Change the way aliases to subcommands are handled.

cmd/juju/destroyenvironment.go

 package main
 
 import (
         "launchpad.net/gnuflag"
         "launchpad.net/juju-core/cmd"
         "launchpad.net/juju-core/environs"
 )
 
 // DestroyEnvironmentCommand destroys an environment.
 type DestroyEnvironmentCommand struct {
         EnvName string
 }
 
 func (c *DestroyEnvironmentCommand) Info() *cmd.Info {
-        return cmd.NewInfo(
-                "destroy-environment", "[options]",
-                "terminate all machines and other associated resources for an environment",
-                "",
-        )
+        return &cmd.Info{
+                Name:    "destroy-environment",
+                Purpose: "terminate all machines and other associated resources for an environment",
+        }
 }
 
 func (c *DestroyEnvironmentCommand) SetFlags(f *gnuflag.FlagSet) {
         addEnvironFlags(&c.EnvName, f)
 }
 
 func (c *DestroyEnvironmentCommand) Init(args []string) error {
         return cmd.CheckEmpty(args)
 }
 
 func (c *DestroyEnvironmentCommand) Run(_ *cmd.Context) error {
         environ, err := environs.NewFromName(c.EnvName)
         if err != nil {
                 return err
         }
         return environ.Destroy(nil)
 }