Linux in a Nutshell, Fourth Edition

General RCS Specifications

This section discusses:

• Keyword substitution

• Revision numbering

• Specifying the date

• Specifying states

• Standard options and environment variables

Keyword Substitution

RCS lets you place keyword variables in your working files. These variables are later expanded into revision notes. You can then use the notes either as embedded comments in the input file or as text strings that appear when the output is printed. To create revision notes via keyword substitution, follow this procedure:

1. In your working file, type any of the keywords listed in the next section.

2. Check the file in.

3. Check the file out again. Upon checkout, the co command expands each keyword to include its value. That is, co replaces instances of:

                        $
                        keyword
                        $

   with:

                        $
                        keyword
                        :
                        value
                        $

4. Subsequent checkin and checkout of a file will update any existing keyword values. Unless otherwise noted later, existing values are replaced by new values.

Tip

Many RCS commands have a -k option that provides more flexibility during keyword substitution.

Keywords

$Author$

Username of person who checked in revision.

$Date$

Date and time of checkin.

$Header$

A title that includes the RCS file’s full pathname, revision number, date, author, state, and (if locked) the person who locked the file.

$Id$

Same as $Header: /work/nutshell/qref.linux4/RCS/ch14,v 1.13 2003/05/23 19:00:11 emily Exp emily $, but excludes the full pathname of the RCS file.

$Locker$

Username of person who locked the revision. If the file isn’t locked, this ...