man(1) Manual page archive

     COMM(1)                                                   COMM(1)

          comm - select or reject lines common to two sorted files

          comm [ -123 ] file1 file2

          Comm reads file1 and file2, which should be ordered in ASCII
          collating sequence, and produces a three column output:
          lines only in file1; lines only in file2; and lines in both
          files.  The filename `-' means the standard input.

          Flags 1, 2, or 3 suppress printing of the corresponding col-
          umn.  Thus comm -12 prints only the lines common to the two
          files; comm -23 prints only lines in the first file but not
          in the second; comm -123 is a no-op.

          cmp(1), diff(1), uniq(1)