COMM(1)                    OpenBSD Reference Manual                    COMM(1)

NAME
     comm - select or reject lines common to two files



SYNOPSIS
     comm [-123f] file1 file2

DESCRIPTION
     The comm utility reads file1 and file2, which should be sorted lexically,
     and produces three text columns as output: lines only in file1; lines on-
     ly 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.

     -f      Fold case in line comparisons.

     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.

     comm assumes that the files are lexically sorted; all characters partici-
     pate in line comparisons.

DIAGNOSTICS
     The comm utility exits 0 on success or >0 if an error occurred.

SEE ALSO
     cmp(1),  diff(1),  sort(1),  uniq(1)

STANDARDS
     The comm utility conforms to IEEE Std1003.2-1992 (``POSIX.2'').

OpenBSD 2.6                      June 6, 1993                                1