HP UX Operating Systems 133

comm(1)

NAME

comm - select or reject lines common to two sorted ®les

SYNOPSIS

comm [-[123] ] ®le1 ®le2

DESCRIPTION

comm reads ®le1 and ®le2, which should be ordered in increasing collating sequence (see sort(1) and Environment Variables below), and produces a three-column output:

Column 1: Lines that appear only in ®le1,

Column 2: Lines that appear only in ®le2,

Column 3: Lines that appear in both ®les.

If - is used for ®le1 or ®le2, the standard input is used.

Options 1, 2, or 3 suppress printing of the corresponding column. Thus comm -12prints only the lines common to the two ®les; comm -23prints only lines in the ®rst ®le but not in the second; comm -123does nothing useful.

EXTERNAL INFLUENCES

Environment Variables

LC_COLLATE determines the collating sequence comm expects from the input ®les.

LC_MESSAGES determines the language in which messages are displayed.

If LC_MESSAGES is not speci®ed in the environment or is set to the empty string, the value of LANG determines the language in which messages are displayed. If LC_COLLATE is not speci®ed in the environment or is set to the empty string, the value of LANG is used as a default. If LANG is not speci®ed or is set to the empty string, a default of ``C'' (see lang(5)) is used instead of LANG. If any internationalization variable contains an invalid setting, comm behaves as if all internationalization variables are set to ``C''. See environ(5).

International Code Set Support

Single- and multi-byte character code sets are supported.

EXAMPLES

The following examples assume that file1 and file2 have been ordered in the collating sequence de®ned by the LC_COLLATE or LANG environment variable.

Print all lines common to file1 and file2 (in other words, print column 3):

comm -12 file1 file2

Print all lines that appear in file1 but not in file2 (in other words, print column 1):

comm -23 file1 file2

Print all lines that appear in file2 but not in file1 (in other words, print column 2):

comm -13 file1 file2