1.\" Copyright (c) 1989, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" From: @(#)comm.1 8.1 (Berkeley) 6/6/93 36.\" $FreeBSD: src/usr.bin/comm/comm.1,v 1.4.2.5 2002/07/11 00:43:37 tjr Exp $ 37.\" $DragonFly: src/usr.bin/comm/comm.1,v 1.2 2003/06/17 04:29:25 dillon Exp $ 38.\" 39.Dd June 6, 1993 40.Os 41.Dt COMM 1 42.Sh NAME 43.Nm comm 44.Nd select or reject lines common to two files 45.Sh SYNOPSIS 46.Nm 47.Op Fl 123i 48.Ar file1 file2 49.Sh DESCRIPTION 50The 51.Nm 52utility reads 53.Ar file1 54and 55.Ar file2 , 56which should be 57sorted lexically, and produces three text 58columns as output: lines only in 59.Ar file1 ; 60lines only in 61.Ar file2 ; 62and lines in both files. 63.Pp 64The filename ``-'' means the standard input. 65.Pp 66The following options are available: 67.Bl -tag -width indent 68.It Fl 1 69Suppress printing of column 1. 70.It Fl 2 71Suppress printing of column 2. 72.It Fl 3 73Suppress printing of column 3. 74.It Fl i 75Case insensitive comparison of lines. 76.El 77.Pp 78Each column will have a number of tab characters prepended to it 79equal to the number of lower numbered columns that are being printed. 80For example, if column number two is being suppressed, lines printed 81in column number one will not have any tabs preceding them, and lines 82printed in column number three will have one. 83.Pp 84The 85.Nm 86utility assumes that the files are lexically sorted; all characters 87participate in line comparisons. 88.Sh EXIT STATUS 89.Ex -std 90.Sh SEE ALSO 91.Xr cmp 1 , 92.Xr diff 1 , 93.Xr sort 1 , 94.Xr uniq 1 95.Sh STANDARDS 96The 97.Nm 98utility conforms to 99.St -p1003.2-92 . 100.Sh HISTORY 101A 102.Nm 103command appeared in 104.At v4 . 105