After making a few changes in a directory, I issued a commit command like this:

svn commit --message "Enabling build processes to support multiple platforms"

Of course you may also want to get a status on your changes before performing a commit. With SVN you get status information like this:

svn status

Which, in my case, returned this information:

A      build.alspc
A      antAlsPC.bat
M      build.xml