diff --git a/Godeps/Godeps.json b/Godeps/Godeps.json
index 1859128a..68156557 100644
--- a/Godeps/Godeps.json
+++ b/Godeps/Godeps.json
@@ -314,11 +314,12 @@
 		},
 		{
 			"ImportPath": "github.com/spf13/cobra",
-			"Rev": "b4dbd37a01839e0653eec12aa4bbb2a2ce7b2a37"
+			"Rev": "b78744579491c1ceeaaa3b40205e56b0591b93a3"
 		},
 		{
 			"ImportPath": "github.com/spf13/pflag",
-			"Rev": "e57e3eeb33f795204c1ca35f56c44f83227c6e66"
+			"Comment": "v1.0.0-3-g7aff26d",
+			"Rev": "7aff26db30c1be810f9de5038ec5ef96ac41fd7c"
 		},
 		{
 			"ImportPath": "golang.org/x/crypto/ssh/terminal",
diff --git a/cmd/analyze.go b/cmd/analyze.go
index a06284da..577dc490 100644
--- a/cmd/analyze.go
+++ b/cmd/analyze.go
@@ -32,15 +32,16 @@ var analyzeCmd = &cobra.Command{
 	Use:   "analyze",
 	Short: "Analyzes an image: [image]",
 	Long:  `Analyzes an image using the specifed analyzers as indicated via flags (see documentation for available ones).`,
-	Run: func(cmd *cobra.Command, args []string) {
+	Args: func(cmd *cobra.Command, args []string) error {
 		if err := validateArgs(args, checkAnalyzeArgNum, checkArgType); err != nil {
-			glog.Error(err.Error())
-			os.Exit(1)
+			return errors.New(err.Error())
 		}
 		if err := checkIfValidAnalyzer(types); err != nil {
-			glog.Error(err)
-			os.Exit(1)
+			return errors.New(err.Error())
 		}
+		return nil
+	},
+	Run: func(cmd *cobra.Command, args []string) {
 		if err := analyzeImage(args[0], strings.Split(types, ",")); err != nil {
 			glog.Error(err)
 			os.Exit(1)
@@ -49,11 +50,8 @@ var analyzeCmd = &cobra.Command{
 }
 
 func checkAnalyzeArgNum(args []string) error {
-	var errMessage string
 	if len(args) != 1 {
-		errMessage = "'analyze' requires one image as an argument: container analyze [image]"
-		glog.Errorf(errMessage)
-		return errors.New(errMessage)
+		return errors.New("'analyze' requires one image as an argument: container analyze [image]")
 	}
 	return nil
 }
diff --git a/cmd/diff.go b/cmd/diff.go
index 9f083e04..4c9b1731 100644
--- a/cmd/diff.go
+++ b/cmd/diff.go
@@ -33,15 +33,16 @@ var diffCmd = &cobra.Command{
 	Use:   "diff",
 	Short: "Compare two images: [image1] [image2]",
 	Long:  `Compares two images using the specifed analyzers as indicated via flags (see documentation for available ones).`,
-	Run: func(cmd *cobra.Command, args []string) {
+	Args: func(cmd *cobra.Command, args []string) error {
 		if err := validateArgs(args, checkDiffArgNum, checkArgType); err != nil {
-			glog.Error(err.Error())
-			os.Exit(1)
+			return errors.New(err.Error())
 		}
 		if err := checkIfValidAnalyzer(types); err != nil {
-			glog.Error(err)
-			os.Exit(1)
+			return errors.New(err.Error())
 		}
+		return nil
+	},
+	Run: func(cmd *cobra.Command, args []string) {
 		if err := diffImages(args[0], args[1], strings.Split(types, ",")); err != nil {
 			glog.Error(err)
 			os.Exit(1)
@@ -50,10 +51,8 @@ var diffCmd = &cobra.Command{
 }
 
 func checkDiffArgNum(args []string) error {
-	var errMessage string
 	if len(args) != 2 {
-		errMessage = "'diff' requires two images as arguments: container diff [image1] [image2]"
-		return errors.New(errMessage)
+		return errors.New("'diff' requires two images as arguments: container diff [image1] [image2]")
 	}
 	return nil
 }
diff --git a/cmd/version.go b/cmd/version.go
index d2bb39cd..42ad0bd7 100644
--- a/cmd/version.go
+++ b/cmd/version.go
@@ -27,6 +27,7 @@ var versionCmd = &cobra.Command{
 	Use:   "version",
 	Short: "Print the version of container-diff",
 	Long:  `Print the version of container-diff.`,
+	Args:  cobra.ExactArgs(0),
 	Run: func(command *cobra.Command, args []string) {
 		fmt.Println(version.GetVersion())
 	},
diff --git a/vendor/github.com/spf13/cobra/.travis.yml b/vendor/github.com/spf13/cobra/.travis.yml
index cb2bf0d5..68efa136 100644
--- a/vendor/github.com/spf13/cobra/.travis.yml
+++ b/vendor/github.com/spf13/cobra/.travis.yml
@@ -2,8 +2,8 @@ language: go
 
 matrix:
   include:
-    - go: 1.7.5
-    - go: 1.8.1
+    - go: 1.7.6
+    - go: 1.8.3
     - go: tip
   allow_failures:
     - go: tip
diff --git a/vendor/github.com/spf13/cobra/README.md b/vendor/github.com/spf13/cobra/README.md
index ff844d2c..da9aa881 100644
--- a/vendor/github.com/spf13/cobra/README.md
+++ b/vendor/github.com/spf13/cobra/README.md
@@ -117,14 +117,6 @@ Flag functionality is provided by the [pflag
 library](https://github.com/spf13/pflag), a fork of the flag standard library
 which maintains the same interface while adding POSIX compliance.
 
