Update cobra and pflag

Signed-off-by: Lantao Liu <lantaol@google.com>
2017-10-26 05:57:29 +00:00 · 2017-10-26 05:57:29 +00:00 · c6fd18ddc3
commit c6fd18ddc3
parent 1d5cd86207
14 changed files with 1564 additions and 1231 deletions
--- a/vendor.conf
+++ b/vendor.conf
@ -49,8 +49,8 @@ github.com/PuerkitoBio/purell v1.0.0
 github.com/PuerkitoBio/urlesc 5bd2802263f21d8788851d5305584c82a5c75d7e
 github.com/seccomp/libseccomp-golang 32f571b70023028bd57d9288c20efbcb237f3ce0 
 github.com/sirupsen/logrus v1.0.0
-github.com/spf13/cobra f62e98d28ab7ad31d707ba837a966378465c7b57
-github.com/spf13/pflag 9ff6c6923cfffbcd502984b8e0c80539a94968b7
+github.com/spf13/cobra v0.0.1
+github.com/spf13/pflag v1.0.0
 github.com/stretchr/testify v1.1.4
 github.com/syndtr/gocapability e7cb7fa329f456b3855136a2642b197bad7366ba
 github.com/tchap/go-patricia 5ad6cdb7538b0097d5598c7e57f0a24072adf7dc
--- a/vendor/github.com/docker/docker/hack/README.md
+++ b/vendor/github.com/docker/docker/hack/README.md
@ -0,0 +1,60 @@
+## About
+
+This directory contains a collection of scripts used to build and manage this
+repository. If there are any issues regarding the intention of a particular
+script (or even part of a certain script), please reach out to us.
+It may help us either refine our current scripts, or add on new ones
+that are appropriate for a given use case.
+
+## DinD (dind.sh)
+
+DinD is a wrapper script which allows Docker to be run inside a Docker
+container. DinD requires the container to
+be run with privileged mode enabled.
+
+## Generate Authors (generate-authors.sh)
+
+Generates AUTHORS; a file with all the names and corresponding emails of
+individual contributors. AUTHORS can be found in the home directory of
+this repository.
+
+## Make
+
+There are two make files, each with different extensions. Neither are supposed
+to be called directly; only invoke `make`. Both scripts run inside a Docker
+container.
+
+### make.ps1
+
+- The Windows native build script that uses PowerShell semantics; it is limited
+unlike `hack\make.sh` since it does not provide support for the full set of
+operations provided by the Linux counterpart, `make.sh`. However, `make.ps1`
+does provide support for local Windows development and Windows to Windows CI.
+More information is found within `make.ps1` by the author, @jhowardmsft
+
+### make.sh
+
+- Referenced via `make test` when running tests on a local machine,
+or directly referenced when running tests inside a Docker development container.  
+- When running on a local machine, `make test` to run all tests found in
+`test`, `test-unit`, `test-integration`, and `test-docker-py` on
+your local machine. The default timeout is set in `make.sh` to 60 minutes
+(`${TIMEOUT:=60m}`), since it currently takes up to an hour to run
+all of the tests.
+- When running inside a Docker development container, `hack/make.sh` does
+not have a single target that runs all the tests. You need to provide a
+single command line with multiple targets that performs the same thing.
+An example referenced from [Run targets inside a development container](https://docs.docker.com/opensource/project/test-and-docs/#run-targets-inside-a-development-container): `root@5f8630b873fe:/go/src/github.com/moby/moby# hack/make.sh dynbinary binary cross test-unit test-integration test-docker-py`
+- For more information related to testing outside the scope of this README,
+refer to
+[Run tests and test documentation](https://docs.docker.com/opensource/project/test-and-docs/)
+
+## Release (release.sh)
+
+Releases any bundles built by `make` on a public AWS S3 bucket.
+For information regarding configuration, please view `release.sh`.
+
+## Vendor (vendor.sh)
+
+A shell script that is a wrapper around Vndr. For information on how to use
+this, please refer to [vndr's README](https://github.com/LK4D4/vndr/blob/master/README.md)
--- a/vendor/github.com/docker/docker/hack/integration-cli-on-swarm/README.md
+++ b/vendor/github.com/docker/docker/hack/integration-cli-on-swarm/README.md
@ -0,0 +1,69 @@
+# Integration Testing on Swarm
+
+IT on Swarm allows you to execute integration test in parallel across a Docker Swarm cluster
+
+## Architecture
+
+### Master service
+
+  - Works as a funker caller
+  - Calls a worker funker (`-worker-service`) with a chunk of `-check.f` filter strings (passed as a file via `-input` flag, typically `/mnt/input`)
+
+### Worker service
+
+  - Works as a funker callee
+  - Executes an equivalent of `TESTFLAGS=-check.f TestFoo|TestBar|TestBaz ... make test-integration-cli` using the bind-mounted API socket (`docker.sock`)
+
+### Client
+
+  - Controls master and workers via `docker stack`
+  - No need to have a local daemon
+
+Typically, the master and workers are supposed to be running on a cloud environment,
+while the client is supposed to be running on a laptop, e.g. Docker for Mac/Windows.
+
+## Requirement
+
+  - Docker daemon 1.13 or later
+  - Private registry for distributed execution with multiple nodes
+
+## Usage
+
+### Step 1: Prepare images
+
+    $ make build-integration-cli-on-swarm
+
+Following environment variables are known to work in this step:
+
+ - `BUILDFLAGS`
+ - `DOCKER_INCREMENTAL_BINARY`
+
+Note: during the transition into Moby Project, you might need to create a symbolic link `$GOPATH/src/github.com/docker/docker` to `$GOPATH/src/github.com/moby/moby`. 
+
+### Step 2: Execute tests
+
+    $ ./hack/integration-cli-on-swarm/integration-cli-on-swarm -replicas 40 -push-worker-image YOUR_REGISTRY.EXAMPLE.COM/integration-cli-worker:latest 
+
+Following environment variables are known to work in this step:
+
+ - `DOCKER_GRAPHDRIVER`
+ - `DOCKER_EXPERIMENTAL`
+
+#### Flags
+
+Basic flags:
+
+ - `-replicas N`: the number of worker service replicas. i.e. degree of parallelism.
+ - `-chunks N`: the number of chunks. By default, `chunks` == `replicas`.
+ - `-push-worker-image REGISTRY/IMAGE:TAG`: push the worker image to the registry. Note that if you have only single node and hence you do not need a private registry, you do not need to specify `-push-worker-image`.
+
+Experimental flags for mitigating makespan nonuniformity:
+
+ - `-shuffle`: Shuffle the test filter strings
+
+Flags for debugging IT on Swarm itself:
+
+ - `-rand-seed N`: the random seed. This flag is useful for deterministic replaying. By default(0), the timestamp is used.
+ - `-filters-file FILE`: the file contains `-check.f` strings. By default, the file is automatically generated.
+ - `-dry-run`: skip the actual workload
+ - `keep-executor`: do not auto-remove executor containers, which is used for running privileged programs on Swarm
--- a/vendor/github.com/docker/docker/hack/integration-cli-on-swarm/agent/vendor.conf
+++ b/vendor/github.com/docker/docker/hack/integration-cli-on-swarm/agent/vendor.conf
@ -0,0 +1,2 @@
+# dependencies specific to worker (i.e. github.com/docker/docker/...) are not vendored here
+github.com/bfirsh/funker-go eaa0a2e06f30e72c9a0b7f858951e581e26ef773
--- a/vendor/github.com/spf13/cobra/README.md
+++ b/vendor/github.com/spf13/cobra/README.md
@ -8,6 +8,7 @@ Many of the most widely used Go projects are built using Cobra including:
 * [Hugo](http://gohugo.io)
 * [rkt](https://github.com/coreos/rkt)
 * [etcd](https://github.com/coreos/etcd)
+* [Moby (former Docker)](https://github.com/moby/moby)
 * [Docker (distribution)](https://github.com/docker/distribution)
 * [OpenShift](https://www.openshift.com/)
 * [Delve](https://github.com/derekparker/delve)
@ -15,16 +16,36 @@ Many of the most widely used Go projects are built using Cobra including:
 * [CockroachDB](http://www.cockroachlabs.com/)
 * [Bleve](http://www.blevesearch.com/)
 * [ProjectAtomic (enterprise)](http://www.projectatomic.io/)
-* [Parse (CLI)](https://parse.com/)
 * [GiantSwarm's swarm](https://github.com/giantswarm/cli)
 * [Nanobox](https://github.com/nanobox-io/nanobox)/[Nanopack](https://github.com/nanopack)
-
+* [rclone](http://rclone.org/)
+* [nehm](https://github.com/bogem/nehm)

 [![Build Status](https://travis-ci.org/spf13/cobra.svg "Travis CI status")](https://travis-ci.org/spf13/cobra)
 [![CircleCI status](https://circleci.com/gh/spf13/cobra.png?circle-token=:circle-token "CircleCI status")](https://circleci.com/gh/spf13/cobra)
 [![GoDoc](https://godoc.org/github.com/spf13/cobra?status.svg)](https://godoc.org/github.com/spf13/cobra)

