magic(4)						     Kernel Interfaces Manual							  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
       continuation 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 decimal, 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  extensions:
	      You  use the backslash () to escape an unprintable character.  The string can contain all special character such as 
, , 
, and
	      f. If a backslash appears in the string, it must be escaped with a second backslash (\).  You  can  use  octal	representation	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 
 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 ^#!{ }*\%[^ 
]*\%	%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   ^1h[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)