diff --git a/command/plugin.go b/command/plugin.go
index 1685db188..57d6f0299 100644
--- a/command/plugin.go
+++ b/command/plugin.go
@@ -3,7 +3,6 @@ package command
 import (
 	"fmt"
 	"log"
-	"os"
 	"strings"
 
 	"github.com/mitchellh/packer/builder/amazon/chroot"
@@ -105,7 +104,7 @@ func (c *PluginCommand) Run(args []string) int {
 	log.Printf("args: %#v", args)
 	if len(args) != 1 {
 		c.Ui.Error("Wrong number of args")
-		os.Exit(1)
+		return 1
 	}
 
 	// Plugin should be called like "packer-builder-amazon-ebs" so we'll take it
@@ -124,25 +123,29 @@ func (c *PluginCommand) Run(args []string) int {
 
 	server, err := plugin.Server()
 	if err != nil {
-		panic(err)
+		c.Ui.Error(fmt.Sprintf("Error starting plugin server: %s", err))
+		return 1
 	}
 
 	if pluginType == "builder" {
 		builder, found := Builders[pluginName]
 		if !found {
 			c.Ui.Error(fmt.Sprintf("Could not load builder: %s", pluginName))
+			return 1
 		}
 		server.RegisterBuilder(builder)
 	} else if pluginType == "provisioner" {
 		provisioner, found := Provisioners[pluginName]
 		if !found {
 			c.Ui.Error(fmt.Sprintf("Could not load provisioner: %s", pluginName))
+			return 1
 		}
 		server.RegisterProvisioner(provisioner)
 	} else if pluginType == "post-processor" {
 		postProcessor, found := PostProcessors[pluginName]
 		if !found {
 			c.Ui.Error(fmt.Sprintf("Could not load post-processor: %s", pluginName))
+			return 1
 		}
 		server.RegisterPostProcessor(postProcessor)
 	}
@@ -156,13 +159,14 @@ func (*PluginCommand) Help() string {
 	helpText := `
 Usage: packer plugin PLUGIN
 
-  Runs an internally-compiled version of a plugin from the packer binary. Note
-  that this is an internal command and you should not call it yourself.
+  Runs an internally-compiled version of a plugin from the packer binary.
+
+  NOTE: this is an internal command and you should not call it yourself.
 `
 
 	return strings.TrimSpace(helpText)
 }
 
 func (c *PluginCommand) Synopsis() string {
-	return "call an internal plugin"
+	return "internal plugin command"
 }
diff --git a/config.go b/config.go
index 004315489..a122b120d 100644
--- a/config.go
+++ b/config.go
@@ -16,6 +16,10 @@ import (
 	"github.com/mitchellh/packer/packer/plugin"
 )
 
+// PACKERSPACE is used to represent the spaces that separate args for a command
+// without being confused with spaces in the path to the command itself.
+const PACKERSPACE = "-PACKERSPACE-"
+
 type config struct {
 	DisableCheckpoint          bool `json:"disable_checkpoint"`
 	DisableCheckpointSignature bool `json:"disable_checkpoint_signature"`
@@ -80,7 +84,7 @@ func (c *config) Discover() error {
 		return err
 	}
 
-	// Finally, try to use an internal plugin. Note that this will not Override
+	// Finally, try to use an internal plugin. Note that this will not override
 	// any previously-loaded plugins.
 	if err := c.discoverInternal(); err != nil {
 		return err
@@ -216,7 +220,8 @@ func (c *config) discoverInternal() error {
 		_, found := (c.Builders)[builder]
 		if !found {
 			log.Printf("Using internal plugin for %s", builder)
-			(c.Builders)[builder] = fmt.Sprintf("%s-PACKERSPACE-plugin-PACKERSPACE-packer-builder-%s", packerPath, builder)
+			(c.Builders)[builder] = fmt.Sprintf("%s%splugin%spacker-builder-%s",
+				packerPath, PACKERSPACE, PACKERSPACE, builder)
 		}
 	}
 
@@ -224,7 +229,9 @@ func (c *config) discoverInternal() error {
 		_, found := (c.Provisioners)[provisioner]
 		if !found {
 			log.Printf("Using internal plugin for %s", provisioner)
-			(c.Provisioners)[provisioner] = fmt.Sprintf("%s-PACKERSPACE-plugin-PACKERSPACE-packer-provisioner-%s", packerPath, provisioner)
+			(c.Provisioners)[provisioner] = fmt.Sprintf(
+				"%s%splugin%spacker-provisioner-%s",
+				packerPath, PACKERSPACE, PACKERSPACE, provisioner)
 		}
 	}
 
@@ -232,7 +239,9 @@ func (c *config) discoverInternal() error {
 		_, found := (c.PostProcessors)[postProcessor]
 		if !found {
 			log.Printf("Using internal plugin for %s", postProcessor)
-			(c.PostProcessors)[postProcessor] = fmt.Sprintf("%s-PACKERSPACE-plugin-PACKERSPACE-packer-post-processor-%s", packerPath, postProcessor)
+			(c.PostProcessors)[postProcessor] = fmt.Sprintf(
+				"%s%splugin%spacker-post-processor-%s",
+				packerPath, PACKERSPACE, PACKERSPACE, postProcessor)
 		}
 	}
 
@@ -259,8 +268,8 @@ func (c *config) pluginClient(path string) *plugin.Client {
 
 	// Check for special case using `packer plugin PLUGIN`
 	args := []string{}
-	if strings.Contains(path, "-PACKERSPACE-") {
-		parts := strings.Split(path, "-PACKERSPACE-")
+	if strings.Contains(path, PACKERSPACE) {
+		parts := strings.Split(path, PACKERSPACE)
 		path = parts[0]
 		args = parts[1:]
 	}