-## Usage
-
-Cobra works by creating a set of commands and then organizing them into a tree.
-The tree defines the structure of the application.
-
-Once each command is defined with its corresponding flags, then the
-tree is assigned to the commander which is finally executed.
-
 # Installing
 Using Cobra is easy. First, use `go get` to install the latest version
 of the library. This command will install the `cobra` generator executable
@@ -140,8 +132,8 @@ import "github.com/spf13/cobra"
 
 # Getting Started
 
-While you are welcome to provide your own organization, typically a Cobra based
-application will follow the following organizational structure.
+While you are welcome to provide your own organization, typically a Cobra-based
+application will follow the following organizational structure:
 
 ```
   ▾ appName/
@@ -153,23 +145,23 @@ application will follow the following organizational structure.
       main.go
 ```
 
-In a Cobra app, typically the main.go file is very bare. It serves, one purpose, to initialize Cobra.
+In a Cobra app, typically the main.go file is very bare. It serves one purpose: initializing Cobra.
 
 ```go
 package main
 
 import (
-	"fmt"
-	"os"
+  "fmt"
+  "os"
 
-	"{pathToYourApp}/cmd"
+  "{pathToYourApp}/cmd"
 )
 
 func main() {
-	if err := cmd.RootCmd.Execute(); err != nil {
-		fmt.Println(err)
-		os.Exit(1)
-	}
+  if err := cmd.RootCmd.Execute(); err != nil {
+    fmt.Println(err)
+    os.Exit(1)
+  }
 }
 ```
 
@@ -216,10 +208,11 @@ cobra add create -p 'configCmd'
 ```
 
 *Note: Use camelCase (not snake_case/snake-case) for command names.
-Otherwise, you will become unexpected errors.
+Otherwise, you will encounter errors.
 For example, `cobra add add-user` is incorrect, but `cobra add addUser` is valid.*
 
-Once you have run these three commands you would have an app structure that would look like:
+Once you have run these three commands you would have an app structure similar to
+the following:
 
 ```
   ▾ app/
@@ -232,14 +225,14 @@ Once you have run these three commands you would have an app structure that woul
 
 At this point you can run `go run main.go` and it would run your app. `go run
 main.go serve`, `go run main.go config`, `go run main.go config create` along
-with `go run main.go help serve`, etc would all work.
+with `go run main.go help serve`, etc. would all work.
 
-Obviously you haven't added your own code to these yet, the commands are ready
+Obviously you haven't added your own code to these yet. The commands are ready
 for you to give them their tasks. Have fun!
 
 ### Configuring the cobra generator
 
-The cobra generator will be easier to use if you provide a simple configuration
+The Cobra generator will be easier to use if you provide a simple configuration
 file which will help you eliminate providing a bunch of repeated information in
 flags over and over.
 
@@ -269,7 +262,7 @@ You can also use built-in licenses. For example, **GPLv2**, **GPLv3**, **LGPL**,
 
 ## Manually implementing Cobra
 
-To manually implement cobra you need to create a bare main.go file and a RootCmd file.
+To manually implement Cobra you need to create a bare main.go file and a RootCmd file.
 You will optionally provide additional commands as you see fit.
 
 ### Create the root command
@@ -284,14 +277,14 @@ Ideally you place this in app/cmd/root.go:
 
 ```go
 var RootCmd = &cobra.Command{
-	Use:   "hugo",
-	Short: "Hugo is a very fast static site generator",
-	Long: `A Fast and Flexible Static Site Generator built with
+  Use:   "hugo",
+  Short: "Hugo is a very fast static site generator",
+  Long: `A Fast and Flexible Static Site Generator built with
                 love by spf13 and friends in Go.
                 Complete documentation is available at http://hugo.spf13.com`,
-	Run: func(cmd *cobra.Command, args []string) {
-		// Do Stuff Here
-	},
+  Run: func(cmd *cobra.Command, args []string) {
+    // Do Stuff Here
+  },
 }
 ```
 
