1.de Id
2.ds Rv \\$3
3.ds Dt \\$4
4..
5.Id $Id: merge.1,v 5.3 1991/02/28 19:18:45 eggert Exp $
6.TH MERGE 1 \*(Dt GNU
7.SH NAME
8merge \- three-way file merge
9.SH SYNOPSIS
10.B merge
11[
12.B \-L
13.I label1
14[
15.B \-L
16.I label3
17] ] [
18.B \-p
19] [
20.B \-q
21]
22.I "file1 file2 file3"
23.SH DESCRIPTION
24.B merge
25incorporates all changes that lead from
26.I file2
27to
28.I file3
29into
30.IR file1 .
31The result goes to standard output if
32.B \-p
33is present, into
34.I file1
35otherwise.
36.B merge
37is useful for combining separate changes to an original. Suppose
38.I file2
39is the original, and both
40.I file1
41and
42.I file3
43are modifications of
44.IR file2 .
45Then
46.B merge
47combines both changes.
48.PP
49An overlap occurs if both
50.I file1
51and
52.I file3
53have changes in a common segment of lines.
54On a few older hosts where
55.B diff3
56does not support the
57.B \-E
58option,
59.B merge
60does not detect overlaps, and merely supplies the changed lines from
61.I file3.
62On most hosts, if overlaps occur,
63.B merge
64outputs a message (unless the
65.B \-q
66option is given),
67and includes both alternatives
68in the result. The alternatives are delimited as follows:
69.LP
70.RS
71.nf
72.BI <<<<<<< " file1"
73.I "lines in file1"
74.B "======="
75.I "lines in file3"
76.BI >>>>>>> " file3"
77.RE
78.fi
79.LP
80If there are overlaps, the user should edit the result and delete one of the
81alternatives.
82If the
83.BI \-L "\ label1"
84and
85.BI \-L "\ label3"
86options are given, the labels are output in place of the names
87.I file1
88and
89.I file3
90in overlap reports.
91.SH DIAGNOSTICS
92Exit status is 0 for no overlaps, 1 for some overlaps, 2 for trouble.
93.SH IDENTIFICATION
94Author: Walter F. Tichy.
95.br
96Revision Number: \*(Rv; Release Date: \*(Dt.
97.br
98Copyright \(co 1982, 1988, 1989 by Walter F. Tichy.
99.br
100Copyright \(co 1990, 1991 by Paul Eggert.
101.SH SEE ALSO
102diff3(1), diff(1), rcsmerge(1), co(1).