commands: introduce plugin as alias to plugins

command/plugin.go

@@ -0,0 +1,32 @@
+package command
+
+import (
+	"strings"
+
+	"github.com/mitchellh/cli"
+)
+
+type PluginCommand struct {
+	Meta
+}
+
+func (c *PluginCommand) Synopsis() string {
+	return "Alias to `packer plugins` - Interact with Packer plugins and catalog"
+}
+
+func (c *PluginCommand) Help() string {
+	helpText := `
+Usage: packer plugin <subcommand> [options] [args]
+  This command groups subcommands for interacting with Packer plugins.
+
+Related but not under the "plugin" command :
+
+- "packer init <path>" will install all plugins required by a config.
+`
+
+	return strings.TrimSpace(helpText)
+}
+
+func (c *PluginCommand) Run(args []string) int {
+	return cli.RunResultHelp
+}

commands.go

@@ -65,30 +65,56 @@ func init() {
 			}, nil
 		},
 
+		"plugin": func() (cli.Command, error) {
+			return &command.PluginCommand{
+				Meta: *CommandMeta,
+			}, nil
+		},
+
 		"plugins": func() (cli.Command, error) {
 			return &command.PluginsCommand{
 				Meta: *CommandMeta,
 			}, nil
 		},
 
+		"plugin installed": func() (cli.Command, error) {
+			return &command.PluginsInstalledCommand{
+				Meta: *CommandMeta,
+			}, nil
+		},
 		"plugins installed": func() (cli.Command, error) {
 			return &command.PluginsInstalledCommand{
 				Meta: *CommandMeta,
 			}, nil
 		},
 
+		"plugin install": func() (cli.Command, error) {
+			return &command.PluginsInstallCommand{
+				Meta: *CommandMeta,
+			}, nil
+		},
 		"plugins install": func() (cli.Command, error) {
 			return &command.PluginsInstallCommand{
 				Meta: *CommandMeta,
 			}, nil
 		},
 
+		"plugin remove": func() (cli.Command, error) {
+			return &command.PluginsRemoveCommand{
+				Meta: *CommandMeta,
+			}, nil
+		},
 		"plugins remove": func() (cli.Command, error) {
 			return &command.PluginsRemoveCommand{
 				Meta: *CommandMeta,
 			}, nil
 		},
 
+		"plugin required": func() (cli.Command, error) {
+			return &command.PluginsRequiredCommand{
+				Meta: *CommandMeta,
+			}, nil
+		},
 		"plugins required": func() (cli.Command, error) {
 			return &command.PluginsRequiredCommand{
 				Meta: *CommandMeta,