comm Linux Command compare two sorted files line by line and write to output, It requires two sorted files which it compares line by line.

Syntax

comm [OPTION]... FILE1 FILE2

Options

Option	Description
-1	suppress printing of the first column (lines unique to the first file)
-2	suppress printing of the second column (lines unique to the second file)
-3	suppress printing of the third column (lines common to both the files)
–-check-order	check's the input is correctly sorted, even if all the input lines are pairable
–-nocheck-order	do not check that the input is correctly sorted
–-output-delimiter=STR	separate columns with string STR

Example

$cat >file1.txt
one
two
three

$cat >file2.txt
one
three
four

$comm file1.txt file2.txt
		one
	three
	four
two
three