Here's a quick example of an svn commit command in what I think is a very typical scenario. Assuming that I just made a few changes to some files in a directory, to commit those changes back to the repository, I just issue an "svn commit" command like this, incuding a nice svn commit message:
svn commit --message "Enabling build processes to support multiple platforms"
(Don't forget -- a good SVN commit message can really help you out later. I find it helps to say both what I did, and why I did it.)
A lot of times when working with SVN it's helpful to get a status showing all the changes you've made before issuing your commit command. With SVN, you get status information like this:
In the case of a project I'm currently working on, this svn status command just returned this information:
A build.alspc A antAlsPC.bat M build.xml