Here are some Maven2 command lines that I use most often:
To create a new project:
mvn archetype:create -DgroupId=com.mbledug.foo -DartifactId=bar
To generate Eclipse project descriptor after configuring the dependencies in pom.xml:
mvn eclipse:eclipse
To run unit tests, obviously:
mvn test
Tun run a single test by test class name:
mvn test -Dtest=FooBar
To generate site documentation without running the tests (handy while updating the APTs):
mvn -Dmaven.test.skip=true clean site
To build the package file (jar, war, etc) allowing test failure:
mvn -Dmaven.test.failure.ignore=true package
To distribute the source code:
mvn assembly:assembly -DdescriptorId=src
To install a jar file on local repo:
mvn install:install-file -Dfile=foo.jar -DgroupId=bar -Dversion=x.y -Dpackaging=jar -DartifactId=blah
To release an artifact (create a tag in the SCM and bump up SNAPSHOT version in the pom):
mvn release:prepare release:perform