comm(1)comm(1)NAMEcomm - select or reject lines common to two sorted files
SYNOPSIS
file1 file2
DESCRIPTIONcomm reads file1 and file2, which should be ordered in increasing col‐
lating sequence (see sort(1) and Environment Variables below), and pro‐
duces a three-column output:
Column 1: Lines that appear only in file1,
Column 2: Lines that appear only in file2,
Column 3: Lines that appear in both files.
If is used for file1 or file2, the standard input is used.
Options 1, 2, or 3 suppress printing of the corresponding column. Thus
prints only the lines common to the two files; prints only lines in the
first file but not in the second; does nothing useful.
EXTERNAL INFLUENCES
Environment Variables
determines the collating sequence expects from the input files.
determines the language in which messages are displayed.
If is not specified in the environment or is set to the empty string,
the value of determines the language in which messages are displayed.
If is not specified in the environment or is set to the empty string,
the value of is used as a default. If is not specified or is set to
the empty string, a default of ``C'' (see lang(5)) is used instead of
If any internationalization variable contains an invalid setting,
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 and have been ordered in the collat‐
ing sequence defined by the or environment variable.
Print all lines common to and (in other words, print column 3):
Print all lines that appear in but not in (in other words, print column
1):
Print all lines that appear in but not in (in other words, print column
2):
SEE ALSOcmp(1), diff(1), sdiff(1), sort(1), uniq(1).
STANDARDS CONFORMANCEcomm(1)
