comm command line utility

comm -- select or reject lines common to two files

The comm utility reads file1 and file2, which should be sorted lexically, and produces three text columns as output: lines only in file1; lines only in file2; and lines in both files.

The filename - means the standard input.

comm [OPTION] FILE1 FILE2

options:

• -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)

Example

$ cat e_1.txt 
AAA
BBB
CCC
$ cat e_2.txt 
AAA
CCC
EEE
$ comm e_1.txt e_2.txt 
		AAA
BBB
		CCC
	EEE
$ comm -12 e_1.txt e_2.txt 
AAA
CCC