@@ -301,54 +294,54 @@ For example cmd/root.go:
 
 ```go
 import (
-	"fmt"
-	"os"
+  "fmt"
+  "os"
 
-	homedir "github.com/mitchellh/go-homedir"
-	"github.com/spf13/cobra"
-	"github.com/spf13/viper"
+  homedir "github.com/mitchellh/go-homedir"
+  "github.com/spf13/cobra"
+  "github.com/spf13/viper"
 )
 
 func init() {
-	cobra.OnInitialize(initConfig)
-	RootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra.yaml)")
-	RootCmd.PersistentFlags().StringVarP(&projectBase, "projectbase", "b", "", "base project directory eg. github.com/spf13/")
-	RootCmd.PersistentFlags().StringP("author", "a", "YOUR NAME", "Author name for copyright attribution")
-	RootCmd.PersistentFlags().StringVarP(&userLicense, "license", "l", "", "Name of license for the project (can provide `licensetext` in config)")
-	RootCmd.PersistentFlags().Bool("viper", true, "Use Viper for configuration")
-	viper.BindPFlag("author", RootCmd.PersistentFlags().Lookup("author"))
-	viper.BindPFlag("projectbase", RootCmd.PersistentFlags().Lookup("projectbase"))
-	viper.BindPFlag("useViper", RootCmd.PersistentFlags().Lookup("viper"))
-	viper.SetDefault("author", "NAME HERE <EMAIL ADDRESS>")
-	viper.SetDefault("license", "apache")
+  cobra.OnInitialize(initConfig)
+  RootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra.yaml)")
+  RootCmd.PersistentFlags().StringVarP(&projectBase, "projectbase", "b", "", "base project directory eg. github.com/spf13/")
+  RootCmd.PersistentFlags().StringP("author", "a", "YOUR NAME", "Author name for copyright attribution")
+  RootCmd.PersistentFlags().StringVarP(&userLicense, "license", "l", "", "Name of license for the project (can provide `licensetext` in config)")
+  RootCmd.PersistentFlags().Bool("viper", true, "Use Viper for configuration")
+  viper.BindPFlag("author", RootCmd.PersistentFlags().Lookup("author"))
+  viper.BindPFlag("projectbase", RootCmd.PersistentFlags().Lookup("projectbase"))
+  viper.BindPFlag("useViper", RootCmd.PersistentFlags().Lookup("viper"))
+  viper.SetDefault("author", "NAME HERE <EMAIL ADDRESS>")
+  viper.SetDefault("license", "apache")
 }
 
 func Execute() {
-	rootCmd.Execute()
+  RootCmd.Execute()
 }
 
-func main() {
+func initConfig() {
   // Don't forget to read config either from cfgFile or from home directory!
-	if cfgFile != "" {
-		// Use config file from the flag.
-		viper.SetConfigFile(cfgFile)
-	} else {
-		// Find home directory.
-		home, err := homedir.Dir()
-		if err != nil {
-			fmt.Println(home)
-			os.Exit(1)
-		}
-
-		// Search config in home directory with name ".cobra" (without extension).
-		viper.AddConfigPath(home)
-		viper.SetConfigName(".cobra")
-	}
-
-	if err := viper.ReadInConfig(); err != nil {
-		fmt.Println("Can't read config:", err)
-		os.Exit(1)
-	}
+  if cfgFile != "" {
+    // Use config file from the flag.
+    viper.SetConfigFile(cfgFile)
+  } else {
+    // Find home directory.
+    home, err := homedir.Dir()
+    if err != nil {
+      fmt.Println(err)
+      os.Exit(1)
+    }
+
+    // Search config in home directory with name ".cobra" (without extension).
+    viper.AddConfigPath(home)
+    viper.SetConfigName(".cobra")
+  }
+
+  if err := viper.ReadInConfig(); err != nil {
+    fmt.Println("Can't read config:", err)
+    os.Exit(1)
+  }
 }
 ```
 
@@ -363,17 +356,17 @@ In a Cobra app, typically the main.go file is very bare. It serves, one purpose,
 package main
 
 import (
-	"fmt"
-	"os"
+  "fmt"
+  "os"
 
-	"{pathToYourApp}/cmd"
+  "{pathToYourApp}/cmd"
 )
 
 func main() {
-	if err := cmd.RootCmd.Execute(); err != nil {
-		fmt.Println(err)
-		os.Exit(1)
-	}
+  if err := cmd.RootCmd.Execute(); err != nil {
+    fmt.Println(err)
+    os.Exit(1)
+  }
 }
 ```
 
@@ -389,21 +382,21 @@ populate it with the following:
 package cmd
 
 import (
-	"github.com/spf13/cobra"
-	"fmt"
+  "github.com/spf13/cobra"
+  "fmt"
 )
 
 func init() {
-	RootCmd.AddCommand(versionCmd)
+  RootCmd.AddCommand(versionCmd)
 }
 
 var versionCmd = &cobra.Command{
-	Use:   "version",
-	Short: "Print the version number of Hugo",
-	Long:  `All software has versions. This is Hugo's`,
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("Hugo Static Site Generator v0.9 -- HEAD")
-	},
+  Use:   "version",
+  Short: "Print the version number of Hugo",
+  Long:  `All software has versions. This is Hugo's`,
+  Run: func(cmd *cobra.Command, args []string) {
+    fmt.Println("Hugo Static Site Generator v0.9 -- HEAD")
+  },
 }
 ```
 
@@ -418,19 +411,6 @@ root, but commands can be attached at any level.
 RootCmd.AddCommand(versionCmd)
 ```
 
-### Remove a command from its parent
-
-Removing a command is not a common action in simple programs, but it allows 3rd
-parties to customize an existing command tree.
-
-In this example, we remove the existing `VersionCmd` command of an existing
-root command, and we replace it with our own version:
-
-```go
-mainlib.RootCmd.RemoveCommand(mainlib.VersionCmd)
-mainlib.RootCmd.AddCommand(versionCmd)
-```
-
 ## Working with Flags
 
 Flags provide modifiers to control how the action command operates.
@@ -473,8 +453,8 @@ You can also bind your flags with [viper](https://github.com/spf13/viper):
 var author string
 
 func init() {
-	RootCmd.PersistentFlags().StringVar(&author, "author", "YOUR NAME", "Author name for copyright attribution")
-	viper.BindPFlag("author", RootCmd.PersistentFlags().Lookup("author"))
+  RootCmd.PersistentFlags().StringVar(&author, "author", "YOUR NAME", "Author name for copyright attribution")
+  viper.BindPFlag("author", RootCmd.PersistentFlags().Lookup("author"))
 }
 ```
 
@@ -484,6 +464,41 @@ when the `--author` flag is not provided by user.
 