-![cobra](https://cloud.githubusercontent.com/assets/173412/10911369/84832a8e-8212-11e5-9f82-cc96660a4794.gif)
+# Table of Contents
+
+- [Overview](#overview)
+- [Concepts](#concepts)
+  * [Commands](#commands)
+  * [Flags](#flags)
+- [Installing](#installing)
+- [Getting Started](#getting-started)
+  * [Using the Cobra Generator](#using-the-cobra-generator)
+  * [Using the Cobra Library](#using-the-cobra-library)
+  * [Working with Flags](#working-with-flags)
+  * [Positional and Custom Arguments](#positional-and-custom-arguments)
+  * [Example](#example)
+  * [Help Command](#help-command)
+  * [Usage Message](#usage-message)
+  * [PreRun and PostRun Hooks](#prerun-and-postrun-hooks)
+  * [Suggestions when "unknown command" happens](#suggestions-when-unknown-command-happens)
+  * [Generating documentation for your command](#generating-documentation-for-your-command)
+  * [Generating bash completions](#generating-bash-completions)
+- [Contributing](#contributing)
+- [License](#license)

 # Overview

@ -39,27 +60,16 @@ Cobra provides:
 * Fully POSIX-compliant flags (including short & long versions)
 * Nested subcommands
 * Global, local and cascading flags
-* Easy generation of applications & commands with `cobra create appname` & `cobra add cmdname`
+* Easy generation of applications & commands with `cobra init appname` & `cobra add cmdname`
 * Intelligent suggestions (`app srver`... did you mean `app server`?)
 * Automatic help generation for commands and flags
-* Automatic detailed help for `app help [command]`
 * Automatic help flag recognition of `-h`, `--help`, etc.
 * Automatically generated bash autocomplete for your application
 * Automatically generated man pages for your application
 * Command aliases so you can change things without breaking them
-* The flexibilty to define your own help, usage, etc.
+* The flexibility to define your own help, usage, etc.
 * Optional tight integration with [viper](http://github.com/spf13/viper) for 12-factor apps

-Cobra has an exceptionally clean interface and simple design without needless
-constructors or initialization methods.
-
-Applications built with Cobra commands are designed to be as user-friendly as
-possible. Flags can be placed before or after the command (as long as a
-confusing space isn’t provided). Both short and long flags can be used. A
-command need not even be fully typed.  Help is automatically generated and
-available for the application or for a specific command using either the help
-command or the `--help` flag.
-
 # Concepts

 Cobra is built on a structure of commands, arguments & flags.
@ -78,11 +88,11 @@ A few good real world examples may better illustrate this point.

 In the following example, 'server' is a command, and 'port' is a flag:

-    > hugo server --port=1313
+    hugo server --port=1313

 In this command we are telling Git to clone the url bare.

-    > git clone URL --bare
+    git clone URL --bare

 ## Commands

@ -92,20 +102,11 @@ have children commands and optionally run an action.

 In the example above, 'server' is the command.

-A Command has the following structure:
-
-```go
-type Command struct {
-    Use string // The one-line usage message.
-    Short string // The short description shown in the 'help' output.
-    Long string // The long message shown in the 'help <this-command>' output.
-    Run func(cmd *Command, args []string) // Run runs the command.
-}
-```
+[More about cobra.Command](https://godoc.org/github.com/spf13/cobra#Command)

 ## Flags

-A Flag is a way to modify the behavior of a command. Cobra supports
+A flag is a way to modify the behavior of a command. Cobra supports
 fully POSIX-compliant flags as well as the Go [flag package](https://golang.org/pkg/flag/).
 A Cobra command can define flags that persist through to children commands
 and flags that are only available to that command.
@ -113,23 +114,15 @@ and flags that are only available to that command.
 In the example above, 'port' is the flag.

 Flag functionality is provided by the [pflag
-library](https://github.com/ogier/pflag), a fork of the flag standard library
+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 executible
-along with the library:
+of the library. This command will install the `cobra` generator executable
+along with the library and its dependencies:

-    > go get -v github.com/spf13/cobra/cobra
+    go get -u github.com/spf13/cobra/cobra

 Next, include Cobra in your application:

@ -139,8 +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/
@ -152,17 +145,22 @@ 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 "{pathToYourApp}/cmd"
+import (
+  "fmt"
+  "os"
+
+  "{pathToYourApp}/cmd"
+)

 func main() {
  if err := cmd.RootCmd.Execute(); err != nil {
    fmt.Println(err)
-		os.Exit(-1)
+    os.Exit(1)
  }
 }
 ```
@ -172,99 +170,14 @@ func main() {
 Cobra provides its own program that will create your application and add any
 commands you want. It's the easiest way to incorporate Cobra into your application.

-In order to use the cobra command, compile it using the following command:
+[Here](https://github.com/spf13/cobra/blob/master/cobra/README.md) you can find more information about it.

-    > go install github.com/spf13/cobra/cobra
+## Using the Cobra Library

-This will create the cobra executable under your go path bin directory!
-
-### cobra init
-
-The `cobra init [yourApp]` command will create your initial application code
-for you. It is a very powerful application that will populate your program with
-the right structure so you can immediately enjoy all the benefits of Cobra. It
-will also automatically apply the license you specify to your application.
-
-Cobra init is pretty smart. You can provide it a full path, or simply a path
-similar to what is expected in the import.
-
-```
-cobra init github.com/spf13/newAppName
-```
-
-### cobra add
-
-Once an application is initialized Cobra can create additional commands for you.
-Let's say you created an app and you wanted the following commands for it:
-
-* app serve
-* app config
-* app config create
-
-In your project directory (where your main.go file is) you would run the following:
-
-```
-cobra add serve
-cobra add config
-cobra add create -p 'configCmd'
-```
-
-Once you have run these three commands you would have an app structure that would look like:
-
-```
-  ▾ app/
-    ▾ cmd/
-        serve.go
-        config.go
-        create.go
-      main.go
-```
-
-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.
-
-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
-file which will help you eliminate providing a bunch of repeated information in
-flags over and over.
-
-An example ~/.cobra.yaml file:
-
-```yaml
-author: Steve Francia <spf@spf13.com>
-license: MIT
-```
-
-You can specify no license by setting `license` to `none` or you can specify
-a custom license:
-
-```yaml
-license:
-  header: This file is part of {{ .appName }}.
-  text: |
-    {{ .copyright }}
-
-    This is my license. There are many like it, but this one is mine.
-    My license is my best friend. It is my life. I must master it as I must
-    master my life.  
-```
-
-## 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
-
-The root command represents your binary itself.
-
-
-#### Manually create rootCmd
+### Create rootCmd

 Cobra doesn't require any special constructors. Simply create your commands.

@ -285,9 +198,18 @@ var RootCmd = &cobra.Command{

 You will additionally define flags and handle configuration in your init() function.

-for example cmd/root.go:
+For example cmd/root.go:

 ```go
+import (
+  "fmt"
+  "os"
+
+  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)")
@ -301,6 +223,34 @@ func init() {
  viper.SetDefault("author", "NAME HERE <EMAIL ADDRESS>")
  viper.SetDefault("license", "apache")
 }
+
+func Execute() {
+  RootCmd.Execute()
+}
+
+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(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)
+  }
+}
 ```

 ### Create your main.go
@ -313,17 +263,21 @@ In a Cobra app, typically the main.go file is very bare. It serves, one purpose,
 ```go
 package main

-import "{pathToYourApp}/cmd"
+import (
+  "fmt"
+  "os"
+
+  "{pathToYourApp}/cmd"
+)

 func main() {
  if err := cmd.RootCmd.Execute(); err != nil {
    fmt.Println(err)
-		os.Exit(-1)
+    os.Exit(1)
  }
 }
 ```

-
 ### Create additional commands

 Additional commands can be defined and typically are each given their own file
@ -337,6 +291,7 @@ package cmd

 import (
  "github.com/spf13/cobra"
+  "fmt"
 )

 func init() {
@ -353,30 +308,6 @@ var versionCmd = &cobra.Command{
 }
 ```

