comm [-123] file1 file2
The file name indicated by a hyphen - means the standard input.
Each column will have a number of tab characters prepended to it equal to the number of lower numbered columns that are being printed. For example, if column number two is being suppressed, lines printed in column number one will not have any tabs preceding them, and lines printed in column number three will have one.
The comm(1) utility assumes that the files are lexically sorted; all characters participate in line comparisons.