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| Chapter 18 |

# 18. The RCS Utility

Contents:
Overview of Commands
Basic Operation
General RCS Specifications
Conversion Guide for SCCS Users
Alphabetical Summary of Commands

This section presents the following topics:

- Overview of commands

- Basic operation

- General RCS specifications

- Conversion guide for SCCS users

- Alphabetical summary of commands

As with SCCS in the preceding section, the Revision Control System (RCS) is designed to keep track of multiple file revisions, thereby reducing the amount of storage space needed. With RCS you can automatically store and retrieve revisions, merge or compare revisions, keep a complete history (or log) of changes, and identify revisions using symbolic keywords. RCS is believed to be more efficient than SCCS. RCS is not part of standard SVR4 but can be obtained from the Free Software Foundation in Cambridge, Mass. This section describes Version 5.6, although we note important differences in versions 4 and 5.

## 18.1 Overview of Commands

The three most important RCS commands are:

ci

  Check in revisions (put a file under RCS control).

co

  Check out revisions.

rcs

  Set up or change attributes of RCS files.

Two commands provide information about RCS files:

ident

  Extract keyword values from an RCS file.

rlog

  Display a summary (log) about the revisions in an RCS file.

You can compare RCS files with these commands:

merge

  Incorporate changes from two files into a third file.

rcsdiff

  Report differences between revisions.

rcsmerge

  Incorporate changes from two RCS files into a third RCS file.

The following commands help with configuration management. However, they are considered optional, so they are not always installed.

rcsclean

  Remove working files that have not been changed.

rcsfreeze

  Label the files that make up a configuration.

17.6 sccs and Pseudo-commands |  | 18.2 Basic Operation