-### Attach command to its parent
-
-
-If you notice in the above example we attach the command to its parent. In
-this case the parent is the rootCmd. In this example we are attaching it to the
-root, but commands can be attached at any level.
-
-```go
-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.
@ -412,6 +343,71 @@ A flag can also be assigned locally which will only apply to that specific comma
 RootCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from")
 ```

+### Local Flag on Parent Commands
+
+By default Cobra only parses local flags on the target command, any local flags on 
+parent commands are ignored. By enabling `Command.TraverseChildren` Cobra will 
+parse local flags on each command before executing the target command.
+
+```go
+command := cobra.Command{
+  Use: "print [OPTIONS] [COMMANDS]",
+  TraverseChildren: true,
+}
+```
+
+### Bind Flags with Config
+
+You can also bind your flags with [viper](https://github.com/spf13/viper):
+```go
+var author string
+
+func init() {
+  RootCmd.PersistentFlags().StringVar(&author, "author", "YOUR NAME", "Author name for copyright attribution")
+  viper.BindPFlag("author", RootCmd.PersistentFlags().Lookup("author"))
+}
+```
+
+In this example the persistent flag `author` is bound with `viper`.
+**Note**, that the variable `author` will not be set to the value from config,
+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

@ -435,15 +431,14 @@ import (
 )

 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.
-            `,
+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, " "))
    },
@ -453,8 +448,8 @@ func main() {
    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.
-            `,
+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, " "))
    },
@ -465,6 +460,7 @@ func main() {
    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, " "))
@ -483,7 +479,7 @@ func main() {

 For a more complete example of a larger application, please checkout [Hugo](http://gohugo.io/).

-## The Help Command
+## Help Command

 Cobra automatically adds a help command to your application when you have subcommands.
 This will be called when a user runs 'app help'. Additionally, help will also
@ -496,60 +492,28 @@ create' is called.  Every command will automatically have the '--help' flag adde
 The following output is automatically generated by Cobra. Nothing beyond the
 command and flag definitions are needed.

-    > hugo help
+    $ cobra help

-    hugo is the main command, used to build your Hugo site.
-
-    Hugo is a Fast and Flexible Static Site Generator
-    built with love by spf13 and friends in Go.
-
-    Complete documentation is available at http://gohugo.io/.
+    Cobra is a CLI library for Go that empowers applications.
+    This application is a tool to generate the needed files
+    to quickly create a Cobra application.

    Usage:
-      hugo [flags]
-      hugo [command]
+      cobra [command]

    Available Commands:
-      server          Hugo runs its own webserver to render the files
-      version         Print the version number of Hugo
-      config          Print the site configuration
-      check           Check content in the source directory
-      benchmark       Benchmark hugo by building a site a number of times.
-      convert         Convert your content to different formats
-      new             Create new content for your site
-      list            Listing out various types of content
-      undraft         Undraft changes the content's draft status from 'True' to 'False'
-      genautocomplete Generate shell autocompletion script for Hugo
-      gendoc          Generate Markdown documentation for the Hugo CLI.
-      genman          Generate man page for Hugo
-      import          Import your site from others.
+      add         Add a command to a Cobra Application
+      help        Help about any command
+      init        Initialize a Cobra Application

    Flags:
-      -b, --baseURL="": hostname (and path) to the root, e.g. http://spf13.com/
-      -D, --buildDrafts[=false]: include content marked as draft
-      -F, --buildFuture[=false]: include content with publishdate in the future
-          --cacheDir="": filesystem path to cache directory. Defaults: $TMPDIR/hugo_cache/
-          --canonifyURLs[=false]: if true, all relative URLs will be canonicalized using baseURL
-          --config="": config file (default is path/config.yaml|json|toml)
-      -d, --destination="": filesystem path to write files to
-          --disableRSS[=false]: Do not build RSS files
-          --disableSitemap[=false]: Do not build Sitemap file
-          --editor="": edit new content with this editor, if provided
-          --ignoreCache[=false]: Ignores the cache directory for reading but still writes to it
-          --log[=false]: Enable Logging
-          --logFile="": Log File path (if set, logging enabled automatically)
-          --noTimes[=false]: Don't sync modification time of files
-          --pluralizeListTitles[=true]: Pluralize titles in lists using inflect
-          --preserveTaxonomyNames[=false]: Preserve taxonomy names as written ("Gérard Depardieu" vs "gerard-depardieu")
-      -s, --source="": filesystem path to read files relative from
-          --stepAnalysis[=false]: display memory and timing of different steps of the program
-      -t, --theme="": theme to use (located in /themes/THEMENAME/)
-          --uglyURLs[=false]: if true, use /filename.html instead of /filename/
-      -v, --verbose[=false]: verbose output
-          --verboseLog[=false]: verbose logging
-      -w, --watch[=false]: watch filesystem for changes and recreate as needed
+      -a, --author string    author name for copyright attribution (default "YOUR NAME")
+          --config string    config file (default is $HOME/.cobra.yaml)
+      -h, --help             help for cobra
+      -l, --license string   name of license for the project
+          --viper            use Viper for configuration (default true)

-    Use "hugo [command] --help" for more information about a command.
+    Use "cobra [command] --help" for more information about a command.


 Help is just a command like any other. There is no special logic or behavior
@ -557,38 +521,18 @@ around it. In fact, you can provide your own if you want.

 ### Defining your own help

-You can provide your own Help command or your own template for the default command to use.
-
-The default help command is
+You can provide your own Help command or your own template for the default command to use
+with followind functions:

 ```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.
-        Simply type ` + c.Name() + ` help [path to command] for full details.`,
-			Run: c.HelpFunc(),
-		}
-	}
-	c.AddCommand(c.helpCommand)
-}
-```
-
-You can provide your own command, function or template through the following methods:
-
-```go
-command.SetHelpCommand(cmd *Command)
-
-command.SetHelpFunc(f func(*Command, []string))
-
-command.SetHelpTemplate(s string)
+cmd.SetHelpCommand(cmd *Command)
+cmd.SetHelpFunc(f func(*Command, []string))
+cmd.SetHelpTemplate(s string)
 ```

 The latter two will also apply to any children commands.

-## Usage
+## Usage Message

 When the user provides an invalid flag or invalid command, Cobra responds by
 showing the user the 'usage'.
@ -597,73 +541,37 @@ showing the user the 'usage'.
 You may recognize this from the help above. That's because the default help
 embeds the usage as part of its output.

+    $ cobra --invalid
+    Error: unknown flag: --invalid
    Usage:
-      hugo [flags]
-      hugo [command]
+      cobra [command]

    Available Commands:
-      server          Hugo runs its own webserver to render the files
-      version         Print the version number of Hugo
-      config          Print the site configuration
-      check           Check content in the source directory
-      benchmark       Benchmark hugo by building a site a number of times.
-      convert         Convert your content to different formats
-      new             Create new content for your site
-      list            Listing out various types of content
-      undraft         Undraft changes the content's draft status from 'True' to 'False'
-      genautocomplete Generate shell autocompletion script for Hugo
-      gendoc          Generate Markdown documentation for the Hugo CLI.
-      genman          Generate man page for Hugo
-      import          Import your site from others.
+      add         Add a command to a Cobra Application
+      help        Help about any command
+      init        Initialize a Cobra Application

    Flags:
-      -b, --baseURL="": hostname (and path) to the root, e.g. http://spf13.com/
-      -D, --buildDrafts[=false]: include content marked as draft
-      -F, --buildFuture[=false]: include content with publishdate in the future
-          --cacheDir="": filesystem path to cache directory. Defaults: $TMPDIR/hugo_cache/
-          --canonifyURLs[=false]: if true, all relative URLs will be canonicalized using baseURL
-          --config="": config file (default is path/config.yaml|json|toml)
-      -d, --destination="": filesystem path to write files to
-          --disableRSS[=false]: Do not build RSS files
-          --disableSitemap[=false]: Do not build Sitemap file
-          --editor="": edit new content with this editor, if provided
-          --ignoreCache[=false]: Ignores the cache directory for reading but still writes to it
-          --log[=false]: Enable Logging
-          --logFile="": Log File path (if set, logging enabled automatically)
-          --noTimes[=false]: Don't sync modification time of files
-          --pluralizeListTitles[=true]: Pluralize titles in lists using inflect
-          --preserveTaxonomyNames[=false]: Preserve taxonomy names as written ("Gérard Depardieu" vs "gerard-depardieu")
-      -s, --source="": filesystem path to read files relative from
-          --stepAnalysis[=false]: display memory and timing of different steps of the program
-      -t, --theme="": theme to use (located in /themes/THEMENAME/)
-          --uglyURLs[=false]: if true, use /filename.html instead of /filename/
-      -v, --verbose[=false]: verbose output
-          --verboseLog[=false]: verbose logging
-      -w, --watch[=false]: watch filesystem for changes and recreate as needed
+      -a, --author string    author name for copyright attribution (default "YOUR NAME")
+          --config string    config file (default is $HOME/.cobra.yaml)
+      -h, --help             help for cobra
+      -l, --license string   name of license for the project
+          --viper            use Viper for configuration (default true)
+
+    Use "cobra [command] --help" for more information about a command.

 ### Defining your own usage
 You can provide your own usage function or template for Cobra to use.
-
-The default usage function is:
-
-```go
-return func(c *Command) error {
-	err := tmpl(c.Out(), c.UsageTemplate(), c)
-	return err
-}
-```
-
 Like help, the function and template are overridable through public methods:

 ```go
-command.SetUsageFunc(f func(*Command) error)
-
-command.SetUsageTemplate(s string)
+cmd.SetUsageFunc(f func(*Command) error)
+cmd.SetUsageTemplate(s string)
 ```

-## PreRun or PostRun Hooks
+## PreRun and PostRun Hooks

-It is possible to run functions before or after the main `Run` function of your command. The `PersistentPreRun` and `PreRun` functions will be executed before `Run`. `PersistentPostRun` and `PostRun` will be executed after `Run`.  The `Persistent*Run` functions will be inherrited by children if they do not declare their own.  These function are run in the following order:
+It is possible to run functions before or after the main `Run` function of your command. The `PersistentPreRun` and `PreRun` functions will be executed before `Run`. `PersistentPostRun` and `PostRun` will be executed after `Run`.  The `Persistent*Run` functions will be inherited by children if they do not declare their own.  These functions are run in the following order:

 - `PersistentPreRun`
 - `PreRun`
@ -724,58 +632,26 @@ func main() {
  rootCmd.AddCommand(subCmd)

  rootCmd.SetArgs([]string{""})
-	_ = rootCmd.Execute()
-	fmt.Print("\n")
+  rootCmd.Execute()
+  fmt.Println()
  rootCmd.SetArgs([]string{"sub", "arg1", "arg2"})
-	_ = rootCmd.Execute()
+  rootCmd.Execute()
 }
 ```