 More in [viper documentation](https://github.com/spf13/viper#working-with-flags).
 
+## Positional and Custom Arguments
+
+Validation of positional arguments can be specified using the `Args` field
+of `Command`.
+
+The following validators are built in:
+
+- `NoArgs` - the command will report an error if there are any positional args.
+- `ArbitraryArgs` - the command will accept any args.
+- `OnlyValidArgs` - the command will report an error if there are any positional args that are not in the `ValidArgs` field of `Command`.
+- `MinimumNArgs(int)` - the command will report an error if there are not at least N positional args.
+- `MaximumNArgs(int)` - the command will report an error if there are more than N positional args.
+- `ExactArgs(int)` - the command will report an error if there are not exactly N positional args.
+- `RangeArgs(min, max)` - the command will report an error if the number of args is not between the minimum and maximum number of expected args.
+
+An example of setting the custom validator:
+
+```go
+var cmd = &cobra.Command{
+  Short: "hello",
+  Args: func(cmd *cobra.Command, args []string) error {
+    if len(args) < 1 {
+      return errors.New("requires at least one arg")
+    }
+    if myapp.IsValidColor(args[0]) {
+      return nil
+    }
+    return fmt.Errorf("invalid color specified: %s", args[0])
+  },
+  Run: func(cmd *cobra.Command, args []string) {
+    fmt.Println("Hello, World!")
+  },
+}
+```
+
 ## Example
 
 In the example below, we have defined three commands. Two are at the top level
@@ -499,56 +514,56 @@ More documentation about flags is available at https://github.com/spf13/pflag
 package main
 
 import (
-	"fmt"
-	"strings"
+  "fmt"
+  "strings"
 
-	"github.com/spf13/cobra"
+  "github.com/spf13/cobra"
 )
 
 func main() {
-
-	var echoTimes int
-
-	var cmdPrint = &cobra.Command{
-		Use:   "print [string to print]",
-		Short: "Print anything to the screen",
-		Long: `print is for printing anything back to the screen.
-            For many years people have printed back to the screen.
-            `,
-		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Println("Print: " + strings.Join(args, " "))
-		},
-	}
-
-	var cmdEcho = &cobra.Command{
-		Use:   "echo [string to echo]",
-		Short: "Echo anything to the screen",
-		Long: `echo is for echoing anything back.
-            Echo works a lot like print, except it has a child command.
-            `,
-		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Println("Print: " + strings.Join(args, " "))
-		},
-	}
-
-	var cmdTimes = &cobra.Command{
-		Use:   "times [# times] [string to echo]",
-		Short: "Echo anything to the screen more times",
-		Long: `echo things multiple times back to the user by providing
-            a count and a string.`,
-		Run: func(cmd *cobra.Command, args []string) {
-			for i := 0; i < echoTimes; i++ {
-				fmt.Println("Echo: " + strings.Join(args, " "))
-			}
-		},
-	}
-
-	cmdTimes.Flags().IntVarP(&echoTimes, "times", "t", 1, "times to echo the input")
-
-	var rootCmd = &cobra.Command{Use: "app"}
-	rootCmd.AddCommand(cmdPrint, cmdEcho)
-	cmdEcho.AddCommand(cmdTimes)
-	rootCmd.Execute()
+  var echoTimes int
+
+  var cmdPrint = &cobra.Command{
+    Use:   "print [string to print]",
+    Short: "Print anything to the screen",
+    Long: `print is for printing anything back to the screen.
+For many years people have printed back to the screen.`,
+    Args: cobra.MinimumNArgs(1),
+    Run: func(cmd *cobra.Command, args []string) {
+      fmt.Println("Print: " + strings.Join(args, " "))
+    },
+  }
+
+  var cmdEcho = &cobra.Command{
+    Use:   "echo [string to echo]",
+    Short: "Echo anything to the screen",
+    Long: `echo is for echoing anything back.
+Echo works a lot like print, except it has a child command.`,
+    Args: cobra.MinimumNArgs(1),
+    Run: func(cmd *cobra.Command, args []string) {
+      fmt.Println("Print: " + strings.Join(args, " "))
+    },
+  }
+
+  var cmdTimes = &cobra.Command{
+    Use:   "times [# times] [string to echo]",
+    Short: "Echo anything to the screen more times",
+    Long: `echo things multiple times back to the user by providing
+a count and a string.`,
+    Args: cobra.MinimumNArgs(1),
+    Run: func(cmd *cobra.Command, args []string) {
+      for i := 0; i < echoTimes; i++ {
+        fmt.Println("Echo: " + strings.Join(args, " "))
+      }
+    },
+  }
+
+  cmdTimes.Flags().IntVarP(&echoTimes, "times", "t", 1, "times to echo the input")
+
+  var rootCmd = &cobra.Command{Use: "app"}
+  rootCmd.AddCommand(cmdPrint, cmdEcho)
+  cmdEcho.AddCommand(cmdTimes)
+  rootCmd.Execute()
 }
 ```
 
@@ -634,16 +649,16 @@ The default help command is
 
