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cmp(1)								       cmp(1)



NAME

  cmp -	Compares two files

SYNOPSIS

  cmp [-l  | -s] file1 file2

STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  cmp:XCU5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

OPTIONS

  -l  Prints the byte number (decimal) and the differing bytes (octal) for
      each difference.

  -s  Does not print data for differing	files; returns only an exit value.

OPERANDS

  file1
      The path name of a file to be compared.

  file2
      The path name of a file to be compared.

DESCRIPTION

  The cmp command compares two files.

  If file1 or file2 is - (dash), standard input	is used	for that file.	It is
  an error to specify -	for both files.

  By default, the cmp command prints no	information if the files are the
  same.	 If the	files differ, cmp prints the byte and line number where	the
  difference occurred.

  The cmp command also specifies whether one file is an	initial	subsequence
  of the other (that is, if the	cmp command reads an End-of-File character in
  one file before finding any differences).  Usually, you use the cmp command
  to compare nontext files and the diff	command	to compare text	files.

  Note that bytes and lines reported by	cmp are	numbered from 1.




EXIT STATUS

  The following	exit values are	returned:

  0   The files	are identical.

  1   The files	differ.	 This includes files of	different lengths that are
      identical	in the first part of both files.

  >>1  An error occurred.

EXAMPLES

   1.  To determine whether two	files are identical, enter:
	    cmp	prog.o.bak prog.o

       The preceding command compares the files	prog.o.bak and prog.o.	If
       the files are identical,	a message is not displayed. If the files
       differ, the location of the first difference is displayed.  For
       instance:
	    prog.o.bak prog.o differ:  byte 5, line 1

       If the message cmp: EOF on prog.o.bak is	displayed, then	the first
       part of prog.o is identical to prog.o.bak, but there is additional
       data in prog.o.

       If the message cmp: EOF on prog.o is displayed, it is prog.o.bak	that
       is the same as prog.o but also contains addition	data.

   2.  To display each pair of bytes that differ, enter:
	    cmp	-l prog.o.bak prog.o

       This compares the files and then	displays the byte number (in decimal)
       and the differing bytes (in octal) for each difference.	For example,
       if the fifth byte is octal 101 in prog.o.bak and	141 in prog.o, then
       the cmp command displays:
	    5 101 141
	     .
	     .
	     .



ENVIRONMENT VARIABLES

  The following	environment variables affect the execution of cmp:

  LANG
      Provides a default value for the internationalization variables that
      are unset	or null. If LANG is unset or null, the corresponding value
      from the default locale is used.	If any of the internationalization
      variables	contain	an invalid setting, the	utility	behaves	as if none of
      the variables had	been defined.

  LC_ALL
      If set to	a non-empty string value, overrides the	values of all the
      other internationalization variables.

  LC_CTYPE
      Determines the locale for	the interpretation of sequences	of bytes of
      text data	as characters (for example, single-byte	as opposed to multi-
      byte characters in arguments).

  LC_MESSAGES
      Determines the locale for	the format and contents	of diagnostic
      messages written to standard error.

  NLSPATH
      Determines the location of message catalogues for	the processing of
      LC_MESSAGES.


SEE ALSO

  Commands:  comm(1), bdiff(1),	diff(1), diff3(1), sdiff(1)

  Standards:  standards(5)