+Output:
+```
+Inside rootCmd PersistentPreRun with args: []
+Inside rootCmd PreRun with args: []
+Inside rootCmd Run with args: []
+Inside rootCmd PostRun with args: []
+Inside rootCmd PersistentPostRun with args: []

-## Alternative Error Handling
-
-Cobra also has functions where the return signature is an error. This allows for errors to bubble up to the top,
-providing a way to handle the errors in one location. The current list of functions that return an error is:
-
-* PersistentPreRunE
-* PreRunE
-* RunE
-* PostRunE
-* PersistentPostRunE
-
-If you would like to silence the default `error` and `usage` output in favor of your own, you can set `SilenceUsage`
-and `SilenceErrors` to `false` on the command. A child command respects these flags if they are set on the parent
-command.
-
-**Example Usage using RunE:**
-
-```go
-package main
-
-import (
-	"errors"
-	"log"
-
-	"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)
-	}
-}
+Inside rootCmd PersistentPreRun with args: [arg1 arg2]
+Inside subCmd PreRun with args: [arg1 arg2]
+Inside subCmd Run with args: [arg1 arg2]
+Inside subCmd PostRun with args: [arg1 arg2]
+Inside subCmd PersistentPostRun with args: [arg1 arg2]
 ```

 ## Suggestions when "unknown command" happens
@ -818,81 +694,28 @@ Did you mean this?
 Run 'kubectl help' for usage.
 ```

-## Generating Markdown-formatted documentation for your command
+## Generating documentation for your command

-Cobra can generate a Markdown-formatted document based on the subcommands, flags, etc. A simple example of how to do this for your command can be found in [Markdown Docs](doc/md_docs.md).
+Cobra can generate documentation based on subcommands, flags, etc. in the following formats:

-## Generating man pages for your command
+- [Markdown](doc/md_docs.md)
+- [ReStructured Text](doc/rest_docs.md)
+- [Man Page](doc/man_docs.md)

-Cobra can generate a man page based on the subcommands, flags, etc. A simple example of how to do this for your command can be found in [Man Docs](doc/man_docs.md).
-
-## Generating bash completions for your command
+## Generating bash completions

 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()
-```
-
-## Release Notes
-* **0.9.0** June 17, 2014
-  * flags can appears anywhere in the args (provided they are unambiguous)
-  * --help prints usage screen for app or command
-  * Prefix matching for commands
-  * Cleaner looking help and usage output
-  * Extensive test suite
-* **0.8.0** Nov 5, 2013
-  * Reworked interface to remove commander completely
-  * Command now primary structure
-  * No initialization needed
-  * Usage & Help templates & functions definable at any level
-  * Updated Readme
-* **0.7.0** Sept 24, 2013
-  * Needs more eyes
-  * Test suite
-  * Support for automatic error messages
-  * Support for help command
-  * Support for printing to any io.Writer instead of os.Stderr
-  * Support for persistent flags which cascade down tree
-  * Ready for integration into Hugo
-* **0.1.0** Sept 3, 2013
-  * Implement first draft
-
-## Extensions
-
-Libraries for extending Cobra:
-
-* [cmdns](https://github.com/gosuri/cmdns): Enables name spacing a command's immediate children. It provides an alternative way to structure subcommands, similar to `heroku apps:create` and `ovrclk clusters:launch`.
-
-## ToDo
-* Launch proper documentation site
-
-## Contributing
+# Contributing

 1. Fork it
-2. Create your feature branch (`git checkout -b my-new-feature`)
-3. Commit your changes (`git commit -am 'Add some feature'`)
-4. Push to the branch (`git push origin my-new-feature`)
-5. Create new Pull Request
+2. Download your fork to your PC (`git clone https://github.com/your_username/cobra && cd cobra`)
+3. Create your feature branch (`git checkout -b my-new-feature`)
+4. Make changes and add them (`git add .`)
+5. Commit your changes (`git commit -m 'Add some feature'`)
+6. Push to the branch (`git push origin my-new-feature`)
+7. Create new pull request

-## Contributors
-
-Names in no particular order:
-
-* [spf13](https://github.com/spf13),
-[eparis](https://github.com/eparis),
-[bep](https://github.com/bep), and many more!
-
-## License
+# License

 Cobra is released under the Apache 2.0 license. See [LICENSE.txt](https://github.com/spf13/cobra/blob/master/LICENSE.txt)
-
-
-[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/spf13/cobra/trend.png)](https://bitdeli.com/free "Bitdeli Badge")
--- a/vendor/github.com/spf13/cobra/args.go
+++ 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
+	}
+}
--- a/vendor/github.com/spf13/cobra/bash_completions.go
+++ b/vendor/github.com/spf13/cobra/bash_completions.go
@ -1,6 +1,7 @@
 package cobra

 import (
+	"bytes"
 	"fmt"
 	"io"
 	"os"
@ -10,19 +11,17 @@ import (
 	"github.com/spf13/pflag"
 )

+// Annotations for Bash completion.
 const (
-	BashCompFilenameExt     = "cobra_annotation_bash_completion_filename_extentions"
+	BashCompFilenameExt     = "cobra_annotation_bash_completion_filename_extensions"
 	BashCompCustom          = "cobra_annotation_bash_completion_custom"
 	BashCompOneRequiredFlag = "cobra_annotation_bash_completion_one_required_flag"
 	BashCompSubdirsInDir    = "cobra_annotation_bash_completion_subdirs_in_dir"
 )

-func preamble(out io.Writer, name string) error {
-	_, err := fmt.Fprintf(out, "# bash completion for %-36s -*- shell-script -*-\n", name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprint(out, `
+func writePreamble(buf *bytes.Buffer, name string) {
+	buf.WriteString(fmt.Sprintf("# bash completion for %-36s -*- shell-script -*-\n", name))
+	buf.WriteString(`
 __debug()
 {
    if [[ -n ${BASH_COMP_DEBUG_FILE} ]]; then
@ -87,13 +86,13 @@ __handle_reply()
                local index flag
                flag="${cur%%=*}"
                __index_of_word "${flag}" "${flags_with_completion[@]}"
-                if [[ ${index} -ge 0 ]]; then
                COMPREPLY=()
+                if [[ ${index} -ge 0 ]]; then
                    PREFIX=""
                    cur="${cur#*=}"
                    ${flags_completion[${index}]}
                    if [ -n "${ZSH_VERSION}" ]; then
-                        # zfs completion needs --flag= prefix
+                        # zsh completion needs --flag= prefix
                        eval "COMPREPLY=( \"\${COMPREPLY[@]/#/${flag}=}\" )"
                    fi
                fi
@ -133,7 +132,10 @@ __handle_reply()
        declare -F __custom_func >/dev/null && __custom_func
    fi

+    # available in bash-completion >= 2, not always present on macOS
+    if declare -F __ltrim_colon_completions >/dev/null; then
        __ltrim_colon_completions "$cur"
+    fi
 }

 # The arguments should be in the form "ext1|ext2|extn"
@ -224,7 +226,7 @@ __handle_command()
    fi
    c=$((c+1))
    __debug "${FUNCNAME[0]}: looking for ${next_command}"
-    declare -F $next_command >/dev/null && $next_command
+    declare -F "$next_command" >/dev/null && $next_command
 }

 __handle_word()
@ -247,16 +249,12 @@ __handle_word()
 }

 `)
-	return err
 }

-func postscript(w io.Writer, name string) error {
+func writePostscript(buf *bytes.Buffer, name string) {
 	name = strings.Replace(name, ":", "__", -1)
-	_, err := fmt.Fprintf(w, "__start_%s()\n", name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprintf(w, `{
+	buf.WriteString(fmt.Sprintf("__start_%s()\n", name))
+	buf.WriteString(fmt.Sprintf(`{
    local cur prev words cword
    declare -A flaghash 2>/dev/null || :
    if declare -F _init_completion >/dev/null 2>&1; then
@ -280,318 +278,227 @@ func postscript(w io.Writer, name string) error {
    __handle_word
 }

-`, name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprintf(w, `if [[ $(type -t compopt) = "builtin" ]]; then
+`, name))
+	buf.WriteString(fmt.Sprintf(`if [[ $(type -t compopt) = "builtin" ]]; then
    complete -o default -F __start_%s %s
 else
    complete -o default -o nospace -F __start_%s %s
 fi

-`, name, name, name, name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprintf(w, "# ex: ts=4 sw=4 et filetype=sh\n")
-	return err
+`, name, name, name, name))
+	buf.WriteString("# ex: ts=4 sw=4 et filetype=sh\n")
 }

-func writeCommands(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    commands=()\n"); err != nil {
-		return err
-	}
+func writeCommands(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    commands=()\n")
 	for _, c := range cmd.Commands() {
 		if !c.IsAvailableCommand() || c == cmd.helpCommand {
 			continue
 		}
-		if _, err := fmt.Fprintf(w, "    commands+=(%q)\n", c.Name()); err != nil {
-			return err
+		buf.WriteString(fmt.Sprintf("    commands+=(%q)\n", c.Name()))
 	}
-	}
-	_, err := fmt.Fprintf(w, "\n")
-	return err
+	buf.WriteString("\n")
 }

