1.\" $OpenBSD: diff3.1,v 1.4 2004/07/07 14:28:23 jaredy 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 April 18, 1994 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 aexEX3 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 a 63Treat all files as ASCII. 64.It Fl e 65Produces output in a form suitable as an input script for the 66.Xr ed 1 67utility. 68The script may then be used to merge differences common between all 69three files and differences specific to 70.Ar file1 71and 72.Ar file3 . 73In other words, the 74.Fl e 75option ignores differences specific to 76.Ar file1 77and 78.Ar file2 , 79and those specific to 80.Ar file2 81and 82.Ar file3 . 83It is useful for backing out changes specific to 84.Ar file2 85only. 86.It Fl x 87Produces an output script suitable for 88.Xr ed 1 89with changes 90specific only to all three versions. 91.It Fl 3 92Produces an output script suitable for 93.Xr ed 1 94with changes 95specific only to 96.Ar file3 . 97.It Fl E , X 98Similar to 99.Fl e 100and 101.Fl x , 102respectively, but treat overlapping changes (i.e., changes that would 103be noted with ==== in the normal listing) differently. 104The overlapping lines from both files will be inserted by the edit script, 105bracketed by "<<<<<<" and ">>>>>>" lines. 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.Sh HISTORY 185A 186.Nm 187command appeared in 188.At v7 . 189.Sh BUGS 190The 191.Fl e 192option cannot catch and change lines which have 193.Ql \&. 194as the first and only character on the line. 195The resulting script will fail on that line 196as 197.Ql \&. 198is an 199.Xr ed 1 200editing command. 201