Question

What will be the command if we want to suppress column 1 and column 2 in the output of comm Command?

(a) comm  -12

(b) comm -1-2

(c) comm -3

(d) comm -1,-2

I had been asked this question in unit test.

This question is from Comparing Files:comm, cmp and diff Command topic in section Handling Ordinary Files of Unix

Answer 1

Right answer is (a) comm  -12

Easy explanation: comm command provides us with an option for suppressing the columns in the output. For this task, we have to provide the column number as an option in the comm command. For example, -1 for column 1, -2 for column 2 and -3 for column 3.