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.TH RCSMERGE 1 "\*(Dt" "GNU RCS \*(Rv"
.SH NAME
rcsmerge \- merge RCS revisions
.SH SYNOPSIS
.B rcsmerge
.RI [ options ] " file"
.SH DESCRIPTION
.B rcsmerge
incorporates the changes between two revisions
of an \*o into the corresponding working file.
.PP
Filenames matching an \*r suffix denote \*os;
all others denote working files.
Names are paired as explained in
.BR ci (1).
.PP
At least one revision must be specified with one of the options
described below, usually
.BR \-r .
At most two revisions may be specified.
If only one revision is specified, the latest
revision on the default branch (normally the highest branch on the trunk)
is assumed for the second revision.
Revisions may be specified numerically or symbolically.
.PP
.B rcsmerge
prints a warning if there are overlaps, and delimits
the overlapping regions as explained in
.BR merge (1).
The command is useful for incorporating changes into a checked-out revision.
.SH OPTIONS
.TP
.B \-A
Output conflicts using the
.B \-A
style of
.BR diff3 (1),
if supported by
.BR diff3 .
This merges all changes leading from
.I file2
to
.I file3
into
.IR file1 ,
and generates the most verbose output.
.TP
\f3\-E\fP, \f3\-e\fP
These options specify conflict styles that generate less information
than
.BR \-A .
See
.BR diff3 (1)
for details.
The default is
.BR \-E .
With
.BR \-e ,
.B rcsmerge
does not warn about conflicts.
.TP
.BI \-k subst
Use
.I subst
style keyword substitution.
See
.BR co (1)
for details.
For example,
.B "\-kk\ \-r1.1\ \-r1.2"
ignores differences in keyword values when merging the changes from
.B 1.1
to
.BR 1.2 .
It normally does not make sense to merge binary files as if they were text, so
.B rcsmerge
refuses to merge files if
.B \-kb
expansion is used.
.TP
.BR \-p [\f2rev\fP]
Send the result to standard output instead of overwriting the working file.
.TP
.BR \-q [\f2rev\fP]
Run quietly; do not print diagnostics.
.TP
.BR \-r [\f2rev\fP]
Merge with respect to revision
.IR rev .
Here an empty
.I rev
stands for the latest revision on the default branch, normally the head.
.TP
.B \-T
This option has no effect;
it is present for compatibility with other \*r commands.
.TP
.BI \-V
Print \*r's version number.
.TP
.BI \-V n
Emulate \*r version
.IR n .
See
.BR co (1)
for details.
.TP
.BI \-x "suffixes"
Use
.I suffixes
to characterize \*os.
See
.BR ci (1)
for details.
.TP
.BI \-z zone
Use
.I zone
as the time zone for keyword substitution.
See
.BR co (1)
for details.
.SH EXAMPLES
Suppose you have released revision 2.8 of
.BR f.c .
Assume
furthermore that after you complete an unreleased revision 3.4, you receive
updates to release 2.8 from someone else.
To combine the updates to 2.8 and your changes between 2.8 and 3.4,
put the updates to 2.8 into file f.c and execute
.LP
.B "    rcsmerge  \-p  \-r2.8  \-r3.4  f.c  >f.merged.c"
.PP
Then examine
.BR f.merged.c .
Alternatively, if you want to save the updates to 2.8 in the \*o,
check them in as revision 2.8.1.1 and execute
.BR "co \-j":
.LP
.B "    ci  \-r2.8.1.1  f.c"
.br
.B "    co  \-r3.4  \-j2.8:2.8.1.1  f.c"
.PP
As another example, the following command undoes the changes
between revision 2.4 and 2.8 in your currently checked out revision
in
.BR f.c .
.LP
.B "    rcsmerge  \-r2.8  \-r2.4  f.c"
.PP
Note the order of the arguments, and that
.B f.c
will be
overwritten.
.SH ENVIRONMENT
.TP
.B \s-1RCSINIT\s0
Options prepended to the argument list, separated by spaces.
A backslash escapes spaces within an option.
The
.B \s-1RCSINIT\s0
options are prepended to the argument lists of most \*r commands.
Useful
.B \s-1RCSINIT\s0
options include
.BR \-q ,
.BR \-V ,
.BR \-x ,
and
.BR \-z .
.TP
.B \s-1RCS_MEM_LIMIT\s0
Normally, for speed, commands either memory map or copy into memory
the \*o if its size is less than the
.IR memory-limit ,
currently defaulting to ``unlimited''.
Otherwise (or if the initially-tried speedy ways fail),
the commands fall back to using
standard i/o routines.
You can adjust the memory limit by setting
.B \s-1RCS_MEM_LIMIT\s0
to a numeric value
.IR lim
(measured in kilobytes).
An empty value is silently ignored.
As a side effect, specifying
.B \s-1RCS_MEM_LIMIT\s0
inhibits fall-back to slower routines.
.TP
.B \s-1TMPDIR\s0
Name of the temporary directory.
If not set, the environment variables
.B \s-1TMP\s0
and
.B \s-1TEMP\s0
are inspected instead and the first value found is taken;
if none of them are set,
a host-dependent default is used, typically
.BR /tmp .
.SH DIAGNOSTICS
Exit status is 0 for no overlaps, 1 for some overlaps, 2 for trouble.
.ds EY 1990, 1991, 1992, 1993, 1994, 1995
.SH IDENTIFICATION
Author: Walter F. Tichy.
.br
Manual Page Revision: \*(Rv; Release Date: \*(Dt.
.br
Copyright \(co 2010-2020 Thien-Thi Nguyen.
.br
Copyright \(co \*(EY Paul Eggert.
.br
Copyright \(co 1982, 1988, 1989 Walter F. Tichy.
.br
.SH "SEE ALSO"
.BR ci (1),
.BR co (1),
.BR ident (1),
.BR merge (1),
.BR rcs (1),
.BR rcsdiff (1),
.BR rlog (1),
.BR rcsfile (5).
.PP
Walter F. Tichy,
\*r\*-A System for Version Control,
.I "Software\*-Practice & Experience"
.BR 15 ,
7 (July 1985), 637-654.
.PP
The full documentation for \*r is maintained as a Texinfo manual.
If the
.BR info (1)
and \*r programs are properly installed at your site, the command
.IP
.B info rcs
.PP
should give you access to the complete manual.
Additionally, the \*r homepage:
.IP
.B http://www.gnu.org/software/rcs/
.PP
has news and links to the latest release, development site, etc.