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comm(1)
NAME
  comm - Compares two sorted files.

SYNOPSIS
  comm [-123] file1 file2

OPTIONS
  -1  Suppresses output of the first column (lines in file1 only).

  -2  Suppresses output of the second column (lines in file2 only).

  -3  Suppresses output of the third column (lines common to file1 and
      file2).

  The command comm -123 produces no output.

DESCRIPTION
  The comm command reads file1 and file2 and writes three columns to standard
  output, showing which lines are common to the files and which are unique to
  each.

  The leftmost column of standard output includes lines that are in file1
  only.	 The middle column includes lines that are in file2 only.  The
  rightmost column includes lines that are in both file1 and file2.

  If you specify a hyphen (-) in place of one of the file names, comm reads
  standard input.

  Generally, file1 and file2 are sorted according to the collating sequence
  specified by the LC_COLLATE environment variable. (See sort(1).)

EXIT STATUS
  0   Successful completion.

  >0  Error occurred.

EXAMPLES
   1.  In the following examples, file1 contains the following sorted list of
       North American cities:


	    Anaheim
	    Baltimore
	    Boston
	    Chicago
	    Cleveland
	    Dallas
	    Detroit
	    Kansas City
	    Milwaukee
	    Minneapolis
	    New York
	    Oakland
	    Seattle
	    Toronto

       The second file, file2, contains this sorted list:


	    Atlanta
	    Chicago
	    Cincinnati
	    Houston
	    Los Angeles
	    Montreal
	    New York
	    Philadelphia
	    Pittsburgh
	    San Diego
	    San Francisco
	    St. Louis

       To display the lines unique to each file and common to the two files,
       enter:
	    comm file1 file2

       This command results in the following output:
	    Anaheim
		    Atlanta
	    Baltimore
	    Boston
			    Chicago
		    Cincinnati
	    Cleveland
	    Dallas
	    Detroit
		    Houston
	    Kansas City
		    Los Angeles
	    Milwaukee
	    Minneapolis
		    Montreal
			    New York
	    Oakland
		    Philadelphia
		    Pittsburgh
		    San Diego
		    San Francisco
	    Seattle
		    St. Louis
	    Toronto

       The leftmost column contains lines in file1 only, the middle column
       contains lines in file2 only, and the rightmost column contains lines
       common to both files.

   2.  To display any one or two of the three output columns, include the
       appropriate flags to suppress the columns you do not want.  For
       example, the following command displays columns 1 and 2 only:
	    comm -3 file1 file2

	    Anaheim
		   Atlanta
	    Baltimore
	    Boston
		   Cincinnati
	    Cleveland
	    Dallas
	    Detroit
		   Houston
	    Kansas City
		   Los Angeles
	    Milwaukee
	    Minneapolis
		   Montreal
	    Oakland
		   Philadelphia
		   Pittsburgh
		   San Diego
		   San Francisco
	    Seattle
		   St. Louis
	    Toronto

       The following command displays output from only the second column:
	    comm -13 file1 file2

	    Atlanta
	    Cincinnati
	    Houston
	    Los Angeles
	    Montreal
	    Philadelphia
	    Pittsburgh
	    San Diego
	    San Francisco
	    St. Louis

       The following command displays output from only the third column:
	    comm -12 file1 file2

	    Chicago
	    New York



SEE ALSO
  Commands:  cmp(1), diff(1), sdiff(1), sort(1), uniq(1)