Maven Help Command

When we are struck with some aspect of Maven, Plugin’s Help goal and Maven Help Plugin comes handy to navigate output of the situation.

Here we present some the useful Maven help commands as reference.

Find Plugin Prefix

In almost all Maven plugin related commands we need to use Plugin Prefix. We can find plugin prefixes in Maven Plugin Directory. The first column of the table contains the Plugin Prefixes.

For plugins not listed there, use help:describe to show the prefix.

$ mvn help:describe -DgroupId=<group-id> -DartifactId=<artifact-id>

## examples

$ mvn help:describe -DgroupId=org.mortbay.jetty -DartifactId=jetty-maven-plugin
$ mvn help:describe -DgroupId=org.codehaus.mojo -DartifactId=aspectj-maven-plugin
Useful Maven Help Commands - show goal prefix

List Plugin Goals

The easiest way to list the plugin goal is plugins help goal.

$ mvn <plugin-prefix>:help

## examples

$ mvn compiler:help
$ mvn surefire:help
$ mvn jar:help

List Parameters of a Goal

To list parameters of a goal, invoke plugin’s help goal with -Dgoal=<goal name> and -Ddetail.

$ mvn <plugin-prefix>:help -Dgoal=<goal name> -Ddetail

## examples

$ mvn compiler:help -Dgoal=compile -Ddetail
$ mvn surefire:help -Dgoal=test -Ddetail
 
 

List Parameters with default values

Some of the plugins, show default values for the parameter with plugins help.

$ mvn <plugin-prefix>:help -Dgoal=<goal-name> -Ddetail

## examples

$ mvn jar:help -Dgoal=jar -Ddetail

However, help:describe shows default parameter values for all plugins.

mvn help:describe -Dplugin=<plugin-prefix> -Dmojo=<goal-name> -Ddetail

## examples

mvn help:describe -Dplugin=jar -Dmojo=jar -Ddetail

Important

To pass goal name as parameter, in plugin’s help use -Dgoal and in help:describe use -Dmojo.

List Lifecycle Phases

To know the lifecycle phases and the binded goals use following command.

$ mvn help:describe -Dcmd=<lifecycle-phase-name>

## examples

$ mvn help:describe -Dcmd=compile
$ mvn help:describe -Dcmd=clean
 
 

Effective POM

To output effective POM, use following command.

$ mvn help:effective-pom

## to output to file

$ mvn help:effective-pom -Doutput=<file-name>