Revision Control System
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| Original author(s) | Walter F. Tichy |
|---|---|
| Developer(s) | GNU Project |
| Initial release | 1982 |
| Stable release | 5.9.4 (January 22, 2015[1]) [±] |
| Written in | C |
| Operating system | Unix-like |
| Type | Revision control |
| License | GNU General Public License |
| Website | www |
The Revision Control System (RCS) is a software implementation of revision control that automates the storing, retrieval, logging, identification, and merging of revisions. RCS is useful for text that is revised frequently, for example programs, documentation, procedural graphics, papers, and form letters. RCS is also capable of handling binary files, though with reduced efficiency. Revisions are stored with the aid of the diff utility.
Contents
Development
RCS was first released in 1982[2] [3] by Walter F. Tichy while he was at Purdue University. RCS was an alternative to the then-popular Source Code Control System (SCCS). It is currently maintained by the GNU Project.[4]
Licensing
Initially (through version 3, which was distributed in 4.3BSD), its license prohibited redistribution without written permission from Walter Tichy:[5]
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Copyright (C) 1982 by Walter F. Tichy [...] All rights reserved. No part of this software may be sold or distributed in any form or by any means without the prior written permission of the author.
A READ_ME file accompanied some versions of RCS which further restricted distribution, e.g., in 4.3BSD-Reno.[6][better source needed]
Ca. 1989, the RCS license was altered to something similar to the contemporary BSD licenses, as seen by comments in the source code.[7][better source needed]
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Redistribution and use in source and binary forms are permitted provided that the above copyright notice and this paragraph are duplicated in all such forms and that any documentation, advertising materials, and other materials related to such distribution and use acknowledge that the software was developed by Walter Tichy.
RCS 4.3, released July 26, 1990, was distributed "under license by the Free Software Foundation", under the terms of the GPL.[8][full citation needed]
Mode of operation
RCS operates only on single files; it has no way of working with an entire project, so it does not support atomic commits affecting multiple files. Although it provides branching for individual files, the version syntax is cumbersome. Instead of using branches, many teams just use the built-in locking mechanism and work on a single head branch.[citation needed]
Successors
Concurrent Versions System (CVS)
A simple system called CVS was developed, capable of dealing with RCS files en masse, and this was the next natural step of evolution of this concept, as it “transcends but includes” elements of its predecessor. CVS was originally a set of scripts which used RCS programs to manage the files. It no longer does that; rather, it operates directly on the files.
Project Revision Control System (PRCS)
A later, higher-level system, PRCS[9] uses RCS-like files, but was never simply a wrapper. In contrast to CVS, PRCS improves the delta compression of the RCS files using Xdelta.
Advantages
In single-user scenarios, such as server configuration files or automation scripts, RCS may still be the preferred revision control tool as it is simple and no central repository needs to be accessible for it to save revisions. This makes it a more reliable tool when the system is in dire maintenance conditions. Additionally, the saved backup files are easily visible to the administration so the operation is straightforward. However, there are no built-in tamper protection mechanisms (that is, users who can use the RCS tools to version a file also, by design, are able to directly manipulate the corresponding version control file) and this is leading some security conscious administrators to consider client/server version control systems that restrict users' ability to alter the version control files.[citation needed]
Application
Some wiki engines, including TWiki and Foswiki, use RCS for storing page revisions.
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ RCS 4.3 README file.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- Notes
- Walter F. Tichy: RCS--A System for Version Control. In: Software—Practice and Experience. July 1985. Volume 15. Number 7. Pages 637-654. References to the paper at CiteSeer
Further reading
- Don Bolinger, Tan Bronson, Applying RCS and SCCS - From Source Control to Project Control. O'Reilly, 1995.
External links
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- Original RCS at Purdue
- : RCS file management program – OpenBSD General Commands Manual
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