COMM(1)				 User Commands			       COMM(1)

NAME
       comm - compare two sorted files line by line

SYNOPSIS
       comm [OPTION]... FILE1 FILE2

DESCRIPTION
       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
       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
       Written by Richard M. Stallman and David MacKenzie.

REPORTING BUGS
       Report bugs to: bug-coreutils@gnu.org
       GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
       General help using GNU software: <https://www.gnu.org/gethelp/>
       Report any translation bugs to <https://translationproject.org/team/>

COPYRIGHT
       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
       join(1), uniq(1)

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

GNU coreutils 9.8		September 2025			       COMM(1)