comm compare sorted files and show differences	Command
	SYNOPSIS DESCRIPTION   Options DIAGNOSTICS PORTABILITY SEE ALSO

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SYNOPSIS

comm [-123] file1 file2

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DESCRIPTION

comm locates identical lines within files sorted in the same collating sequence and produces three columns; the first contains lines found only in the first file, the second lines only in the second file and the third lines which are in both files.

Options

-1

suppresses lines that appear only in file1.

-2

suppresses lines that appear only in file2.

-3

suppresses lines that appear both in file1 and file2.

The options suppress individual columns; thus to list only the lines common to both files, use comm -12

To find lines which are unique to one file or the other use comm -3. Note that comm -123 displays nothing.

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DIAGNOSTICS

Possible exit status values are:

0

Successful completion.

1

Failure because of an error opening or reading an input file.

2

Failure which generated a usage message, such as naming only one input file.

Incorrect command line options are reported but do not affect the exit status value.

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PORTABILITY

POSIX.2. x/OPEN Portability Guide 4.0.

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SEE ALSO

Commands:

cmp, diff, sort, uniq