Add validate command for validating Vagrantfile

plugins/commands/validate/command.rb

@@ -0,0 +1,31 @@
+require 'optparse'
+
+module VagrantPlugins
+  module CommandValidate
+    class Command < Vagrant.plugin("2", :command)
+      def self.synopsis
+        "validates the Vagrantfile"
+      end
+
+      def execute
+        opts = OptionParser.new do |o|
+          o.banner = "Usage: vagrant validate"
+        end
+
+        # Parse the options
+        argv = parse_options(opts)
+        return if !argv
+
+        # Validate the configuration
+        @env.machine(@env.machine_names.first, @env.default_provider).action_raw(
+          :config_validate,
+          Vagrant::Action::Builtin::ConfigValidate)
+
+        @env.ui.info(I18n.t("vagrant.commands.validate.success"))
+
+        # Success, exit status 0
+        0
+      end
+    end
+  end
+end

plugins/commands/validate/plugin.rb

@@ -0,0 +1,17 @@
+require "vagrant"
+
+module VagrantPlugins
+  module CommandValidate
+    class Plugin < Vagrant.plugin("2")
+      name "validate command"
+      description <<-DESC
+      The `validate` command validates the Vagrantfile.
+      DESC
+
+      command("validate") do
+        require File.expand_path("../command", __FILE__)
+        Command
+      end
+    end
+  end
+end

templates/locales/en.yml

@@ -1726,6 +1726,9 @@ en:
       up:
         upping: |-
           Bringing machine '%{name}' up with '%{provider}' provider...
+      validate:
+        success: |-
+          Vagrantfile validated successfully.
 
 #-------------------------------------------------------------------------------
 # Translations for Vagrant middleware actions