mvn help:help

help:active-profiles
  Displays a list of the profiles which are currently active for this build.

help:all-profiles
  Displays a list of available profiles under the current project.
  Note: it will list all profiles for a project. If a profile comes up with a
  status inactive then there might be a need to set profile activation
  switches/property.

help:describe
  Displays a list of the attributes for a Maven Plugin and/or goals (aka Mojo -
  Maven plain Old Java Object).

help:effective-pom
  Displays the effective POM as an XML for this build, with the active profiles
  factored in, or a specified artifact. If verbose, a comment is added to each
  XML element describing the origin of the line.

help:effective-settings
  Displays the calculated settings as XML for this project, given any profile
  enhancement and the inheritance of the global settings into the user-level
  settings.

help:evaluate
  Evaluates Maven expressions given by the user in an interactive mode.

help:help
  Display help information on maven-help-plugin.
  Call mvn help:help -Ddetail=true -Dgoal=<goal-name> to display parameter
  details.

help:system
  Displays a list of the platform details like system properties and environment
  variables.

This plugin has 21 goals:

dependency:analyze
  Analyzes the dependencies of this project and determines which are: used and
  declared; used and undeclared; unused and declared. This goal is intended to
  be used standalone, thus it always executes the test-compile phase - use the
  dependency:analyze-only goal instead when participating in the build
  lifecycle.
  By default, maven-dependency-analyzer is used to perform the analysis, with
  limitations due to the fact that it works at bytecode level, but any analyzer
  can be plugged in through analyzer parameter.

dependency:analyze-dep-mgt
  This mojo looks at the dependencies after final resolution and looks for
  mismatches in your dependencyManagement section. In versions of maven prior to
  2.0.6, it was possible to inherit versions that didn't match your
  dependencyManagement. See MNG-1577 for more info. This mojo is also useful for
  just detecting projects that override the dependencyManagement directly. Set
  ignoreDirect to false to detect these otherwise normal conditions.

dependency:analyze-duplicate
  Analyzes the <dependencies/> and <dependencyManagement/> tags in the pom.xml
  and determines the duplicate declared dependencies.

dependency:analyze-only
  Analyzes the dependencies of this project and determines which are: used and
  declared; used and undeclared; unused and declared. This goal is intended to
  be used in the build lifecycle, thus it assumes that the test-compile phase
  has been executed - use the dependency:analyze goal instead when running
  standalone.
  By default, maven-dependency-analyzer is used to perform the analysis, with
  limitations due to the fact that it works at bytecode level, but any analyzer
  can be plugged in through analyzer parameter.

dependency:analyze-report
  Analyzes the dependencies of this project and produces a report that
  summarizes which are: used and declared; used and undeclared; unused and
  declared.

dependency:build-classpath
  This goal will output a classpath string of dependencies from the local
  repository to a file or log.

dependency:copy
  Goal that copies a list of artifacts from the repository to defined locations.

dependency:copy-dependencies
  Goal that copies the project dependencies from the repository to a defined
  location.

dependency:get
  Resolves a single artifact, eventually transitively, from the specified remote
  repositories. Caveat: will always check the central repository defined in the
  super pom. You could use a mirror entry in your settings.xml

dependency:go-offline
  Goal that resolves all project dependencies, including plugins and reports and
  their dependencies.

dependency:help
  Display help information on maven-dependency-plugin.
  Call mvn dependency:help -Ddetail=true -Dgoal=<goal-name> to display parameter
  details.

dependency:list
  Displays the list of dependencies for this project.

dependency:list-repositories
  Goal that resolves all project dependencies and then lists the repositories
  used by the build and by the transitive dependencies

dependency:properties
  Goal that sets a property pointing to the artifact file for each project
  dependency. For each dependency (direct and transitive) a project property
  will be set which follows the groupId:artifactId:type:[classifier] form and
  contains the path to the resolved artifact.

dependency:purge-local-repository
  Remove the project dependencies from the local repository, and optionally
  re-resolve them.

dependency:resolve
  Goal that resolves the project dependencies from the repository.

dependency:resolve-plugins
  Goal that resolves all project plugins and reports and their dependencies.

dependency:sources
  Goal that resolves the project source dependencies from the repository.

dependency:tree
  Displays the dependency tree for this project.

dependency:unpack
  Goal that retrieves a list of artifacts from the repository and unpacks them
  in a defined location.

dependency:unpack-dependencies
  Goal that unpacks the project dependencies from the repository to a defined
  location.