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.\" 32.Dd $Mdocdate: May 31 2007 $ 33.Dt DIFF3 1 34.Os 35.Sh NAME 36.Nm diff3 37.Nd 3-way differential file comparison 38.Sh SYNOPSIS 39.Nm diff3 40.Op Fl 3aEeXx 41.Ar file1 file2 file3 42.Sh DESCRIPTION 43The 44.Nm 45utility compares the contents of three different versions of a file, 46.Ar file1 , 47.Ar file2 48and 49.Ar file3 , 50writing the result to the standard output. 51The options describe different methods of merging and 52purging 53the separate versions into a new file. 54.Nm 55is used by 56.Xr rcs 1 57to merge specific versions or create 58new versions. 59.Pp 60The options are as follows: 61.Bl -tag -width "-E, -X" 62.It Fl 3 63Produces an output script suitable for 64.Xr ed 1 65with changes 66specific only to 67.Ar file3 . 68.It Fl a 69Treat all files as ASCII. 70.It Fl E , X 71Similar to 72.Fl e 73and 74.Fl x , 75respectively, but treat overlapping changes (i.e., changes that would 76be noted with ==== in the normal listing) differently. 77The overlapping lines from both files will be inserted by the edit script, 78bracketed by "<<<<<<" and ">>>>>>" lines. 79.It Fl e 80Produces output in a form suitable as an input script for the 81.Xr ed 1 82utility. 83The script may then be used to merge differences common between all 84three files and differences specific to 85.Ar file1 86and 87.Ar file3 . 88In other words, the 89.Fl e 90option ignores differences specific to 91.Ar file1 92and 93.Ar file2 , 94and those specific to 95.Ar file2 96and 97.Ar file3 . 98It is useful for backing out changes specific to 99.Ar file2 100only. 101.It Fl x 102Produces an output script suitable for 103.Xr ed 1 104with changes 105specific only to all three versions. 106.El 107.Pp 108The 109.Fl E 110option is used by 111.Tn RCS 112.Xr merge 1 113to ensure that overlapping changes in the merged files are preserved 114and brought to someone's attention. 115.Pp 116For example, suppose lines 7-8 are changed in both 117.Ar file1 118and 119.Ar file2 . 120Applying the edit script generated by the command 121.Pp 122.Dl $ diff3 -E file1 file2 file3 123.Pp 124to 125.Ar file1 126results in the file: 127.Bd -literal -offset indent 128lines 1-6 129of file1 130<<<<<<< file1 131lines 7-8 132of file1 133======= 134lines 7-8 135of file3 136>>>>>>> file3 137rest of file1 138.Ed 139.Pp 140The default output of 141.Nm 142makes notation of the differences between all files, and those 143differences specific to each pair of files. 144The changes are described by the commands necessary for 145.Xr ed 1 146to create the desired target from the different versions. 147See 148.Xr diff 1 149for a description of the commands. 150.Bl -tag -width "=====" 151.It Li \&==== 152The lines beneath this notation are ranges of lines which are different 153between all files. 154.It \&==== Ns Va n 155The lines beneath this notation are ranges of lines which are exclusively 156different in file 157.Va n . 158.El 159.Sh ENVIRONMENT 160.Bl -tag -width TMPDIR 161.It Ev TMPDIR 162If the environment variable 163.Ev TMPDIR 164exists, 165.Nm 166will use the directory specified by 167.Ev TMPDIR 168as the temporary directory. 169.El 170.Sh FILES 171.Bl -tag -width /usr/libexec/diff3prog -compact 172.It Pa /tmp/d3a.XXXXXXXXXX 173temporary file 174.It Pa /tmp/d3b.XXXXXXXXXX 175temporary file 176.It Pa /usr/libexec/diff3prog 177the actual executable 178.El 179.Sh SEE ALSO 180.Xr diff 1 , 181.Xr ed 1 , 182.Xr merge 1 , 183.Xr rcs 1 , 184.Xr sdiff 1 185.Sh HISTORY 186A 187.Nm 188command appeared in 189.At v7 . 190.Sh BUGS 191The 192.Fl e 193option cannot catch and change lines which have 194.Ql \&. 195as the first and only character on the line. 196The resulting script will fail on that line 197as 198.Ql \&. 199is an 200.Xr ed 1 201editing command. 202