comm (1)

Quick Reference

Select or reject lines common to two files. Both files must be sorted.

  • Produce three tab-separated columns: lines only in first file, lines only in second file and common lines:

comm {{file1}} {{file2}}

  • Print only lines common to both files:

comm -12 {{file1}} {{file2}}

  • Print only lines common to both files, reading one file from stdin:

cat {{file1}} | comm -12 - {{file2}}

  • Get lines only found in first file, saving the result to a third file:

comm -23 {{file1}} {{file2}} > {{file1_only}}

  • Print lines only found in second file, when the files aren't sorted:

comm -13 <(sort {{file1}}) <(sort {{file2}})

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
Note, 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

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

SEE ALSO

join(1), uniq(1)
Full documentation at: <https://www.gnu.org/software/coreutils/comm>
 
or available locally via: info '(coreutils) comm invocation'

Information

Source
Coreutils
OS/version
GNU coreutils 8.29.13-0a854
Source updated
December 2, 2018
Page created
February 9, 2018
Page generated
December 2, 2018