I did everything the book says, i.e. removed the authentication files from .subversion/auth, and explicitly set the relevant configuration parameters to 'yes' even though this is a default, and yet the shell SVN commands ask for a password each time. The repository is on cvsdude.com, and the client is Linux. I also use the Subclipse plugin that caches the password OK.
I vaguely remember that when I started working with it, the command asked interactively if I wanted to save clear password, and I said no. Can this choice be stored somewhere and take precedence over the configuration?
Thanks to your comments I found the problem - it's the settings in the servers file (don't store plain passwords). I wonder why there is this redundancy with the [auth] section of the configuration file. The SVN book also does not mention this when talking about storing passwords.