 ```go
 func (c *Command) initHelp() {
-	if c.helpCommand == nil {
-		c.helpCommand = &Command{
-			Use:   "help [command]",
-			Short: "Help about any command",
-			Long: `Help provides help for any command in the application.
+  if c.helpCommand == nil {
+    c.helpCommand = &Command{
+      Use:   "help [command]",
+      Short: "Help about any command",
+      Long: `Help provides help for any command in the application.
         Simply type ` + c.Name() + ` help [path to command] for full details.`,
-			Run: c.HelpFunc(),
-		}
-	}
-	c.AddCommand(c.helpCommand)
+      Run: c.HelpFunc(),
+    }
+  }
+  c.AddCommand(c.helpCommand)
 }
 ```
 
@@ -651,9 +666,7 @@ You can provide your own command, function or template through the following met
 
 ```go
 command.SetHelpCommand(cmd *Command)
-
 command.SetHelpFunc(f func(*Command, []string))
-
 command.SetHelpTemplate(s string)
 ```
 
@@ -719,8 +732,8 @@ The default usage function is:
 
 ```go
 return func(c *Command) error {
-	err := tmpl(c.Out(), c.UsageTemplate(), c)
-	return err
+  err := tmpl(c.Out(), c.UsageTemplate(), c)
+  return err
 }
 ```
 
@@ -748,57 +761,57 @@ An example of two commands which use all of these features is below.  When the s
 package main
 
 import (
-	"fmt"
+  "fmt"
 
-	"github.com/spf13/cobra"
+  "github.com/spf13/cobra"
 )
 
 func main() {
 
-	var rootCmd = &cobra.Command{
-		Use:   "root [sub]",
-		Short: "My root command",
-		PersistentPreRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside rootCmd PersistentPreRun with args: %v\n", args)
-		},
-		PreRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside rootCmd PreRun with args: %v\n", args)
-		},
-		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside rootCmd Run with args: %v\n", args)
-		},
-		PostRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside rootCmd PostRun with args: %v\n", args)
-		},
-		PersistentPostRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside rootCmd PersistentPostRun with args: %v\n", args)
-		},
-	}
-
-	var subCmd = &cobra.Command{
-		Use:   "sub [no options!]",
-		Short: "My subcommand",
-		PreRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside subCmd PreRun with args: %v\n", args)
-		},
-		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside subCmd Run with args: %v\n", args)
-		},
-		PostRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside subCmd PostRun with args: %v\n", args)
-		},
-		PersistentPostRun: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("Inside subCmd PersistentPostRun with args: %v\n", args)
-		},
-	}
-
-	rootCmd.AddCommand(subCmd)
-
-	rootCmd.SetArgs([]string{""})
-	_ = rootCmd.Execute()
-	fmt.Print("\n")
-	rootCmd.SetArgs([]string{"sub", "arg1", "arg2"})
-	_ = rootCmd.Execute()
+  var rootCmd = &cobra.Command{
+    Use:   "root [sub]",
+    Short: "My root command",
+    PersistentPreRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside rootCmd PersistentPreRun with args: %v\n", args)
+    },
+    PreRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside rootCmd PreRun with args: %v\n", args)
+    },
+    Run: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside rootCmd Run with args: %v\n", args)
+    },
+    PostRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside rootCmd PostRun with args: %v\n", args)
+    },
+    PersistentPostRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside rootCmd PersistentPostRun with args: %v\n", args)
+    },
+  }
+
+  var subCmd = &cobra.Command{
+    Use:   "sub [no options!]",
+    Short: "My subcommand",
+    PreRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside subCmd PreRun with args: %v\n", args)
+    },
+    Run: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside subCmd Run with args: %v\n", args)
+    },
+    PostRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside subCmd PostRun with args: %v\n", args)
+    },
+    PersistentPostRun: func(cmd *cobra.Command, args []string) {
+      fmt.Printf("Inside subCmd PersistentPostRun with args: %v\n", args)
+    },
+  }
+
+  rootCmd.AddCommand(subCmd)
+
+  rootCmd.SetArgs([]string{""})
+  rootCmd.Execute()
+  fmt.Println()
+  rootCmd.SetArgs([]string{"sub", "arg1", "arg2"})
+  rootCmd.Execute()
 }
 ```
 
@@ -824,28 +837,28 @@ command.
 package main
 
 import (
-	"errors"
-	"log"
+  "errors"
+  "log"
 
-	"github.com/spf13/cobra"
+  "github.com/spf13/cobra"
 )
 
