Firstly you need to create a CVS repository somewhere for yourself. The mechanics of this are not straightforward so this is one I'll leave you to google for yourself.

Creating a module
First things first, you need to create a module directory in which to store all your files. To do this, create a temporary directory (make sure it is empty) such as tmp as follows:

  [/]$ mkdir tmp
  [/]$ cd tmp
  [tmp]$ cvs import myproject myname start
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You'll be asked to provide a comment, and you can type something like Created module directory.

Checking Out Module
Next, find somewhere to check your module directory out to.

  [tmp]$ cd ..
  [/]$ cvs co myproject
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This will create a directory called myproject and we will move into this directory now:

  [/]$ cd myproject
  [myproject]$
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Adding Files To Module
Copy your files into your myproject directory.

  [myproject]$ cp ../myperlcode.pl .
  [myproject]$
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Now we can add each file into the repository:

  [myproject]$ cvs add myperlcode.pl
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..and then commit the file..

  [myproject]$ cvs commit -m "Initial import" myperlcode.pl
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Bingo, your file is now in the repository.

Checking In A Change
Now edit your file myperlcode.pl where it is in the myproject directory. When you now run

  [myproject]$ cvs status myperlcode.pl
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..you'll see that CVS has detected you've changed the code. What differences are there between your edited version and the version stored?

  [myproject]$ cvs diff myperlcode.pl
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Checking in a change is simple, run

  [myproject]$ cvs commit -m "Minor change" myperlcode.pl
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Once you've done this, check the status again:

  [myproject]$ cvs status myperlcode.pl
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..and you'll see the file is up-to-date. And version 1.2 now too..

Show The History
You can view who has edited the file by running

  cvs log myperlcode.pl
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There's much more you can do.. this was just a very very brief overview, look at the documentation available on the web for better tutorials.