The Maven SCM plugin allows you to perform some common SCM actions.
This command is usually performed without a project, as that is what you are
checking out, so you need to specify the
SCM URL. The URL takes the same format
as the <repository><connection>
element in your project.xml
file.
maven scm:checkout -Dmaven.scm.url=scm:svn:http://svn.apache.org/repos/asf/maven/maven-1/core/trunk