Nice svn pre-commit scripts

[Nguyen Vu Hung (VNC)]

Hello all,

1. I need a script that stops commits that have empty log messages. Like 
this
http://stackoverflow.com/questions/869248/windows-pre-commit-hook-for-comment-length-subversion
Is there any script that run both under Linux and Windows (better: 
written in Python)

2. Please point me to some nice pre-commit hooks you know :)

Thanks in advance,

Nguyen Vu Hung