-func writeFlagHandler(name string, annotations map[string][]string, w io.Writer) error {
+func writeFlagHandler(buf *bytes.Buffer, name string, annotations map[string][]string) {
 	for key, value := range annotations {
 		switch key {
 		case BashCompFilenameExt:
-			_, err := fmt.Fprintf(w, "    flags_with_completion+=(%q)\n", name)
-			if err != nil {
-				return err
-			}
+			buf.WriteString(fmt.Sprintf("    flags_with_completion+=(%q)\n", name))

+			var ext string
 			if len(value) > 0 {
-				ext := "__handle_filename_extension_flag " + strings.Join(value, "|")
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
+				ext = "__handle_filename_extension_flag " + strings.Join(value, "|")
 			} else {
-				ext := "_filedir"
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
-			}
-			if err != nil {
-				return err
+				ext = "_filedir"
 			}
+			buf.WriteString(fmt.Sprintf("    flags_completion+=(%q)\n", ext))
 		case BashCompCustom:
-			_, err := fmt.Fprintf(w, "    flags_with_completion+=(%q)\n", name)
-			if err != nil {
-				return err
-			}
+			buf.WriteString(fmt.Sprintf("    flags_with_completion+=(%q)\n", name))
 			if len(value) > 0 {
 				handlers := strings.Join(value, "; ")
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", handlers)
+				buf.WriteString(fmt.Sprintf("    flags_completion+=(%q)\n", handlers))
 			} else {
-				_, err = fmt.Fprintf(w, "    flags_completion+=(:)\n")
-			}
-			if err != nil {
-				return err
+				buf.WriteString("    flags_completion+=(:)\n")
 			}
 		case BashCompSubdirsInDir:
-			_, err := fmt.Fprintf(w, "    flags_with_completion+=(%q)\n", name)
+			buf.WriteString(fmt.Sprintf("    flags_with_completion+=(%q)\n", name))

+			var ext string
 			if len(value) == 1 {
-				ext := "__handle_subdirs_in_dir_flag " + value[0]
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
+				ext = "__handle_subdirs_in_dir_flag " + value[0]
 			} else {
-				ext := "_filedir -d"
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
+				ext = "_filedir -d"
 			}
-			if err != nil {
-				return err
+			buf.WriteString(fmt.Sprintf("    flags_completion+=(%q)\n", ext))
 		}
 	}
 }
-	return nil
-}

-func writeShortFlag(flag *pflag.Flag, w io.Writer) error {
-	b := (len(flag.NoOptDefVal) > 0)
+func writeShortFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	name := flag.Shorthand
 	format := "    "
-	if !b {
+	if len(flag.NoOptDefVal) == 0 {
 		format += "two_word_"
 	}
 	format += "flags+=(\"-%s\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return writeFlagHandler("-"+name, flag.Annotations, w)
+	buf.WriteString(fmt.Sprintf(format, name))
+	writeFlagHandler(buf, "-"+name, flag.Annotations)
 }

-func writeFlag(flag *pflag.Flag, w io.Writer) error {
-	b := (len(flag.NoOptDefVal) > 0)
+func writeFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	name := flag.Name
 	format := "    flags+=(\"--%s"
-	if !b {
+	if len(flag.NoOptDefVal) == 0 {
 		format += "="
 	}
 	format += "\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return writeFlagHandler("--"+name, flag.Annotations, w)
+	buf.WriteString(fmt.Sprintf(format, name))
+	writeFlagHandler(buf, "--"+name, flag.Annotations)
 }

-func writeLocalNonPersistentFlag(flag *pflag.Flag, w io.Writer) error {
-	b := (len(flag.NoOptDefVal) > 0)
+func writeLocalNonPersistentFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	name := flag.Name
 	format := "    local_nonpersistent_flags+=(\"--%s"
-	if !b {
+	if len(flag.NoOptDefVal) == 0 {
 		format += "="
 	}
 	format += "\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return nil
+	buf.WriteString(fmt.Sprintf(format, name))
 }

-func writeFlags(cmd *Command, w io.Writer) error {
-	_, err := fmt.Fprintf(w, `    flags=()
+func writeFlags(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString(`    flags=()
    two_word_flags=()
    local_nonpersistent_flags=()
    flags_with_completion=()
    flags_completion=()

 `)
-	if err != nil {
-		return err
-	}
 	localNonPersistentFlags := cmd.LocalNonPersistentFlags()
-	var visitErr error
 	cmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
-		if err := writeFlag(flag, w); err != nil {
-			visitErr = err
+		if nonCompletableFlag(flag) {
 			return
 		}
+		writeFlag(buf, flag)
 		if len(flag.Shorthand) > 0 {
-			if err := writeShortFlag(flag, w); err != nil {
-				visitErr = err
-				return
-			}
+			writeShortFlag(buf, flag)
 		}
 		if localNonPersistentFlags.Lookup(flag.Name) != nil {
-			if err := writeLocalNonPersistentFlag(flag, w); err != nil {
-				visitErr = err
-				return
-			}
+			writeLocalNonPersistentFlag(buf, flag)
 		}
 	})
-	if visitErr != nil {
-		return visitErr
-	}
 	cmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
-		if err := writeFlag(flag, w); err != nil {
-			visitErr = err
+		if nonCompletableFlag(flag) {
 			return
 		}
+		writeFlag(buf, flag)
 		if len(flag.Shorthand) > 0 {
-			if err := writeShortFlag(flag, w); err != nil {
-				visitErr = err
-				return
-			}
+			writeShortFlag(buf, flag)
 		}
 	})
-	if visitErr != nil {
-		return visitErr
+
+	buf.WriteString("\n")
 }

-	_, err = fmt.Fprintf(w, "\n")
-	return err
-}
-
-func writeRequiredFlag(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    must_have_one_flag=()\n"); err != nil {
-		return err
-	}
+func writeRequiredFlag(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    must_have_one_flag=()\n")
 	flags := cmd.NonInheritedFlags()
-	var visitErr error
 	flags.VisitAll(func(flag *pflag.Flag) {
+		if nonCompletableFlag(flag) {
+			return
+		}
 		for key := range flag.Annotations {
 			switch key {
 			case BashCompOneRequiredFlag:
 				format := "    must_have_one_flag+=(\"--%s"
-				b := (flag.Value.Type() == "bool")
-				if !b {
+				if flag.Value.Type() != "bool" {
 					format += "="
 				}
 				format += "\")\n"
-				if _, err := fmt.Fprintf(w, format, flag.Name); err != nil {
-					visitErr = err
-					return
-				}
+				buf.WriteString(fmt.Sprintf(format, flag.Name))

 				if len(flag.Shorthand) > 0 {
-					if _, err := fmt.Fprintf(w, "    must_have_one_flag+=(\"-%s\")\n", flag.Shorthand); err != nil {
-						visitErr = err
-						return
-					}
+					buf.WriteString(fmt.Sprintf("    must_have_one_flag+=(\"-%s\")\n", flag.Shorthand))
 				}
 			}
 		}
 	})
-	return visitErr
 }

-func writeRequiredNouns(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    must_have_one_noun=()\n"); err != nil {
-		return err
-	}
+func writeRequiredNouns(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    must_have_one_noun=()\n")
 	sort.Sort(sort.StringSlice(cmd.ValidArgs))
 	for _, value := range cmd.ValidArgs {
-		if _, err := fmt.Fprintf(w, "    must_have_one_noun+=(%q)\n", value); err != nil {
-			return err
+		buf.WriteString(fmt.Sprintf("    must_have_one_noun+=(%q)\n", value))
 	}
 }
-	return nil
-}

-func writeArgAliases(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    noun_aliases=()\n"); err != nil {
-		return err
-	}
+func writeArgAliases(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    noun_aliases=()\n")
 	sort.Sort(sort.StringSlice(cmd.ArgAliases))
 	for _, value := range cmd.ArgAliases {
-		if _, err := fmt.Fprintf(w, "    noun_aliases+=(%q)\n", value); err != nil {
-			return err
+		buf.WriteString(fmt.Sprintf("    noun_aliases+=(%q)\n", value))
 	}
 }
-	return nil
-}

-func gen(cmd *Command, w io.Writer) error {
+func gen(buf *bytes.Buffer, cmd *Command) {
 	for _, c := range cmd.Commands() {
 		if !c.IsAvailableCommand() || c == cmd.helpCommand {
 			continue
 		}
-		if err := gen(c, w); err != nil {
-			return err
-		}
+		gen(buf, c)
 	}
 	commandName := cmd.CommandPath()
 	commandName = strings.Replace(commandName, " ", "_", -1)
 	commandName = strings.Replace(commandName, ":", "__", -1)
-	if _, err := fmt.Fprintf(w, "_%s()\n{\n", commandName); err != nil {
-		return err
-	}
-	if _, err := fmt.Fprintf(w, "    last_command=%q\n", commandName); err != nil {
-		return err
-	}
-	if err := writeCommands(cmd, w); err != nil {
-		return err
-	}
-	if err := writeFlags(cmd, w); err != nil {
-		return err
-	}
-	if err := writeRequiredFlag(cmd, w); err != nil {
-		return err
-	}
-	if err := writeRequiredNouns(cmd, w); err != nil {
-		return err
-	}
-	if err := writeArgAliases(cmd, w); err != nil {
-		return err
-	}
-	if _, err := fmt.Fprintf(w, "}\n\n"); err != nil {
-		return err
-	}
-	return nil
+	buf.WriteString(fmt.Sprintf("_%s()\n{\n", commandName))
+	buf.WriteString(fmt.Sprintf("    last_command=%q\n", commandName))
+	writeCommands(buf, cmd)
+	writeFlags(buf, cmd)
+	writeRequiredFlag(buf, cmd)
+	writeRequiredNouns(buf, cmd)
+	writeArgAliases(buf, cmd)
+	buf.WriteString("}\n\n")
 }

