|HP-UX Reference > C
HP-UX 11i Version 3: February 2007
comm — select or reject lines common to two sorted files
comm reads file1 and file2, which should be ordered in increasing collating sequence (see sort(1) and Environment Variables below), and produces a three-column output:
If - is used for file1 or file2, the standard input is used.
Options 1, 2, or 3 suppress printing of the corresponding column. 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 does nothing useful.
LC_COLLATE determines the collating sequence comm expects from the input files.
LC_MESSAGES determines the language in which messages are displayed.
If LC_MESSAGES is not specified 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 specified in the environment or is set to the empty string, the value of LANG is used as a default. If LANG is not specified 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).
The following examples assume that file1 and file2 have been ordered in the collating sequence defined 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