CVS Instructions

CVS is a version-control system. That is, you can use it to keep track of multiple versions of files. The idea is that you do some work on your code and test it, then check it into the version-control system. If you decide that the work you've done since your last check-in is no good, you can easily revert to the last checked-in version. Furthermore, you can retrieve any old version of your code as of some given day and time. The version control logs tell you who made changes and when.

CVS is not the best version control system out there, but it's free and is fairly easy to use.

For more information, visit the CVS home page.

Setting Up CVS

To set up CVS, start by choosing one group member as the keeper of the CVS repository. Everyone in the group will be able to use the CVS repository, but the keeper will actually create the repository and maintain permissions for its contents.

The following instructions are specific to our local setup for the Fall 2006 semester. Even if you've used CVS before, we ask that you read the instructions in their entirety.

Repositories must be created on the machine ''. This machine contains a directory that was specially set up for CS 4244 students' CVS repositories. To access the repository from the other machines, you should first configure ssh to log you on automatically, without requiring a password every time. See section F.2.4 Setting Up ssh, for more information. To connect to this machine use ssh ap2 from any of the machines in McB 124. You should not be prompted for a password if you have configured ssh properly.

The keeper has to perform several steps to set up the repository. First, log on to '' and create a directory for storing the repository. The new directory must be created in the directory /shared/cs4244 and should be named Proj-keeper_pid, where keeper_pid is the pid of the keeper. Next, configure access to repository using the command setfacl --set u::rwx,g::---,o::--- Proj-keeper_pid. This command ensures that the user, i.e the keeper has the required permissions to access the repository, and no one else does. To set permissions for the other members in the group, use setfacl -m u:member_pid:rwx Proj-keeper_pid for each of the other members in the group, replacing member_pid with the pid of the group member.

Next, set the permissions of the directories and files that would be created inside the repository using the command setfacl -d --set u::rwx,g::---,o::--- Proj-keeper_pid. To permit all the members of the group access to all the files and directories created in the repository, use setfacl -d -m u:member_pid:rwx Proj-keeper_pid once for each group member (should be used once for the keeper too), replacing member_pid with the pid of the group member. To make sure that the permissions are set correctly, use getfacl Proj-keeper_pid.

Note that neither (Unix-) group members nor others should have read access to your CVS repository, hence the g::---,o::--- part of the access control list. (Giving access to group members (in the Unix sense) would give access to, for instance, all CS majors if your default (Unix-) group is Major. We use ACLs to give individual access to your CS 4244 group members.) Failing to protect your repository in this way is an honor code violation.

Now initialize the repository. To initialize the repository, execute cvs -d /shared/cs4244/Proj-keeper_pid init.

Finally, import your source files into the newly initialized repository. If you have an existing set of source files you want to add to the repository, cd to its directory now.

cvs -d /shared/cs4244/Proj-keeper_pid import -m "Imported sources" foobar start

Here is a summary of the commands you have now executed:


cd /shared/cs4244
mkdir Proj-keeper_pid
setfacl --set u::rwx,g::---,o::--- Proj-keeper_pid
# for all other group members do:
setfacl -m u:member-pid:rwx Proj-keeper_pid
setfacl -d --set u::rwx,g::---,o::--- Proj-keeper_pid
# for all group members, including the keeper, do:
setfacl -d -m u:member_pid:rwx Proj-keeper_pid
cvs -d /shared/cs4244/Proj-keeper_pid init

The repository is now ready for use by any group member, as described below. Having set the repository up, you need not log on to '' for any other purposes. Keep in mind that the repository should only be accessed using CVS commands--it is not generally useful to examine the repository files by hand, and you should definitely not modify them yourself.

Due to space constraints, ''should be used only to store the repository and not for development purposes. Do not store any other files there and do not run any other programs on this machine. The reason for this somewhat unusual setup is that our shared file servers currently do not support the setfacl commands, making it impossible to protect your CVS repository.

Using CVS

I strongly suggest that you use the Eclipse CVS integration facilities.

See the following links for details:


This document was adapted from the materials originally developed for CS3204