With the initial check-in (see section on check-in) of a file, RCS requests a file description. The request is not for a revision log message, so do not describe the changes made or the current state of the initial revision. Instead, this is a request for a description (see section on file descriptions) of the file. The description has no functional purpose in RCS. The description serves only to describe the file to you and others. This can be helpful when files are given obscure, non-descriptive file names, or impractical and vague names like the one used in this example. So names should describe what the purpose of the file is and what type a file is that is more expressive than the file name extension. In the example, the extension is .txt.

Descriptions, as RCS requests, must end with a single period (.), or an “end of file” character. An “end of file” character is issued on most systems by typing Ctrl D (^D). By “single”, RCS requests the period or end of file should be the only single-only character on the line. After entering the period a carriage return (on most systems enter or return) must be entered. A carriage return is not necessary after terminating the description with an “end of file”.

Here is a description entry for the initial revision of the example:

RCS/our_file.txt,v  <--  our_file.txt
enter description, terminated with single '.' or end of file:
NOTE: This is NOT the log message!
>> Our Example RCS Text File
>> .
initial revision: 1.1
done

Descriptions can also be provided as a command-line argument (see section on file description option), rather than taken from standard input.