.\" Copyright (c) 1989 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms are permitted
.\" provided that the above copyright notice and this paragraph are
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.\" by the University of California, Berkeley.  The name of the
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.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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.\"	@(#)comm.1	6.2 (Berkeley) %G%
.\"
.TH COMM 1 ""
.SH NAME
comm - select or reject lines common to two files
.SH SYNOPSIS
\fBcomm [ \fI-123\fP ] [ \fI-\fP ] file1 file2
.SH DESCRIPTION
The
.I comm
utility reads
.I file1
and
.I file2
and produces a three-column output: lines only in
.IR file1 ,
lines only in
.IR file2 ,
and lines in both files.
.PP
The filename ``-'' means the standard input.
.PP
The following options are available:
.TP
-1
Suppress printing of column 1.
.TP
-2
Suppress printing of column 2.
.TP
-3
Suppress printing of column 3.
.PP
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 example, 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.
.PP
.I Comm
assumes that the files are lexically sorted; all characters
participate in line comparisons.
.PP
.I Comm
exits 0 on success, >0 if an error occurred.
.SH "SEE ALSO"
cmp(1), diff(1), sort(1), uniq(1)