rcsmerge - merge RCS revisions
rcsmerge incorporates the changes between two revisions of an RCS file
  into the corresponding working file.
Pathnames matching an RCS suffix denote RCS files; all others
    denote working files. Names are paired as explained in ci(1).
At least one revision must be specified with one of the options
    described below, usually -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.
rcsmerge prints a warning if there are overlaps, and
    delimits the overlapping regions as explained in merge(1). The
    command is useful for incorporating changes into a checked-out revision.
  - -A
- Output conflicts using the -A style of diff3(1), if
      supported by diff3. This merges all changes leading from
      file2 to file3 into file1, and generates the most
      verbose output.
- -E, -e
- These options specify conflict styles that generate less information than
      -A. See diff3(1) for details. The default is -E. With
      -e, rcsmerge does not warn about conflicts.
- -ksubst
- Use subst style keyword substitution. See co(1) for details.
      For example, -kk -r1.1 -r1.2 ignores differences in
      keyword values when merging the changes from 1.1 to 1.2. It
      normally does not make sense to merge binary files as if they were text,
      so rcsmerge refuses to merge files if -kb expansion is
    used.
- -p[rev]
- Send the result to standard output instead of overwriting the working
      file.
- -q[rev]
- Run quietly; do not print diagnostics.
- -r[rev]
- Merge with respect to revision rev. Here an empty rev stands
      for the latest revision on the default branch, normally the head.
- -T
- This option has no effect; it is present for compatibility with other RCS
      commands.
- -V
- Print RCS's version number.
- -Vn
- Emulate RCS version n. See co(1) for details.
- -xsuffixes
- Use suffixes to characterize RCS files. See ci(1) for
      details.
- -zzone
- Use zone as the time zone for keyword substitution. See
      co(1) for details.
Suppose you have released revision 2.8 of 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 rcsmerge -p -r2.8 -r3.4 f.c >f.merged.c
Then examine f.merged.c. Alternatively, if you want to save
    the updates to 2.8 in the RCS file, check them in as revision 2.8.1.1 and
    execute co -j:
 ci -r2.8.1.1 f.c
  
   co -r3.4 -j2.8:2.8.1.1 f.c
As another example, the following command undoes the changes
    between revision 2.4 and 2.8 in your currently checked out revision in
    f.c.
 rcsmerge -r2.8 -r2.4 f.c
Note the order of the arguments, and that f.c will be
    overwritten.
  - RCSINIT
- options prepended to the argument list, separated by spaces. See
      ci(1) for details.
Exit status is 0 for no overlaps, 1 for some overlaps, 2 for trouble.
Author: Walter F. Tichy.
Manual Page Revision: 5.6; Release Date: 1995/06/01.
Copyright © 1982, 1988, 1989 Walter F. Tichy.
Copyright © 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert.
ci(1), co(1), ident(1), merge(1), rcs(1), rcsdiff(1), rcsintro(1), rlog(1),
  rcsfile(5)
Walter F. Tichy, RCS--A System for Version Control, Software--Practice &
  Experience 15, 7 (July 1985), 637-654.