1.\" $OpenBSD: diff3.1,v 1.7 2007/05/31 19:20:09 jmc Exp $ 2.\" 3.\" Copyright (c) 1990, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)diff3.1 8.2 (Berkeley) 4/18/94 31.\" $FreeBSD$ 32.\" 33.Dd May 25, 2017 34.Dt DIFF3 1 35.Os 36.Sh NAME 37.Nm diff3 38.Nd 3-way differential file comparison 39.Sh SYNOPSIS 40.Nm diff3 41.Op Fl 3aEeiXx 42.Op Fl Fl diff-program Ar program 43.Op Fl Fl strip-trailing-cr 44.Op Fl L | Fl Fl label Ar label1 45.Op Fl L | Fl Fl label Ar label2 46.Op Fl L | Fl Fl label Ar label3 47.Ar file1 file2 file3 48.Sh DESCRIPTION 49The 50.Nm 51utility compares the contents of three different versions of a file, 52.Ar file1 , 53.Ar file2 54and 55.Ar file3 , 56writing the result to the standard output. 57The options describe different methods of merging and 58purging 59the separate versions into a new file. 60.Nm 61is used by 62.Xr rcs 1 63to merge specific versions or create 64new versions. 65.Pp 66The options are as follows: 67.Bl -tag -width "-E, -X" 68.It Fl 3 , Fl Fl easy-only 69Produces an output script suitable for 70.Xr ed 1 71with changes 72specific only to 73.Ar file3 . 74.It Fl a , Fl Fl text 75Treat all files as ASCII. 76.It Fl E , Fl Fl show-overlap 77.It Fl X 78Similar to 79.Fl e 80and 81.Fl x , 82respectively, but treat overlapping changes (i.e., changes that would 83be noted with ==== in the normal listing) differently. 84The overlapping lines from both files will be inserted by the edit script, 85bracketed by "<<<<<<" and ">>>>>>" lines. 86.It Fl e , Fl Fl ed 87Produces output in a form suitable as an input script for the 88.Xr ed 1 89utility. 90The script may then be used to merge differences common between all 91three files and differences specific to 92.Ar file1 93and 94.Ar file3 . 95In other words, the 96.Fl e 97option ignores differences specific to 98.Ar file1 99and 100.Ar file2 , 101and those specific to 102.Ar file2 103and 104.Ar file3 . 105It is useful for backing out changes specific to 106.Ar file2 107only. 108.It Fl i 109Appends 'w' and 'q' 110.Xr ed 1 111commands. 112.It Fl L , Fl Fl label 113Defines labels to print instead of file names 114.Ar file1 , 115.Ar file2 116and 117.Ar file3 . 118.It Fl x, Fl Fl overlap-only 119Produces an output script suitable for 120.Xr ed 1 121with changes 122specific only to all three versions. 123.It Fl Fl diff-program Ar program 124Use 125.Ar program 126instead of the default 127.Xr diff 1 128to compare files. 129.It Fl Fl strip-trailing-cr 130Strip trailing carriage return on input files. 131.El 132.Pp 133The 134.Fl E 135option is used by 136.Tn RCS 137.Xr merge 1 138to ensure that overlapping changes in the merged files are preserved 139and brought to someone's attention. 140.Pp 141For example, suppose lines 7-8 are changed in both 142.Ar file1 143and 144.Ar file2 . 145Applying the edit script generated by the command 146.Pp 147.Dl $ diff3 -E file1 file2 file3 148.Pp 149to 150.Ar file1 151results in the file: 152.Bd -literal -offset indent 153lines 1-6 154of file1 155<<<<<<< file1 156lines 7-8 157of file1 158======= 159lines 7-8 160of file3 161>>>>>>> file3 162rest of file1 163.Ed 164.Pp 165The default output of 166.Nm 167makes notation of the differences between all files, and those 168differences specific to each pair of files. 169The changes are described by the commands necessary for 170.Xr ed 1 171to create the desired target from the different versions. 172See 173.Xr diff 1 174for a description of the commands. 175.Bl -tag -width "=====" 176.It Li \&==== 177The lines beneath this notation are ranges of lines which are different 178between all files. 179.It \&==== Ns Va n 180The lines beneath this notation are ranges of lines which are exclusively 181different in file 182.Va n . 183.El 184.Sh SEE ALSO 185.Xr diff 1 , 186.Xr ed 1 , 187.Xr merge 1 , 188.Xr rcs 1 , 189.Xr sdiff 1 190.Sh HISTORY 191A 192.Nm 193command appeared in 194.At v7 . 195.Sh BUGS 196The 197.Fl e 198option cannot catch and change lines which have 199.Ql \&. 200as the first and only character on the line. 201The resulting script will fail on that line 202as 203.Ql \&. 204is an 205.Xr ed 1 206editing command. 207