Content-type: text/html Man page of comm

comm

Section: User Commands (1)
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NAME

comm - Compares two sorted files.  

SYNOPSIS

comm [-123] file1 file2


 

OPTIONS

Suppresses output of the first column (lines in file1 only). Suppresses output of the second column (lines in file2 only). 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

Successful completion. Error occurred.
 

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 contains 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


 

SEE ALSO

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


 

Index

NAME
SYNOPSIS
OPTIONS
DESCRIPTION
EXIT STATUS
EXAMPLES
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 02:43:00 GMT, October 02, 2010