 func main() {
-	var rootCmd = &cobra.Command{
-		Use:   "hugo",
-		Short: "Hugo is a very fast static site generator",
-		Long: `A Fast and Flexible Static Site Generator built with
-                love by spf13 and friends in Go.
-                Complete documentation is available at http://hugo.spf13.com`,
-		RunE: func(cmd *cobra.Command, args []string) error {
-			// Do Stuff Here
-			return errors.New("some random error")
-		},
-	}
-
-	if err := rootCmd.Execute(); err != nil {
-		log.Fatal(err)
-	}
+  var rootCmd = &cobra.Command{
+    Use:   "hugo",
+    Short: "Hugo is a very fast static site generator",
+    Long: `A Fast and Flexible Static Site Generator built with
+love by spf13 and friends in Go.
+Complete documentation is available at http://hugo.spf13.com`,
+    RunE: func(cmd *cobra.Command, args []string) error {
+      // Do Stuff Here
+      return errors.New("some random error")
+    },
+  }
+
+  if err := rootCmd.Execute(); err != nil {
+    log.Fatal(err)
+  }
 }
 ```
 
@@ -901,16 +914,6 @@ Cobra can generate a man page based on the subcommands, flags, etc. A simple exa
 
 Cobra can generate a bash-completion file. If you add more information to your command, these completions can be amazingly powerful and flexible.  Read more about it in [Bash Completions](bash_completions.md).
 
-## Debugging
-
-Cobra provides a ‘DebugFlags’ method on a command which, when called, will print
-out everything Cobra knows about the flags for each command.
-
-### Example
-
-```go
-command.DebugFlags()
-```
 
 ## Extensions
 
diff --git a/vendor/github.com/spf13/cobra/args.go b/vendor/github.com/spf13/cobra/args.go
new file mode 100644
index 00000000..94a6ca27
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/args.go
@@ -0,0 +1,98 @@
+package cobra
+
+import (
+	"fmt"
+)
+
+type PositionalArgs func(cmd *Command, args []string) error
+
+// Legacy arg validation has the following behaviour:
+// - root commands with no subcommands can take arbitrary arguments
+// - root commands with subcommands will do subcommand validity checking
+// - subcommands will always accept arbitrary arguments
+func legacyArgs(cmd *Command, args []string) error {
+	// no subcommand, always take args
+	if !cmd.HasSubCommands() {
+		return nil
+	}
+
+	// root command with subcommands, do subcommand checking
+	if !cmd.HasParent() && len(args) > 0 {
+		return fmt.Errorf("unknown command %q for %q%s", args[0], cmd.CommandPath(), cmd.findSuggestions(args[0]))
+	}
+	return nil
+}
+
+// NoArgs returns an error if any args are included
+func NoArgs(cmd *Command, args []string) error {
+	if len(args) > 0 {
+		return fmt.Errorf("unknown command %q for %q", args[0], cmd.CommandPath())
+	}
+	return nil
+}
+
+// OnlyValidArgs returns an error if any args are not in the list of ValidArgs
+func OnlyValidArgs(cmd *Command, args []string) error {
+	if len(cmd.ValidArgs) > 0 {
+		for _, v := range args {
+			if !stringInSlice(v, cmd.ValidArgs) {
+				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.findSuggestions(args[0]))
+			}
+		}
+	}
+	return nil
+}
+
+func stringInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
+// ArbitraryArgs never returns an error
+func ArbitraryArgs(cmd *Command, args []string) error {
+	return nil
+}
+
+// MinimumNArgs returns an error if there is not at least N args
+func MinimumNArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) < n {
+			return fmt.Errorf("requires at least %d arg(s), only received %d", n, len(args))
+		}
+		return nil
+	}
+}
+
+// MaximumNArgs returns an error if there are more than N args
+func MaximumNArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) > n {
+			return fmt.Errorf("accepts at most %d arg(s), received %d", n, len(args))
+		}
+		return nil
+	}
+}
+
+// ExactArgs returns an error if there are not exactly n args
+func ExactArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) != n {
+			return fmt.Errorf("accepts %d arg(s), received %d", n, len(args))
+		}
+		return nil
+	}
+}
+
+// RangeArgs returns an error if the number of args is not within the expected range
+func RangeArgs(min int, max int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) < min || len(args) > max {
+			return fmt.Errorf("accepts between %d and %d arg(s), received %d", min, max, len(args))
+		}
+		return nil
+	}
+}
diff --git a/vendor/github.com/spf13/cobra/bash_completions.go b/vendor/github.com/spf13/cobra/bash_completions.go
index e0cfb349..e402065d 100644
--- a/vendor/github.com/spf13/cobra/bash_completions.go
+++ b/vendor/github.com/spf13/cobra/bash_completions.go
@@ -463,14 +463,14 @@ func gen(buf *bytes.Buffer, cmd *Command) {
 }
 
 // GenBashCompletion generates bash completion file and writes to the passed writer.
-func (cmd *Command) GenBashCompletion(w io.Writer) error {
+func (c *Command) GenBashCompletion(w io.Writer) error {
 	buf := new(bytes.Buffer)
-	writePreamble(buf, cmd.Name())
-	if len(cmd.BashCompletionFunction) > 0 {
-		buf.WriteString(cmd.BashCompletionFunction + "\n")
+	writePreamble(buf, c.Name())