-func (cmd *Command) GenBashCompletion(w io.Writer) error {
-	if err := preamble(w, cmd.Name()); err != nil {
+// GenBashCompletion generates bash completion file and writes to the passed writer.
+func (c *Command) GenBashCompletion(w io.Writer) error {
+	buf := new(bytes.Buffer)
+	writePreamble(buf, c.Name())
+	if len(c.BashCompletionFunction) > 0 {
+		buf.WriteString(c.BashCompletionFunction + "\n")
+	}
+	gen(buf, c)
+	writePostscript(buf, c.Name())
+
+	_, err := buf.WriteTo(w)
 	return err
 }
-	if len(cmd.BashCompletionFunction) > 0 {
-		if _, err := fmt.Fprintf(w, "%s\n", cmd.BashCompletionFunction); err != nil {
-			return err
-		}
-	}
-	if err := gen(cmd, w); err != nil {
-		return err
-	}
-	return postscript(w, cmd.Name())
-}

-func (cmd *Command) GenBashCompletionFile(filename string) error {
+func nonCompletableFlag(flag *pflag.Flag) bool {
+	return flag.Hidden || len(flag.Deprecated) > 0
+}
+
+// GenBashCompletionFile generates bash completion file.
+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.
@ -601,20 +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.
--- a/vendor/github.com/spf13/cobra/cobra.go
+++ b/vendor/github.com/spf13/cobra/cobra.go
@ -29,6 +29,7 @@ import (
 var templateFuncs = template.FuncMap{
 	"trim":                    strings.TrimSpace,
 	"trimRightSpace":          trimRightSpace,
+	"trimTrailingWhitespaces": trimRightSpace,
 	"appendIfNotPresent":      appendIfNotPresent,
 	"rpad":                    rpad,
 	"gt":                      Gt,
@ -37,21 +38,31 @@ var templateFuncs = template.FuncMap{

 var initializers []func()

-// automatic prefix matching can be a dangerous thing to automatically enable in CLI tools.
-// Set this to true to enable it
+// EnablePrefixMatching allows to set automatic prefix matching. Automatic prefix matching can be a dangerous thing
+// to automatically enable in CLI tools.
+// Set this to true to enable it.
 var EnablePrefixMatching = false

 // EnableCommandSorting controls sorting of the slice of commands, which is turned on by default.
 // 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{}) {
 	templateFuncs[name] = tmplFunc
 }

-//AddTemplateFuncs adds multiple template functions availalble to Usage and
+// AddTemplateFuncs adds multiple template functions that are available to Usage and
 // Help template generation.
 func AddTemplateFuncs(tmplFuncs template.FuncMap) {
 	for k, v := range tmplFuncs {
@ -61,11 +72,11 @@ func AddTemplateFuncs(tmplFuncs template.FuncMap) {

 // OnInitialize takes a series of func() arguments and appends them to a slice of func().
 func OnInitialize(y ...func()) {
-	for _, x := range y {
-		initializers = append(initializers, x)
-	}
+	initializers = append(initializers, y...)
 }

+// FIXME Gt is unused by cobra and should be removed in a version 2. It exists only for compatibility with users of cobra.
+
 // Gt takes two types and checks whether the first type is greater than the second. In case of types Arrays, Chans,
 // Maps and Slices, Gt will compare their lengths. Ints are compared directly while strings are first parsed as
 // ints and then compared.
@ -96,6 +107,8 @@ func Gt(a interface{}, b interface{}) bool {
 	return left > right
 }

+// FIXME Eq is unused by cobra and should be removed in a version 2. It exists only for compatibility with users of cobra.
+
 // Eq takes two types and checks whether they are equal. Supported types are int and string. Unsupported types will panic.
 func Eq(a interface{}, b interface{}) bool {
 	av := reflect.ValueOf(a)
@ -116,7 +129,9 @@ func trimRightSpace(s string) string {
 	return strings.TrimRightFunc(s, unicode.IsSpace)
 }

-// appendIfNotPresent will append stringToAppend to the end of s, but only if it's not yet present in s
+// FIXME appendIfNotPresent is unused by cobra and should be removed in a version 2. It exists only for compatibility with users of cobra.
+
+// appendIfNotPresent will append stringToAppend to the end of s, but only if it's not yet present in s.
 func appendIfNotPresent(s, stringToAppend string) string {
 	if strings.Contains(s, stringToAppend) {
 		return s
@ -124,7 +139,7 @@ func appendIfNotPresent(s, stringToAppend string) string {
 	return s + " " + stringToAppend
 }

-//rpad adds padding to the right of a string
+// rpad adds padding to the right of a string.
 func rpad(s string, padding int) string {
 	template := fmt.Sprintf("%%-%ds", padding)
 	return fmt.Sprintf(template, s)
@ -138,7 +153,7 @@ func tmpl(w io.Writer, text string, data interface{}) error {
 	return t.Execute(w, data)
 }

