comm(1)								      comm(1)



NAME
  comm - Compares two sorted files.

SYNOPSIS

  comm [-123] file1 file2

FLAGS

  -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 right-
  most column includes lines that are in both file1 and file2.

  If you specify a hyphen (-) in place of one of the filenames, 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).)

EXAMPLES

  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 con-
  tains lines in file2 only, and the rightmost column contains lines common
  to both files.

  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

EXIT VALUES

  0	    Successful completion

  >0	    Error occurred

RELATED INFORMATION

  Commands:  cmp(1), diff(1), sdiff(1), sort(1), uniq(1).