COMM(1) BSD General Commands Manual COMM(1)NAMEcomm — select or reject lines common to two files
SYNOPSIScomm [-123i] file1 file2
The comm utility reads file1 and file2, which should be sorted lexically,
and produces three text columns as output: lines only in file1; lines
only in file2; and lines in both files.
The filename ``-'' means the standard input.
The following options are available:
-1 Suppress printing of column 1.
-2 Suppress printing of column 2.
-3 Suppress printing of column 3.
-i Case insensitive comparison of lines.
Each column will have a number of tab characters prepended to it equal to
the number of lower numbered columns that are being printed. For exam‐
ple, if column number two is being suppressed, lines printed in column
number one will not have any tabs preceding them, and lines printed in
column number three will have one.
The comm utility assumes that the files are lexically sorted; all charac‐
ters participate in line comparisons.
The LANG, LC_ALL, LC_COLLATE, and LC_CTYPE environment variables affect
the execution of comm as described in environ(7).
The comm utility exits 0 on success, and >0 if an error occurs.
SEE ALSOcmp(1), diff(1), sort(1), uniq(1)STANDARDS
The comm utility conforms to IEEE Std 1003.2-1992 (“POSIX.2”).
The -i option is an extension to the POSIX standard.
A comm command appeared in Version 4 AT&T UNIX.
BSD December 12, 2009 BSD