Anonymous CVS (or, as it is otherwise known, anoncvs) is a
feature provided by the CVS utilities bundled with FreeBSD for synchronizing
with a remote CVS repository. Among other things, it allows users of
FreeBSD to perform, with no special privileges, read-only CVS operations
against one of the FreeBSD project's official anoncvs servers. To use it,
one simply sets the CVSROOT environment variable to point at the
appropriate anoncvs server and then uses the cvs(1) command to
access it like any local repository.
While it can also be said that the and anoncvs
services both perform essentially the same function, there are various
trade-offs which can influence the user's choice of synchronization methods.
In a nutshell, CVSup is much more efficient in its usage of
network resources and is by far the most technically sophisticated of the
two, but at a price. To use CVSup, a special client must first be
installed and configured before any bits can be grabbed, and then only in
the fairly large chunks which CVSup calls collections.
Anoncvs, by contrast, can be used to examine anything from an
individual file to a specific program (like ls or grep)
by referencing the CVS module name. Of course, anoncvs is also
only good for read-only operations on the CVS repository, so if it's your
intention to support local development in one repository shared with the
FreeBSD project bits then CVSup is really your only option.
Using Anonymous CVS
Configuring cvs(1) to use an Anonymous CVS repository is
a simple matter of setting the CVSROOT environment
variable to point to one of the FreeBSD project's anoncvs
servers. At the time of this writing, the following servers are
available:
USA: anoncvs@anoncvs.freebsd.org:/cvs
Since CVS allows one to "check out" virtually any version of the FreeBSD
sources that ever existed (or, in some cases, will exist :), you need
to be familiar with the revision (-r) flag to cvs(1)
and what some of the permissible values for it in the FreeBSD Project
repository are.
There are two kinds of tags, revision tags and branch tags. A revision tag
refers to a specific revision. Its meaning stays the same from day to
day. A branch tag, on the other hand, refers to the latest revision
on a given line of development, at any given time. Because a branch
tag does not refer to a specific revision, it may mean something
different tomorrow than it means today.
Here are the branch tags that users might be interested in:
Here are the revision tags that users might be interested in:
When you specify a branch tag, you normally receive the latest versions
of the files on that line of development. If you wish to receive some
past version, you can do so by specifying a date with the -D date
flag. See the cvs(1) man page for more details.
Examples
While it really is recommended that you read the manual page for
cvs(1) thoroughly before doing anything, here are some quick
examples which essentially show how to use Anonymous CVS:
Checking out something from -current (ls(1)) and deleting it again:
% setenv CVSROOT anoncvs@anoncvs.freebsd.org:/cvs
% cvs co ls
% cvs release -d ls
Checking out the version of ls(1) in the 2.2-stable branch:
% setenv CVSROOT anoncvs@anoncvs.freebsd.org:/cvs
% cvs co -rRELENG_2_2 ls
% cvs release -d ls
Creating a list of changes (as unidiffs) to ls(1) between FreeBSD 2.2.2
and FreeBSD 2.2.6:
% setenv CVSROOT anoncvs@anoncvs.freebsd.org:/cvs
% cvs rdiff -u -rRELENG_2_2_2_RELEASE -rRELENG_2_2_6_RELEASE ls
Finding out what other module names can be used:
% setenv CVSROOT anoncvs@anoncvs.freebsd.org:/cvs
% cvs co modules
% more modules/modules
% cvs release -d modules
Other Resources
The following additional resources may be helpful in learning CVS:
from Cal Poly., commercial
maintainers of CVS.
is the FreeBSD Project web interface for CVS.