Question

I have 4 files sorted alphabetically, A, B, C, and D.
These files contain a single string on each line.
Essentially, what needs to happen is that anything in B gets deleted from A.
The result of that will then be stripped of anything in C.
And similarly, the result of that will be stripped of D.

Is there a way to this using Linux commands?

Answer 1

comm is good for this, either:

cat B C D | sort | comm -2 -3 A -

or:

comm -2 -3 A B | comm -2 -3 - C | comm -2 -3 - D

depending on what’s easier/clearer for your script.