-// ld compares two strings and returns the levenshtein distance between them
+// ld compares two strings and returns the levenshtein distance between them.
 func ld(s, t string, ignoreCase bool) int {
 	if ignoreCase {
 		s = strings.ToLower(s)
--- a/vendor/github.com/spf13/cobra/command.go
+++ b/vendor/github.com/spf13/cobra/command.go
--- 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)
--- a/vendor/github.com/spf13/cobra/zsh_completions.go
+++ b/vendor/github.com/spf13/cobra/zsh_completions.go
@ -0,0 +1,126 @@
+package cobra
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+// GenZshCompletionFile generates zsh completion file.
+func (c *Command) GenZshCompletionFile(filename string) error {
+	outFile, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	return c.GenZshCompletion(outFile)
+}
+
+// GenZshCompletion generates a zsh completion file and writes to the passed writer.
+func (c *Command) GenZshCompletion(w io.Writer) error {
+	buf := new(bytes.Buffer)
+
+	writeHeader(buf, c)
+	maxDepth := maxDepth(c)
+	writeLevelMapping(buf, maxDepth)
+	writeLevelCases(buf, maxDepth, c)
+
+	_, err := buf.WriteTo(w)
+	return err
+}
+
+func writeHeader(w io.Writer, cmd *Command) {
+	fmt.Fprintf(w, "#compdef %s\n\n", cmd.Name())
+}
+
+func maxDepth(c *Command) int {
+	if len(c.Commands()) == 0 {
+		return 0
+	}
+	maxDepthSub := 0
+	for _, s := range c.Commands() {
+		subDepth := maxDepth(s)
+		if subDepth > maxDepthSub {
+			maxDepthSub = subDepth
+		}
+	}
+	return 1 + maxDepthSub
+}
+
+func writeLevelMapping(w io.Writer, numLevels int) {
+	fmt.Fprintln(w, `_arguments \`)
+	for i := 1; i <= numLevels; i++ {
+		fmt.Fprintf(w, `  '%d: :->level%d' \`, i, i)
+		fmt.Fprintln(w)
+	}
+	fmt.Fprintf(w, `  '%d: :%s'`, numLevels+1, "_files")
+	fmt.Fprintln(w)
+}
+
+func writeLevelCases(w io.Writer, maxDepth int, root *Command) {
+	fmt.Fprintln(w, "case $state in")
+	defer fmt.Fprintln(w, "esac")
+
+	for i := 1; i <= maxDepth; i++ {
+		fmt.Fprintf(w, "  level%d)\n", i)
+		writeLevel(w, root, i)
+		fmt.Fprintln(w, "  ;;")
+	}
+	fmt.Fprintln(w, "  *)")
+	fmt.Fprintln(w, "    _arguments '*: :_files'")
+	fmt.Fprintln(w, "  ;;")
+}
+
+func writeLevel(w io.Writer, root *Command, i int) {
+	fmt.Fprintf(w, "    case $words[%d] in\n", i)
+	defer fmt.Fprintln(w, "    esac")
+
+	commands := filterByLevel(root, i)
+	byParent := groupByParent(commands)
+
+	for p, c := range byParent {
+		names := names(c)
+		fmt.Fprintf(w, "      %s)\n", p)
+		fmt.Fprintf(w, "        _arguments '%d: :(%s)'\n", i, strings.Join(names, " "))
+		fmt.Fprintln(w, "      ;;")
+	}
+	fmt.Fprintln(w, "      *)")
+	fmt.Fprintln(w, "        _arguments '*: :_files'")
+	fmt.Fprintln(w, "      ;;")
+
+}
+
+func filterByLevel(c *Command, l int) []*Command {
+	cs := make([]*Command, 0)
+	if l == 0 {
+		cs = append(cs, c)
+		return cs
+	}
+	for _, s := range c.Commands() {
+		cs = append(cs, filterByLevel(s, l-1)...)
+	}
+	return cs
+}
+
+func groupByParent(commands []*Command) map[string][]*Command {
+	m := make(map[string][]*Command)
+	for _, c := range commands {
+		parent := c.Parent()
+		if parent == nil {
+			continue
+		}
+		m[parent.Name()] = append(m[parent.Name()], c)
+	}
+	return m
+}
+
+func names(commands []*Command) []string {
+	ns := make([]string, len(commands))
+	for i, c := range commands {
+		ns[i] = c.Name()
+	}
+	return ns
+}
--- a/vendor/github.com/spf13/pflag/README.md
+++ b/vendor/github.com/spf13/pflag/README.md
@ -246,6 +246,25 @@ It is possible to mark a flag as hidden, meaning it will still function as norma
 flags.MarkHidden("secretFlag")
 ```

+## Disable sorting of flags
+`pflag` allows you to disable sorting of flags for help and usage message.
+
+**Example**:
+```go
+flags.BoolP("verbose", "v", false, "verbose output")
+flags.String("coolflag", "yeaah", "it's really cool flag")
+flags.Int("usefulflag", 777, "sometimes it's very useful")
+flags.SortFlags = false
+flags.PrintDefaults()
+```
+**Output**:
+```
+  -v, --verbose           verbose output
+      --coolflag string   it's really cool flag (default "yeaah")
+      --usefulflag int    sometimes it's very useful (default 777)
+```
+
+
 ## Supporting Go flags when using pflag
 In order to support flags defined using Go's `flag` package, they must be added to the `pflag` flagset. This is usually necessary
 to support flags defined by third-party dependencies (e.g. `golang/glog`).
@ -270,8 +289,8 @@ func main() {
 You can see the full reference documentation of the pflag package
 [at godoc.org][3], or through go's standard documentation system by
 running `godoc -http=:6060` and browsing to
-[http://localhost:6060/pkg/github.com/ogier/pflag][2] after
+[http://localhost:6060/pkg/github.com/spf13/pflag][2] after
 installation.

-[2]: http://localhost:6060/pkg/github.com/ogier/pflag
-[3]: http://godoc.org/github.com/ogier/pflag
+[2]: http://localhost:6060/pkg/github.com/spf13/pflag
+[3]: http://godoc.org/github.com/spf13/pflag
--- a/vendor/github.com/spf13/pflag/count.go
+++ b/vendor/github.com/spf13/pflag/count.go
@ -83,7 +83,9 @@ func (f *FlagSet) CountP(name, shorthand string, usage string) *int {
 	return p
 }

-// Count like Count only the flag is placed on the CommandLine isntead of a given flag set
+// Count defines a count flag with specified name, default value, and usage string.
+// The return value is the address of an int variable that stores the value of the flag.
+// A count flag will add 1 to its value evey time it is found on the command line
 func Count(name string, usage string) *int {
 	return CommandLine.CountP(name, "", usage)
 }
--- a/vendor/github.com/spf13/pflag/flag.go
+++ b/vendor/github.com/spf13/pflag/flag.go
@ -16,7 +16,7 @@ pflag is a drop-in replacement of Go's native flag package. If you import
 pflag under the name "flag" then all code should continue to function
 with no changes.

-	import flag "github.com/ogier/pflag"
+	import flag "github.com/spf13/pflag"

 There is one exception to this: if you directly instantiate the Flag struct
 there is one more field "Shorthand" that you will need to set.
@ -134,14 +134,21 @@ type FlagSet struct {
 	// a custom error handler.
 	Usage func()

+	// SortFlags is used to indicate, if user wants to have sorted flags in
+	// help/usage messages.
+	SortFlags bool
+
 	name              string
 	parsed            bool
 	actual            map[NormalizedName]*Flag
+	orderedActual     []*Flag
+	sortedActual      []*Flag
 	formal            map[NormalizedName]*Flag
+	orderedFormal     []*Flag
+	sortedFormal      []*Flag
 	shorthands        map[byte]*Flag
 	args              []string // arguments after flags
 	argsLenAtDash     int      // len(args) when a '--' was located when parsing, or -1 if no --
-	exitOnError       bool     // does the program exit if there's an error?
 	errorHandling     ErrorHandling
 	output            io.Writer // nil means stderr; use out() accessor
 	interspersed      bool      // allow interspersed option/non-option args
@ -194,11 +201,13 @@ func sortFlags(flags map[NormalizedName]*Flag) []*Flag {
 // "--getUrl" which may also be translated to "geturl" and everything will work.
 func (f *FlagSet) SetNormalizeFunc(n func(f *FlagSet, name string) NormalizedName) {
 	f.normalizeNameFunc = n
-	for k, v := range f.formal {
-		delete(f.formal, k)
-		nname := f.normalizeFlagName(string(k))
-		f.formal[nname] = v
+	f.sortedFormal = f.sortedFormal[:0]
+	for k, v := range f.orderedFormal {
+		delete(f.formal, NormalizedName(v.Name))
+		nname := f.normalizeFlagName(v.Name)
 		v.Name = string(nname)
+		f.formal[nname] = v
+		f.orderedFormal[k] = v
 	}
 }

@ -229,10 +238,25 @@ func (f *FlagSet) SetOutput(output io.Writer) {
 	f.output = output
 }

-// VisitAll visits the flags in lexicographical order, calling fn for each.
+// VisitAll visits the flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
 // It visits all flags, even those not set.
 func (f *FlagSet) VisitAll(fn func(*Flag)) {
-	for _, flag := range sortFlags(f.formal) {
+	if len(f.formal) == 0 {
+		return
+	}
+
+	var flags []*Flag
+	if f.SortFlags {
+		if len(f.formal) != len(f.sortedFormal) {
+			f.sortedFormal = sortFlags(f.formal)
+		}
+		flags = f.sortedFormal
+	} else {
+		flags = f.orderedFormal
+	}
+
+	for _, flag := range flags {
 		fn(flag)
 	}
 }
@ -253,22 +277,39 @@ func (f *FlagSet) HasAvailableFlags() bool {
 	return false
 }

-// VisitAll visits the command-line flags in lexicographical order, calling
-// fn for each.  It visits all flags, even those not set.
+// VisitAll visits the command-line flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
+// It visits all flags, even those not set.
 func VisitAll(fn func(*Flag)) {
 	CommandLine.VisitAll(fn)
 }

-// Visit visits the flags in lexicographical order, calling fn for each.
+// Visit visits the flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
 // It visits only those flags that have been set.
 func (f *FlagSet) Visit(fn func(*Flag)) {
-	for _, flag := range sortFlags(f.actual) {
+	if len(f.actual) == 0 {
+		return
+	}
+
+	var flags []*Flag
+	if f.SortFlags {
+		if len(f.actual) != len(f.sortedActual) {
+			f.sortedActual = sortFlags(f.actual)
+		}
+		flags = f.sortedActual
+	} else {
+		flags = f.orderedActual
+	}
+
+	for _, flag := range flags {
 		fn(flag)
 	}
 }

-// Visit visits the command-line flags in lexicographical order, calling fn
