The message when nonexistent app is given should be improved. The current one is a bit cryptic (no such "child"?).
It should just say:
"Given input path was not found: /foo/bar/ABC"

[windup-distribution]$ windup-migrate-app --input /home/ondra/Desktop/WindupApps/ABC/abc.ear --output Report2
Exception when parsing/running: windup-migrate-app --input /home/ondra/Desktop/WindupApps/ABC/abc.ear --output Report2, no such child: ABC
java.lang.RuntimeException: no such child: ABC
at org.jboss.forge.addon.resource.util.ResourcePathResolver.resolve(ResourcePathResolver.java:235)
at org.jboss.forge.addon.shell.aesh.CommandLineUtil.populateUIInputs(CommandLineUtil.java:186)
at org.jboss.forge.addon.shell.aesh.ForgeCommandPopulator.populateObject(ForgeCommandPopulator.java:44)
at org.jboss.aesh.console.AeshConsoleImpl$AeshConsoleCallbackImpl.execute(AeshConsoleImpl.java:313)
at org.jboss.aesh.console.AeshProcess.run(AeshProcess.java:40)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)