+	if len(c.BashCompletionFunction) > 0 {
+		buf.WriteString(c.BashCompletionFunction + "\n")
 	}
-	gen(buf, cmd)
-	writePostscript(buf, cmd.Name())
+	gen(buf, c)
+	writePostscript(buf, c.Name())
 
 	_, err := buf.WriteTo(w)
 	return err
@@ -481,24 +481,24 @@ func nonCompletableFlag(flag *pflag.Flag) bool {
 }
 
 // GenBashCompletionFile generates bash completion file.
-func (cmd *Command) GenBashCompletionFile(filename string) error {
+func (c *Command) GenBashCompletionFile(filename string) error {
 	outFile, err := os.Create(filename)
 	if err != nil {
 		return err
 	}
 	defer outFile.Close()
 
-	return cmd.GenBashCompletion(outFile)
+	return c.GenBashCompletion(outFile)
 }
 
 // MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag, if it exists.
-func (cmd *Command) MarkFlagRequired(name string) error {
-	return MarkFlagRequired(cmd.Flags(), name)
+func (c *Command) MarkFlagRequired(name string) error {
+	return MarkFlagRequired(c.Flags(), name)
 }
 
 // MarkPersistentFlagRequired adds the BashCompOneRequiredFlag annotation to the named persistent flag, if it exists.
-func (cmd *Command) MarkPersistentFlagRequired(name string) error {
-	return MarkFlagRequired(cmd.PersistentFlags(), name)
+func (c *Command) MarkPersistentFlagRequired(name string) error {
+	return MarkFlagRequired(c.PersistentFlags(), name)
 }
 
 // MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag in the flag set, if it exists.
@@ -508,20 +508,20 @@ func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
 
 // MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag, if it exists.
 // Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func (cmd *Command) MarkFlagFilename(name string, extensions ...string) error {
-	return MarkFlagFilename(cmd.Flags(), name, extensions...)
+func (c *Command) MarkFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.Flags(), name, extensions...)
 }
 
 // MarkFlagCustom adds the BashCompCustom annotation to the named flag, if it exists.
 // Generated bash autocompletion will call the bash function f for the flag.
-func (cmd *Command) MarkFlagCustom(name string, f string) error {
-	return MarkFlagCustom(cmd.Flags(), name, f)
+func (c *Command) MarkFlagCustom(name string, f string) error {
+	return MarkFlagCustom(c.Flags(), name, f)
 }
 
 // MarkPersistentFlagFilename adds the BashCompFilenameExt annotation to the named persistent flag, if it exists.
 // Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func (cmd *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
-	return MarkFlagFilename(cmd.PersistentFlags(), name, extensions...)
+func (c *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.PersistentFlags(), name, extensions...)
 }
 
 // MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag in the flag set, if it exists.
diff --git a/vendor/github.com/spf13/cobra/cobra.go b/vendor/github.com/spf13/cobra/cobra.go
index 2726d19e..8928cefc 100644
--- a/vendor/github.com/spf13/cobra/cobra.go
+++ b/vendor/github.com/spf13/cobra/cobra.go
@@ -47,6 +47,15 @@ var EnablePrefixMatching = false
 // To disable sorting, set it to false.
 var EnableCommandSorting = true
 
+// MousetrapHelpText enables an information splash screen on Windows
+// if the CLI is started from explorer.exe.
+// To disable the mousetrap, just set this variable to blank string ("").
+// Works only on Microsoft Windows.
+var MousetrapHelpText string = `This is a command line tool.
+
+You need to open cmd.exe and run it from there.
+`
+
 // AddTemplateFunc adds a template function that's available to Usage and Help
 // template generation.
 func AddTemplateFunc(name string, tmplFunc interface{}) {
diff --git a/vendor/github.com/spf13/cobra/command.go b/vendor/github.com/spf13/cobra/command.go
index e85bf51a..185e4526 100644
--- a/vendor/github.com/spf13/cobra/command.go
+++ b/vendor/github.com/spf13/cobra/command.go
@@ -54,6 +54,9 @@ type Command struct {
 	// ValidArgs is list of all valid non-flag arguments that are accepted in bash completions
 	ValidArgs []string
 
+	// Expected arguments
+	Args PositionalArgs
+
 	// ArgAliases is List of aliases for ValidArgs.
 	// These are not suggested to the user in the bash completion,
 	// but accepted if entered manually.
@@ -513,31 +516,27 @@ func (c *Command) Find(args []string) (*Command, []string, error) {
 	}
 
 	commandFound, a := innerfind(c, args)
-	argsWOflags := stripFlags(a, commandFound)
-
-	// no subcommand, always take args
-	if !commandFound.HasSubCommands() {
-		return commandFound, a, nil
+	if commandFound.Args == nil {
+		return commandFound, a, legacyArgs(commandFound, stripFlags(a, commandFound))
 	}
+	return commandFound, a, nil
+}
 
-	// root command with subcommands, do subcommand checking
-	if commandFound == c && len(argsWOflags) > 0 {
-		suggestionsString := ""
-		if !c.DisableSuggestions {
-			if c.SuggestionsMinimumDistance <= 0 {
-				c.SuggestionsMinimumDistance = 2
-			}
-			if suggestions := c.SuggestionsFor(argsWOflags[0]); len(suggestions) > 0 {
