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  Robert Kiesling
  v1.4, 14 August 1997

  This document covers basic installation and usage of RCS, the GNU
  Revision Control System, under Linux.  It also covers the installation
  of the diff(1) and diff3(1) utilities, which are necessary for RCS to
  operate.  This document may be reproduced freely, in whole or in part,
  provided that any usage of this document conforms to the general copy´┐Ż
  right notice of the HOWTO series of the Linux Documentation Project.
  See the file COPYRIGHT for details.  Send all complaints, suggestions,
  errata, and any miscellany to, so I can keep
  this document as complete and up to date as possible.

  Table of Contents

  1. Overview of RCS.

  2. System requirements.

  3. Compiling RCS from Source.

  4. Creating and maintaining archives.

  ci(1) and co(1).
  6. Revision histories.

  7. Including RCS data in working files.

  8. RCS and
  emacs(1) Version Control.


  1.  Overview of RCS.

  RCS, the revision control system, is a suite of programs that tracks
  changes in text files and controls shared access to files in work
  group situations.  It is generally used to maintain source code
  modules.  It lends itself to tracking revisions of document files as

  RCS was written by Walter F. Tichy and Paul Eggert.  The latest
  version which has been ported to Linux is RCS Version 5.7.  There is
  also a semi-official, threaded version available.  Much of the
  information in this HOWTO is taken from the RCS man pages.

  RCS includes the rcs(1) program, which controls RCS archive file
  attributes, ci(1) and co(1), which check files in and out of RCS
  archives, ident(1), which searches RCS archives by keyword
  identifiers, rcsclean(1), a program to clean up files that are not
  being worked on or haven't changed, rcsdiff(1), which runs diff(1) to
  compare the revisions, rcsmerge(1), which merges two RCS branches into
  a single working file, and rlog(1), which prints RCS log messages.

  Files archived by RCS may be text of any format, or binary if the diff
  program used to generate change files handles 8-bit data.  Files may
  optionally include identification strings to aid in tracking by
  ident(1).  RCS uses the utilities diff(1) and diff3(3) to generate the
  change files between revisions.  A RCS archive consists of the initial
  revision of a file, which is version 1.1, and a series of change
  files, one for each revision.  Each time a file is checked out of an
  archive with co(1), edited, and checked back into the archive with
  ci(1), the version number is increased, for example, to 1.2, 1.3, 1.4,
  and so on for successive revisions.

  The archives themselves commonly reside in a ./RCS subdirectory,
  although RCS has other options for archive storage.

  For an overview of RCS, see the rcsintro(1) manual page.

  2.  System requirements.

  RCS needs diff(1) and diff3(3) to generate the context diff files
  between revisions.  The diff utilities suite needs to be installed on
  your system, and when you install RCS, the software will check for its

  Precompiled diffutils binaries are available at:

  and its mirror sites.  If you need to compile diff(1), et al., from
  source, it is located at:

  and its mirror sites.

  You will also need to have the ELF libraries installed on your system
  if you want to install pre-built binaries.  See the ELF-HOWTO for
  further details.

  3.  Compiling RCS from Source.

  Get the source distribution of RCS Version 5.7.  It is available at

  and its mirrors. After you have unpacked the archive into your source
  tree, you need to configure RCS for your system.  This is done via the
  configure script in the source directory, which you need to execute
  first.  This will generate a Makefile and the appropriate for
  your system.  You can then type

  make install

  which will build the binaries.  At some point you may need to su to
  root so the binaries can be installed in the correct directories.

  4.  Creating and maintaining archives.

  The program rcs(1) does the work or creating archives and modifying
  their attributes.  A summary of rcs(1) options may be found in the
  rcs(1) manual page.

  The easiest way to create an archive is first to mkdir RCS in the
  current directory, then initialize the archive with the
  rcs -i name_of_work_file

  command.  This creates and archive with the name
  ./RCS/name_of_work_file,v and requests a text message describing the
  archive, but it does not deposit any revisions in the archive.  You
  can turn on or off strict archive locking with the commands

  rcs -L name_of_work_file


  rcs -U name_of_work_file

  respectively.  There are other options for controlling access to the
  archive, setting its format, and setting revision numbers, which are
  covered in the rcs(1) manual page.

  5.  ci(1)  and co(1) .

  ci(1) and co(1) are the commands used to check files in and out of
  their RCS archives.  The ci(1) command may also be used to a check a
  file both in and out of an archive.  In their simplest forms, ci(1)
  and co(1) take only the name of the working file.

  ci name_of_work_file


  co name_of_work_file

  The command form

  ci -l name_of_work_file

  checks in the file with locking enabled, and

  co -l name_of_work_file

  is performed automatically. That is, ci -l checks the file out again
  with locking enabled.

  ci -u name_of_work_file

  checks the file into the archive, and checks it out again with locking
  disabled.  In all cases, the user is prompted for a log message.

  ci(1) will also create a RCS archive if one does not exist already.

  If you don't specify a revision, ci(1) increments the version number
  of the last revision locked in the archive, and appends the revised
  working file to it.  If you specify a revision on an existing branch,
  it must be higher than the existing revision numbers.  ci(1) will also
  create a new branch if you specify the revision of a branch which does
  not exist.  See the ci(1) and co(1) man pages for details.

  ci(1) and co(1) have various options for interactive and non-
  interactive use.  Again, see the ci(1) and co(1) man pages for

  6.  Revision histories.

  The rlog(1) program provides information about the archive file and
  the logs of each revision stored in it.  A command like

  rlog work_file_name

  will print the version history of the file, each revision's creation
  date and userids of author and the person who locked the file.  You
  can specify archive attributes and revision parameters to view.

  7.  Including RCS data in working files.

  co(1) maintains a list of keywords of the RCS database which are
  expanded when the working file is checked out.  The keyword $Id$ in a
  document will expand to a string which contains the file name,
  revision number, the date checked out, the author, the revision
  status, and the locker, if any.  Including the keyword $Log$ will
  expand to the document's revision history log.

  These and other keywords may be used as search criteria of the RCS
  archive.  See the ident(1) man page for further details.

  8.  RCS and emacs(1)  Version Control.

  The Version Control facility of emacs(1) works as a front end to RCS.
  This information applies specifically to Version 19.34 of GNU Emacs,
  which is provided with the major Linux distributions.  When editing a
  file with emacs(1) which is registered with RCS, the command vc-
  toggle-read-only (bound to C-x C-q by default) will check a file in to
  the emacs's Version Control, and then into RCS.  Emacs will open a
  buffer where you can type a log message to be included in the RCS log.
  When you are finished typing a log entry, type C-c C-c to terminate
  your input and proceed with the check-in process.

  If you have selected strict locking for the file with RCS, you must
  re-lock the file for editing by emacs(1).  You can check the file out
  for emacs's Version Control with the command % in buffer-menu mode.

  For more information, see the GNU Emacs Manual and the Emacs info

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