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AIX Version 4.3 Commands Reference, Volume 1

comm Command

Purpose

Selects or rejects lines common to two sorted files.

Syntax

comm [ -1 -2 -3 ] File1 File2

Description

Note: If you specify - (minus) for one of the file names, the comm command reads standard input.

The comm command reads the File1 and File2 parameters and writes, by default, a three-column output to standard output. The columns consist of:

Both File1 and File2 should be sorted according to the collating sequence specified by the current National Language environment.

Flags

-1 Suppresses the display of the first column (lines in File1).
-2 Suppresses the display of the second column (lines in File2).
-3 Suppresses the display of the third column (lines common to File1 and File2).

Exit Status

This command returns the following exit values:

0 All input files were output successfully.
>0 An error occurred.

Examples

  1. To display the lines unique to each file and common to both, enter:
    comm things.to.do things.done
    If the files things.to.do and things.done contain the following lists:
    things.to.do
     
    buy soap
    groceries
    luncheon
    meeting at 3
    system update
    tech. review
     
    things.done
     
    2nd revision
    interview
    luncheon
    system update
    tech. review
    weekly report
    then the comm command displays:
           2nd revision
    buy soap
    groceries
           interview
                   luncheon
    meeting at 3
                   system update
                   tech. review
           weekly report
    The first column contains the lines found only in things.to.do . The second column, indented with a tab character, lists the lines found only in things.done . The third column, indented with two tabs, lists the lines common to both.
  2. To display the lines that appear in only one file, enter:
    comm -23 things.to.do things.done
    This suppresses the second and third columns of the comm command listing. If the files are the same as in Example 1, then the following is displayed:
    buy soap
    groceries
    meeting at 3

File

/usr/bin/comm Contains the comm command.

Related Information

The cmp command, diff command, sdiff command, sort command, uniq command.

The environment file.

Understanding Locale in AIX Version 4.3 System Management Guide: Operating System and Devices.

National Language Support Overview for Programming in AIX General Programming Concepts: Writing and Debugging Programs.


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