CVS Cheat Sheet

To use CVS properly, you should (must) have an SSH agent with your SSH key, and have your SSH public key in your .ssh/authorized_keys file on our CVS server. Test using ssh cvs.bcl.hamilton.ie pwd. No password should be needed!

lab CVS server: cvs.bcl.hamilton.ie, or maybe just cvs-bcl if you're in the right domain
lab CVS root: /home/cvs
to set up access:
- export CVSROOT=:ext:cvs-bcl:/home/cvs
- export CVS_RSH=ssh
to get your new local copy set up
- papers: cvs checkout papers
- source: cvs checkout meg

The online text Open Source Development With CVS is an excellent reference.

CVS Dos and Don'ts

Please do not let a little knowledge become a dangerous thing: don't manually manipulate the repository!
Only ASCII files written by human beings belong in CVS. This includes programming language source code, latex source code, texinfo documentation, and shell scripts. Files generated by computer programs, or binary files, do not belong in CVS! This includes in particular: bitmaps, postscript, dvi files, tar files, Makefiles generated by ./configure, data files, foo.d files generated by gcc -MMD foo.c as in our standard build system, log files, etc. If it can be regenerated by an automatic tool it is a derived file and not a source file, and doesn't belong in CVS.
If you didn't edit it yourself, using a text editor, it doesn't belong in CVS.
External software packages which we are not ourselves modifying do not belong in our CVS repository. Not even as a subdirectory.
In general, you should add and commit files one by one, and not en mass. Emacs M-x cvs-update makes this easy.
CVS does not obviate the need for documentation. Every program we write should have a brief README file explaining what it does. And if it requires anything other than make on a stock stable Debian install, there must be an INSTALL file explaining what is needed to build it. In particular, if you need to manually install the libhorriblulus library, version 0.666, which is not available as a debian package, your INSTALL file must contain a paragraph explaining:
1. why you feel you need libhorribulus;
2. where exactly you downloaded libhorribulus from, meaning the exact url, version, and date;
3. exactly how you installed libhorribulus, where exactly means just that: the sequence of commands including all options, not just ``I followed the directions.''
Unless imported from elsewhere, or difficult for some reason, all files in CVS should have a ``version control block'' at the top. These help us track changes made outside of CVS, eg by collaborators. Just paste the appropriate header depending on the file type.
- C
- C++
- Scheme
- Makefile
- Matlab
- latex
- texinfo (requires usual .tex header but it must go before the "\input texinfo" line)
- shell script
- perl
- html
- Haskell

Useful Commands

Check out local copy

rm -rf meg
export CVS_RSH=ssh
cvs -d :ext:cvs.bcl.hamilton.ie:/home/cvs checkout meg

Commit your changes to the repository

cvs commit -m 'add --help switch' foo.c

Integrate other people's commits (if any) into your copy

cvs update foo.c

Delete a file from the repository

rm foo.cc
cvs remove foo.cc
cvs commit -m 'contents moved to file bar.cc' foo.cc

Note that the file's past continues to exist in the repository, so you can fetch old versions, examine its log, etc.

History

Difference between file in sandbox and head version in repository.

cvs diff file.cc

Examine history of a file. Works even if file is deleted in current version.

cvs log file.cc | more

Difference between specified versions.

cvs diff -r1.23 -r1.24 file.cc

Request particular version from repository. Works even if file is deleted in current version.

cvs update -r1.23 file.cc

Request head version from repository.

cvs update -A file.cc

Drop local changes

rm file.cc
cvs update file.cc

Symbolic labels

Label current version in repository with symbolic tag.

cvs tag handin-28-Jan-2001 foo.c bar.c foo.h bar.h Makefile

Set a watch

These arrange to send you email every time someone commits a change to the file foo.cc (first line) or any file in or below the directory in question (second line).

cvs watch add foo.cc
cvs watch add

Note that you probably need to create a file ~/.forward containing your preferred email address on the CVS server. Eg:

echo my_email@address.ie | ssh cvs.bcl.hamilton.ie "cat > ~/.forward"

Emacs and CVS

Emacs has a nice interface to CVS. You check things out from outside emacs, but when editing it rocks. The modeline displays the CVS revision number. To talk to CVS do

  M-x cvs-update

In the resulting *cvs* buffer go C-h m for documentation on available commands.

Important *cvs* buffer commands:

  a             add
  c             commit, then C-c C-c in the resulting log entry buffer
  d d           diff against repository

You can also use version control commands while in the buffer with the file itself.

  C-x v =      diff against repository
  C-x v l      show log of change history
  C-x v v      commit changes, then C-c C-c in resulting log entry buffer

Random Information

Here are random tidbits of information useful only under special circumstances.

If someone uses ssh2 instead of the superior and more widely used and properly free OpenSSH, they may have an "ssh2-format public key". Note that ssh2 and OpenSSH both support version 2 of the SSH protocol, and can inter-operate. It is only the key files that are incompatible. (And the ssh2 developers' attitude, which is incompatible with a fully open Internet infrastructure and community-based security, but that's another question.)
Fortunately, according to an ssh2-OpenSSH FAQ, there is a simple command to convert:
```
ssh-keygen -i -f ssh2_key.pub > ~/.ssh/openssh_key.pub
```

last update: $Date: 2007-12-18 11:17:41 $