Mac OS X Tiger in a Nutshell

Name

comm

Synopsis

comm [options] file1 file2

Compares 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. In addition, comm can 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. A filename of - means standard input, not an option.

Options

-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 10 movies and display items that appear in both lists:

$ comm -12 shalit_top10 maltin_top10