comm

Reference

Find unique and shared lines between two files

Category

Linux Command

Usage

comm [OPTION]... FILE1 FILE2

Manual

Files FILE1 and FILE2 must be sorted.

With no options, produce three-column output. Column one contains lines unique to FILE1, column two contains lines unique to FILE2, and column three contains lines common to both files.

Options

  • -1: suppress column 1 (lines unique to FILE1)
  • -2: suppress column 2 (lines unique to FILE2)
  • -3: suppress column 3 (lines that appear in both files)
  • --check-order: check that the input is correctly sorted, even if all input lines are pairable
  • --nocheck-order: do not check that the input is correctly sorted
  • --output-delimiter=STR: separate columns with STR
  • --help: display this help and exit
  • --version: output version information and exit

Note, comparisons honor the rules specified by "LC_COLLATE".

Examples

Find lines only in FILE1 by setting -2 and -3:

comm -23 FILE1 FILE2

Find lines only in FILE2 by setting -1 and -3:

comm -13 FILE1 FILE2

Find lines common to both files by setting -1 and -2:

comm -12 FILE1 FILE2

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