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magic(4)							      magic(4)

NAME
       magic - Magic file for the file command

SYNOPSIS
       /etc/magic

DESCRIPTION
       The  magic file is used by the file command to identify files that have
       some sort of magic number.  A magic number is  any  numeric  or	string
       constant that identifies the file containing the constant.

       The format for the magic file is as follows:

	    offset   type   operator,value   string

       The  fields should be separated by tabs.	 Each record must be contained
       on one line.

       The fields contain the following data: This field contains  the	number
       of  bytes  from	the beginning of the file on which you are running the
       file command to the first byte of the magic number of character	string
       you want to identify.  Use a right angle bracket (>) to indicate a con‐
       tinuation line that  supplies  additional  information  describing  the
       file.  This field contains information about the data type of the magic
       number or character string at the specified byte	 offset.   Valid  data
       types  for  this field are: Unsigned character type Unsigned short type
       Long type Character (byte) string This field contains instructions  for
       the  file  command on how to compare the value read from the file being
       checked with the value stored in the Value  Type	 field	of  the	 magic
       file.   The  valid  comparison operators are: The two values are equal.
       The value in the file being checked is greater than the	value  in  the
       magic file.  The value in the file being checked is less than the value
       in the magic file.  All the bits in the magic file value must be set in
       the value from the file being checked.

	      Note  that the Comparison Operator field is optional.  If you do
	      not specify the operator, the values are expected to  be	equal.
	      This  field contains the value used to compare what is read from
	      the file being checked by the file command.  You can  use	 deci‐
	      mal, hex, or octal numbers in this field or character strings in
	      the form of regular expressions.

	      Precede all hex numbers with the	characters  zero  and  x  (for
	      example,	0x80).	To  specify an octal number, precede it with a
	      zero (for example, 0200).	 Decimal numbers  require  no  special
	      representation  and  should be written as integers (for example,
	      128).

	      The rules for specifying character strings follow those  of  the
	      ed  editor  (see ed(1)) for regular expressions, with two exten‐
	      sions: You use the backslash (\) to escape an unprintable	 char‐
	      acter.  The string can contain all special character such as \n,
	      \b, \r, and \f. If a backslash appears in the string, it must be
	      escaped  with a second backslash (\\).  You can use octal repre‐
	      sentation to specify any byte value other than zero  (0).	  Text
	      found  in the file can be inserted into the printed string if it
	      is preceded and followed by  \\%	delimiters.   All  text	 found
	      between these delimiters is displayed as the print string.

	      This regular expression search never terminates until a match is
	      explicitly found or rejected.  The special  character  \n	 is  a
	      valid  character	in  the	 patterns.   Therefore, the pattern .*
	      should never be used here.  This field contains  the  string  to
	      print.  The  string  provides  information  about	 the file. The
	      string can include text found in the file when requested with an
	      appropriate printf() format.

EXAMPLES
       The  following  is  an example of a script: string ^#!{ }*\\%[^ \n]*\\%
       %s

       The following are examples of executable images:	 >2	   short    02
       POSIX  >2       short   01		      SVID >16	    long    >0
       not stripped

       The following are examples of  text  and	 data  files:  0	string
       ^\01h[0-9][0-9][0-9][0-9][0-9]	  sccsfile  0	     string   ^#ifndef
       c program 0	 string	 ^070707			   ASCII  cpio
       archive

FILES
       /etc/magic

RELATED INFORMATION
       Commands:  file(1) delim off

								      magic(4)
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