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Using RCS

This short tutorial shows you how to use of RCS to keep track of changes in configuration files. To get RCS and its related tools, install rcs.

Note: Similarities between CVS and RCS will cause any $Header: /var/www/www.gentoo.org/raw_cvs/gentoo/xml/htdocs/news/en/gwn/20040216-newsletter.xml,v 1.1 2004/02/17 01:53:48 carlos Exp $ or $Id: 20040216-newsletter.xml,v 1.1 2004/02/17 01:53:48 carlos Exp $ tags to be rewritten when you put files under revision control.

Code Listing 1: Adding files to RCS

# cd /etc
# mkdir RCS

// Put make.conf under revision control
# ci -i make.conf
RCS/make.conf,v  <--  make.conf
enter description, terminated with single '.' or end of file:
NOTE: This is NOT the log message!
>> make.conf - custom settings for portage
>> .
initial revision: 1.1
done
   // The file is now in RCS, so put it back in /etc for reading
# co make.conf

Notice that make.conf is now under revision control and is read-only. To edit the file, you need to perform the following steps:



Code Listing 2: Editing a file under revision control

// Checkout the file with locking enabled
# co -l make.conf
RCS/make.conf,v  -->  make.conf
revision 1.1 (locked)
done

// Edit the file
# ${EDITOR} make.conf

// Check the file back in and unlock it.
# ci -u make.conf
RCS/make.conf,v  <--  make.conf
new revision: 1.2; previous revision: 1.1
enter log message, terminated with single '.' or end of file:
>> changed DISTDIR to use a drive with more space
>> .  done

This can be a tedious process so it's better to put all the commands in a script to do it automatically.



Code Listing 3: Example script for revision control

#!/bin/sh
# Script to edit files under revision control
[ [ -f "RCS/$1,v" ]] && co -l $1
${EDITOR} $1
[ [ -f "RCS/$1,v" ]] && ci -u $1

For more information on using RCS see man 1 rcsintro.

From http://www.gentoo.org/news/en/gwn/20040216-newsletter.xml

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