >0x1c byte &0x9 286 >0x1c byte &0xa 386 >0x1e short &0x1 executable >0x1e short ^0x1 object file >0x1e short &0x40 Large Text >0x1e short &0x20 Large Data >0x1e short &0x120 Huge Objects Enabled 0 short 0x10b VAX demand load format a.out object file >0x10 long >0 not stripped 0 short 0x140 old Microsoft 8086 x.out >0x3 byte &0x4 separate >0x3 byte &0x2 pure >0 byte &0x1 executable >0 byte ^0x1 relocatable >0x14 long >0 not stripped 0 long 0x10b VAX demand load format a.out object file >0x10 long >0 not stripped 0 long 0x140 old Microsoft 8086 x.out >0x3 byte &0x4 separate >0x3 byte &0x2 pure >0 byte &0x1 executable >0 byte ^0x1 relocatable >0x14 long >0 not stripped 0 long 0xe807 object file (z8000 a.out) 0 long 0xe808 pure object file (z8000 a.out) 0 long 0xe809 separate object file (z8000 a.out) 0 long 0xe805 overlay object file (z8000 a.out) 0 long 0x178 Bell 5.0 executable 2 short 0410 Sun read-only text executable >2 short 0407 Sun old executable >1 char 3 (SPARC) >1 char 2 (68020) >1 char 1 (68010) >1 char 0 (Sun2) # The following are from SunOS 4.1 0 short 0143561 byte-swapped cpio archive 0 long 0101555 PDP-11 single precision APL workspace 0 long 0101554 PDP-11 double precision APL workspace 0 long 0101557 VAX single precision APL workspace 0 long 0101556 VAX double precision APL workspace 0 short 017437 old packed data 0 string \037\036 packed data 0 string \377\037 compacted data 0 string \037\235 compressed data >2 byte&0x80 >0 block compressed >2 byte&0x1f x %d bits 0 string \037\213 gzip compressed data >2 byte 8 - deflate method >3 byte &0x1 , ascii >3 byte &0x2 , continuation >3 byte &0x4 , extra field >3 byte &0x8 , original file name >3 byte &0x10 , comment >3 byte &0x20 , encrypted >8 byte 2 , max compression >8 byte 4 , max speed 0 string !<arch>\n__.SYMDEF archive random library 0 long 0x1010101 MMDF mailbox 0 string <!OPS Interleaf ASCII document 24 string SunGKS SunGKS # version number follows, in the form m.n >0 string GKSM Metafile 0 string GKSM GKS Metafile # version number follows, in the form <!OPS, Version n.n> 0 string %!PS-AdobeFont Adobe PostScript ASCII font (PFA) 0 string %! PostScript document # version ID follows, in the form PS-Adobe-nn 0 string Interpress/Xerox Interpress document

# version ID follows, in the form /n.n 0 string StartFontMetrics Adobe font metrics 0 string StartFont Adobe font bits 0 long 0x137A2944 NeWS bitmap font 0 long 0x137A2947 NeWS font family 8 long 0x137A2B45 X11/NeWS bitmap font 8 long 0x137A2B48 X11/NeWS font family 0 string snoop Snoop capture file >8 long >0 - version %ld 0 short 0436 vfont definition 0 string <MakerFile Frame Maker document 0 string <MIFFile Frame Maker MIF file 0 string <MML Frame Maker MML file 0 string .snd audio data: >12 long 1 8-bit u-law, >12 long 2 8-bit linear PCM, >12 long 3 16-bit linear PCM, >12 long 4 24-bit linear PCM, >12 long 5 32-bit linear PCM, >12 long 6 32-bit floating point, >12 long 7 64-bit floating point, >12 long 23 compressed (4-bit G.721 ADPCM), >12 long 24 compressed (8-bit G.722 ADPCM), >12 long 25 compressed (3-bit G.723 ADPCM), >12 long 26 compressed (5-bit G.723 ADPCM), >12 long 27 8-bit A-law, >20 long 1 mono, >20 long 2 stereo, >20 long 4 quad, >16 long x %d Hz 0 short 0x1010 PEX Binary Archive 0 long 0x59a66a95 rasterfile, >4 long >0 %ld x >8 long >0 %ld x >12 long >0 %ld >20 long 0 old format image >20 long 1 standard format image >20 long 2 run-length byte encoded image >20 long 3 XRGB or RGB format image >20 long 4 tiff format image >20 long 5 iff (TAAC format) image >20 long 0xffff experimental format image 0 long 0x884f5053 Interleaf fast-saved document 0 long 0x2a535441 Aster*x >7 long 0x574f5244 Words Document >7 long 0x47524150 Graphic >7 long 0x53505245 Spreadsheet >7 long 0x4d414352 Macro 0 long 0x32323738 Aster*x Version 2 >29 byte 0x36 Words Document >29 byte 0x35 Graphic >29 byte 0x32 Spreadsheet >29 byte 0x38 Macro 4 string pgscriptver IslandWrite document 13 string DrawFile IslandDraw document 0 string P1 PBM ascii file 0 string P2 PGM ascii file 0 string P3 PPM ascii file 0 string P4 PBM raw file 0 string P5 PGM raw file 0 string P6 PPM raw file 0 string \115\115 TIFF file, big-endian 0 string \111\111 TIFF file, little-endian 0 string GIF87a GIF file, v87 0 string GIF89a GIF file, v89 0 string \377\330\377\340 JPEG file 0 string \377\330\377\356 JPG file 8 string ILBM IFF ILBM file 0 string \312\376\272\276 java class file # Magic number to identify profiles related to the Kodak ColorManagement # System. (KCMS). KCMS uses the ICC format identified by "acsp" at byte 36. 36 string acsp Kodak Color Management System, ICC Profile 0 string %PDF-1.0 Adobe Portable Document Format (PDF) v1.0 0 string %PDF-1.1 Adobe Portable Document Format (PDF) v1.1 0 string %PDF-1.2 Adobe Portable Document Format (PDF) v1.2 0 string PK\003\004 ZIP archive 0 string MZ DOS executable (EXE) 0 string LZ DOS built-in 0 byte 0xe9 DOS executable (COM) 0 byte 0xeb DOS executable (COM)

[{"Product":{"code":"SSSHVH","label":"Rational TestManager"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":"Manual Test","Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"2002.05.00.305.000","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]

Historical Number

17496