phpman > man > COMM(1)

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⚡ TLDR: COMM (tldr-pages)

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}})

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

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 any translation bugs to <https://translationproject.org/team/>

COPYRIGHT
Copyright © 2020 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.