-				suggestionsString += "\n\nDid you mean this?\n"
-				for _, s := range suggestions {
-					suggestionsString += fmt.Sprintf("\t%v\n", s)
-				}
-			}
+func (c *Command) findSuggestions(arg string) string {
+	if c.DisableSuggestions {
+		return ""
+	}
+	if c.SuggestionsMinimumDistance <= 0 {
+		c.SuggestionsMinimumDistance = 2
+	}
+	suggestionsString := ""
+	if suggestions := c.SuggestionsFor(arg); len(suggestions) > 0 {
+		suggestionsString += "\n\nDid you mean this?\n"
+		for _, s := range suggestions {
+			suggestionsString += fmt.Sprintf("\t%v\n", s)
 		}
-		return commandFound, a, fmt.Errorf("unknown command %q for %q%s", argsWOflags[0], commandFound.CommandPath(), suggestionsString)
 	}
-
-	return commandFound, a, nil
+	return suggestionsString
 }
 
 // SuggestionsFor provides suggestions for the typedName.
@@ -624,6 +623,10 @@ func (c *Command) execute(a []string) (err error) {
 		argWoFlags = a
 	}
 
+	if err := c.ValidateArgs(argWoFlags); err != nil {
+		return err
+	}
+
 	for p := c; p != nil; p = p.Parent() {
 		if p.PersistentPreRunE != nil {
 			if err := p.PersistentPreRunE(c, argWoFlags); err != nil {
@@ -747,6 +750,13 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 	return cmd, err
 }
 
+func (c *Command) ValidateArgs(args []string) error {
+	if c.Args == nil {
+		return nil
+	}
+	return c.Args(c, args)
+}
+
 // InitDefaultHelpFlag adds default help flag to c.
 // It is called automatically by executing the c or by calling help and usage.
 // If c already has help flag, it will do nothing.
@@ -767,28 +777,28 @@ func (c *Command) InitDefaultHelpFlag() {
 // It is called automatically by executing the c or by calling help and usage.
 // If c already has help command or c has no subcommands, it will do nothing.
 func (c *Command) InitDefaultHelpCmd() {
-	if c.helpCommand != nil || !c.HasSubCommands() {
+	if !c.HasSubCommands() {
 		return
 	}
 
-	c.helpCommand = &Command{
-		Use:   "help [command]",
-		Short: "Help about any command",
-		Long: `Help provides help for any command in the application.
-    Simply type ` + c.Name() + ` help [path to command] for full details.`,
-		PersistentPreRun:  func(cmd *Command, args []string) {},
-		PersistentPostRun: func(cmd *Command, args []string) {},
+	if c.helpCommand == nil {
+		c.helpCommand = &Command{
+			Use:   "help [command]",
+			Short: "Help about any command",
+			Long: `Help provides help for any command in the application.
+Simply type ` + c.Name() + ` help [path to command] for full details.`,
 
-		Run: func(c *Command, args []string) {
-			cmd, _, e := c.Root().Find(args)
-			if cmd == nil || e != nil {
-				c.Printf("Unknown help topic %#q\n", args)
-				c.Root().Usage()
-			} else {
-				cmd.InitDefaultHelpFlag() // make possible 'help' flag to be shown
-				cmd.Help()
-			}
-		},
+			Run: func(c *Command, args []string) {
+				cmd, _, e := c.Root().Find(args)
+				if cmd == nil || e != nil {
+					c.Printf("Unknown help topic %#q\n", args)
+					c.Root().Usage()
+				} else {
+					cmd.InitDefaultHelpFlag() // make possible 'help' flag to be shown
+					cmd.Help()
+				}
+			},
+		}
 	}
 	c.RemoveCommand(c.helpCommand)
 	c.AddCommand(c.helpCommand)
@@ -1249,13 +1259,20 @@ func (c *Command) persistentFlag(name string) (flag *flag.Flag) {
 }
 
 // ParseFlags parses persistent flag tree and local flags.
-func (c *Command) ParseFlags(args []string) (err error) {
+func (c *Command) ParseFlags(args []string) error {
 	if c.DisableFlagParsing {
 		return nil
 	}
+
+	beforeErrorBufLen := c.flagErrorBuf.Len()
 	c.mergePersistentFlags()
-	err = c.Flags().Parse(args)
-	return
+	err := c.Flags().Parse(args)
+	// Print warnings if they occurred (e.g. deprecated flag messages).
+	if c.flagErrorBuf.Len()-beforeErrorBufLen > 0 && err == nil {
+		c.Print(c.flagErrorBuf.String())
+	}
+
+	return err
 }
 
 // Parent returns a commands parent command.
diff --git a/vendor/github.com/spf13/cobra/command_win.go b/vendor/github.com/spf13/cobra/command_win.go
index 4b0eaa1b..edec728e 100644
--- a/vendor/github.com/spf13/cobra/command_win.go
+++ b/vendor/github.com/spf13/cobra/command_win.go
@@ -11,14 +11,8 @@ import (
 
 var preExecHookFn = preExecHook
 
-// enables an information splash screen on Windows if the CLI is started from explorer.exe.
-var MousetrapHelpText string = `This is a command line tool
-
-You need to open cmd.exe and run it from there.
-`
-
 func preExecHook(c *Command) {
-	if mousetrap.StartedByExplorer() {
+	if MousetrapHelpText != "" && mousetrap.StartedByExplorer() {
 		c.Print(MousetrapHelpText)
 		time.Sleep(5 * time.Second)
 		os.Exit(1)
diff --git a/vendor/github.com/spf13/pflag/flag.go b/vendor/github.com/spf13/pflag/flag.go
index 6f1fc300..7b84e2cd 100644
--- a/vendor/github.com/spf13/pflag/flag.go
+++ b/vendor/github.com/spf13/pflag/flag.go
@@ -556,6 +556,10 @@ func UnquoteUsage(flag *Flag) (name string, usage string) {
 		name = "int"
 	case "uint64":
 		name = "uint"
+	case "stringSlice":
+		name = "strings"
+	case "intSlice":
+		name = "ints"
 	}
 
 	return