comm(1) — Linux manual page

COMM(1)                       User Commands                       COMM(1)

NAME         top

       comm - compare two sorted files line by line

SYNOPSIS         top

       comm [OPTION]... FILE1 FILE2

DESCRIPTION         top

       Compare sorted files FILE1 and FILE2 line by line.

       When FILE1 or FILE2 (not both) is -, read standard input.

       With no options, produce three-column output.  Column one contains
       lines unique to FILE1, column two contains lines unique to FILE2,
       and column three contains lines common to both files.

       -1     suppress column 1 (lines unique to FILE1)

       -2     suppress column 2 (lines unique to FILE2)

       -3     suppress column 3 (lines that appear in both files)

       --check-order
              check that the input is correctly sorted, even if all input
              lines are pairable

       --nocheck-order
              do not check that the input is correctly sorted

       --output-delimiter=STR
              separate columns with STR

       --total
              output a summary

       -z, --zero-terminated
              line delimiter is NUL, not newline

       --help display this help and exit

       --version
              output version information and exit

       Comparisons honor the rules specified by 'LC_COLLATE'.

EXAMPLES         top

       comm -12 file1 file2
              Print only lines present in both file1 and file2.

       comm -3 file1 file2
              Print lines in file1 not in file2, and vice versa.

AUTHOR         top

       Written by Richard M. Stallman and David MacKenzie.

REPORTING BUGS         top

       GNU coreutils online help:
       <https://www.gnu.org/software/coreutils/>
       Report any translation bugs to
       <https://translationproject.org/team/>

COPYRIGHT         top

       Copyright © 2025 Free Software Foundation, Inc.  License GPLv3+:
       GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

SEE ALSO         top

       join(1), uniq(1)

       Full documentation <https://www.gnu.org/software/coreutils/comm>
       or available locally via: info '(coreutils) comm invocation'

COLOPHON         top

       This page is part of the coreutils (basic file, shell and text
       manipulation utilities) project.  Information about the project
       can be found at ⟨http://www.gnu.org/software/coreutils/⟩.  If you
       have a bug report for this manual page, see
       ⟨http://www.gnu.org/software/coreutils/⟩.  This page was obtained
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       send a mail to man-pages@man7.org

GNU coreutils 9.7               April 2025                        COMM(1)

Pages that refer to this page: join(1),  uniq(1)

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