Linux Pocket Guide

Name

comm [options] file1 file2 — coreutils

Synopsis

/usr/bin stdin stdout - file -- opt --help --version

The comm command compares two sorted files and produces three columns of output, separated by tabs:

1. All lines that appear in file1 but not in file2.

2. All lines that appear in file2 but not in file1.

3. All lines that appear in both files.

For example, if file1 and file2 contain these lines:

file1:    file2:
apple    baker
baker    charlie
charlie    dark

then comm produces this output:

$ comm file1 file2
apple
    baker
    charlie
  dark

Useful options
-1	Suppress column 1.
-2	Suppress column 2.
-3	Suppress column 3.