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| Chapter 2 UNIX Commands |

## comm

    comm [options] file1 file2

Compare lines common to the sorted files `file1` and `file2`. Three-column output is produced: lines unique to `file1`, lines unique to `file2`, and lines common to both `files`. comm is similar to diff in that both commands compare two files. But comm can also be used like uniq; that is, comm selects duplicate or unique lines between `two` sorted files, whereas uniq selects duplicate or unique lines within the `same` sorted file.

### Options

-

  Read the standard input.

-1

  Suppress printing of column 1.

-2

  Suppress printing of column 2.

-3

  Suppress printing of column 3.

-12

  Print only lines in column 3 (lines common to `file1` and `file2`).

-13

  Print only lines in column 2 (lines unique to `file2`).

-23

  Print only lines in column 1 (lines unique to `file1`).

### Example

Compare two lists of top-ten movies, and display items that appear in both lists:

>     comm -12 siskel_top10 ebert_top10

Reference: comb |  | Reference: compress