-// for each.  It visits only those flags that have been set.
+// Visit visits the command-line flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
+// It visits only those flags that have been set.
 func Visit(fn func(*Flag)) {
 	CommandLine.Visit(fn)
 }
@ -278,6 +319,22 @@ func (f *FlagSet) Lookup(name string) *Flag {
 	return f.lookup(f.normalizeFlagName(name))
 }

+// ShorthandLookup returns the Flag structure of the short handed flag,
+// returning nil if none exists.
+// It panics, if len(name) > 1.
+func (f *FlagSet) ShorthandLookup(name string) *Flag {
+	if name == "" {
+		return nil
+	}
+	if len(name) > 1 {
+		msg := fmt.Sprintf("can not look up shorthand which is more than one ASCII character: %q", name)
+		fmt.Fprintf(f.out(), msg)
+		panic(msg)
+	}
+	c := name[0]
+	return f.shorthands[c]
+}
+
 // lookup returns the Flag structure of the named flag, returning nil if none exists.
 func (f *FlagSet) lookup(name NormalizedName) *Flag {
 	return f.formal[name]
@ -319,7 +376,7 @@ func (f *FlagSet) MarkDeprecated(name string, usageMessage string) error {
 	if flag == nil {
 		return fmt.Errorf("flag %q does not exist", name)
 	}
-	if len(usageMessage) == 0 {
+	if usageMessage == "" {
 		return fmt.Errorf("deprecated message for flag %q must be set", name)
 	}
 	flag.Deprecated = usageMessage
@ -334,7 +391,7 @@ func (f *FlagSet) MarkShorthandDeprecated(name string, usageMessage string) erro
 	if flag == nil {
 		return fmt.Errorf("flag %q does not exist", name)
 	}
-	if len(usageMessage) == 0 {
+	if usageMessage == "" {
 		return fmt.Errorf("deprecated message for flag %q must be set", name)
 	}
 	flag.ShorthandDeprecated = usageMessage
@ -358,6 +415,12 @@ func Lookup(name string) *Flag {
 	return CommandLine.Lookup(name)
 }

+// ShorthandLookup returns the Flag structure of the short handed flag,
+// returning nil if none exists.
+func ShorthandLookup(name string) *Flag {
+	return CommandLine.ShorthandLookup(name)
+}
+
 // Set sets the value of the named flag.
 func (f *FlagSet) Set(name, value string) error {
 	normalName := f.normalizeFlagName(name)
@ -365,17 +428,28 @@ func (f *FlagSet) Set(name, value string) error {
 	if !ok {
 		return fmt.Errorf("no such flag -%v", name)
 	}
+
 	err := flag.Value.Set(value)
 	if err != nil {
-		return err
+		var flagName string
+		if flag.Shorthand != "" && flag.ShorthandDeprecated == "" {
+			flagName = fmt.Sprintf("-%s, --%s", flag.Shorthand, flag.Name)
+		} else {
+			flagName = fmt.Sprintf("--%s", flag.Name)
 		}
+		return fmt.Errorf("invalid argument %q for %q flag: %v", value, flagName, err)
+	}
+
 	if f.actual == nil {
 		f.actual = make(map[NormalizedName]*Flag)
 	}
 	f.actual[normalName] = flag
+	f.orderedActual = append(f.orderedActual, flag)
+
 	flag.Changed = true
-	if len(flag.Deprecated) > 0 {
-		fmt.Fprintf(os.Stderr, "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
+
+	if flag.Deprecated != "" {
+		fmt.Fprintf(f.out(), "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
 	}
 	return nil
 }
@ -557,28 +631,28 @@ func wrap(i, w int, s string) string {
 // for all flags in the FlagSet. Wrapped to `cols` columns (0 for no
 // wrapping)
 func (f *FlagSet) FlagUsagesWrapped(cols int) string {
-	x := new(bytes.Buffer)
+	buf := new(bytes.Buffer)

 	lines := make([]string, 0, len(f.formal))

 	maxlen := 0
 	f.VisitAll(func(flag *Flag) {
-		if len(flag.Deprecated) > 0 || flag.Hidden {
+		if flag.Deprecated != "" || flag.Hidden {
 			return
 		}

 		line := ""
-		if len(flag.Shorthand) > 0 && len(flag.ShorthandDeprecated) == 0 {
+		if flag.Shorthand != "" && flag.ShorthandDeprecated == "" {
 			line = fmt.Sprintf("  -%s, --%s", flag.Shorthand, flag.Name)
 		} else {
 			line = fmt.Sprintf("      --%s", flag.Name)
 		}

 		varname, usage := UnquoteUsage(flag)
-		if len(varname) > 0 {
+		if varname != "" {
 			line += " " + varname
 		}
-		if len(flag.NoOptDefVal) > 0 {
+		if flag.NoOptDefVal != "" {
 			switch flag.Value.Type() {
 			case "string":
 				line += fmt.Sprintf("[=\"%s\"]", flag.NoOptDefVal)
@ -601,7 +675,7 @@ func (f *FlagSet) FlagUsagesWrapped(cols int) string {
 		line += usage
 		if !flag.defaultIsZeroValue() {
 			if flag.Value.Type() == "string" {
-				line += fmt.Sprintf(" (default \"%s\")", flag.DefValue)
+				line += fmt.Sprintf(" (default %q)", flag.DefValue)
 			} else {
 				line += fmt.Sprintf(" (default %s)", flag.DefValue)
 			}
@ -614,10 +688,10 @@ func (f *FlagSet) FlagUsagesWrapped(cols int) string {
 		sidx := strings.Index(line, "\x00")
 		spacing := strings.Repeat(" ", maxlen-sidx)
 		// maxlen + 2 comes from + 1 for the \x00 and + 1 for the (deliberate) off-by-one in maxlen-sidx
-		fmt.Fprintln(x, line[:sidx], spacing, wrap(maxlen+2, cols, line[sidx+1:]))
+		fmt.Fprintln(buf, line[:sidx], spacing, wrap(maxlen+2, cols, line[sidx+1:]))
 	}

-	return x.String()
+	return buf.String()
 }

 // FlagUsages returns a string containing the usage information for all flags in
@ -714,11 +788,10 @@ func (f *FlagSet) VarP(value Value, name, shorthand, usage string) {

 // AddFlag will add the flag to the FlagSet
 func (f *FlagSet) AddFlag(flag *Flag) {
-	// Call normalizeFlagName function only once
 	normalizedFlagName := f.normalizeFlagName(flag.Name)

-	_, alreadythere := f.formal[normalizedFlagName]
-	if alreadythere {
+	_, alreadyThere := f.formal[normalizedFlagName]
+	if alreadyThere {
 		msg := fmt.Sprintf("%s flag redefined: %s", f.name, flag.Name)
 		fmt.Fprintln(f.out(), msg)
 		panic(msg) // Happens only if flags are declared with identical names
@ -729,28 +802,31 @@ func (f *FlagSet) AddFlag(flag *Flag) {

 	flag.Name = string(normalizedFlagName)
 	f.formal[normalizedFlagName] = flag
+	f.orderedFormal = append(f.orderedFormal, flag)

-	if len(flag.Shorthand) == 0 {
+	if flag.Shorthand == "" {
 		return
 	}
 	if len(flag.Shorthand) > 1 {
-		fmt.Fprintf(f.out(), "%s shorthand more than ASCII character: %s\n", f.name, flag.Shorthand)
-		panic("shorthand is more than one character")
+		msg := fmt.Sprintf("%q shorthand is more than one ASCII character", flag.Shorthand)
+		fmt.Fprintf(f.out(), msg)
+		panic(msg)
 	}
 	if f.shorthands == nil {
 		f.shorthands = make(map[byte]*Flag)
 	}
 	c := flag.Shorthand[0]
-	old, alreadythere := f.shorthands[c]
-	if alreadythere {
-		fmt.Fprintf(f.out(), "%s shorthand reused: %q for %s already used for %s\n", f.name, c, flag.Name, old.Name)
-		panic("shorthand redefinition")
+	used, alreadyThere := f.shorthands[c]
+	if alreadyThere {
+		msg := fmt.Sprintf("unable to redefine %q shorthand in %q flagset: it's already used for %q flag", c, f.name, used.Name)
+		fmt.Fprintf(f.out(), msg)
+		panic(msg)
 	}
 	f.shorthands[c] = flag
 }

 // AddFlagSet adds one FlagSet to another. If a flag is already present in f
-// the flag from newSet will be ignored
+// the flag from newSet will be ignored.
 func (f *FlagSet) AddFlagSet(newSet *FlagSet) {
 	if newSet == nil {
 		return
@ -798,34 +874,6 @@ func (f *FlagSet) usage() {
 	}
 }

-func (f *FlagSet) setFlag(flag *Flag, value string, origArg string) error {
-	if err := flag.Value.Set(value); err != nil {
-		return f.failf("invalid argument %q for %s: %v", value, origArg, err)
-	}
-	// mark as visited for Visit()
-	if f.actual == nil {
-		f.actual = make(map[NormalizedName]*Flag)
-	}
-	f.actual[f.normalizeFlagName(flag.Name)] = flag
-	flag.Changed = true
-	if len(flag.Deprecated) > 0 {
-		fmt.Fprintf(os.Stderr, "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
-	}
-	if len(flag.ShorthandDeprecated) > 0 && containsShorthand(origArg, flag.Shorthand) {
-		fmt.Fprintf(os.Stderr, "Flag shorthand -%s has been deprecated, %s\n", flag.Shorthand, flag.ShorthandDeprecated)
-	}
-	return nil
-}
-
-func containsShorthand(arg, shorthand string) bool {
-	// filter out flags --<flag_name>
-	if strings.HasPrefix(arg, "-") {
-		return false
-	}
-	arg = strings.SplitN(arg, "=", 2)[0]
-	return strings.Contains(arg, shorthand)
-}
-
 func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []string, err error) {
 	a = args
 	name := s[2:]
@ -833,10 +881,11 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
 		err = f.failf("bad flag syntax: %s", s)
 		return
 	}
+
 	split := strings.SplitN(name, "=", 2)
 	name = split[0]
-	flag, alreadythere := f.formal[f.normalizeFlagName(name)]
-	if !alreadythere {
+	flag, exists := f.formal[f.normalizeFlagName(name)]
+	if !exists {
 		if name == "help" { // special case for nice help message.
 			f.usage()
 			return a, ErrHelp
@ -844,11 +893,12 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
 		err = f.failf("unknown flag: --%s", name)
 		return
 	}
+
 	var value string
 	if len(split) == 2 {
 		// '--flag=arg'
 		value = split[1]
-	} else if len(flag.NoOptDefVal) > 0 {
+	} else if flag.NoOptDefVal != "" {
 		// '--flag' (arg was optional)
 		value = flag.NoOptDefVal
 	} else if len(a) > 0 {
@ -860,7 +910,8 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
 		err = f.failf("flag needs an argument: %s", s)
 		return
 	}
-	err = fn(flag, value, s)
+
+	err = fn(flag, value)
 	return
 }

@ -868,38 +919,49 @@ func (f *FlagSet) parseSingleShortArg(shorthands string, args []string, fn parse
 	if strings.HasPrefix(shorthands, "test.") {
 		return
 	}
+
 	outArgs = args
 	outShorts = shorthands[1:]
 	c := shorthands[0]

-	flag, alreadythere := f.shorthands[c]
-	if !alreadythere {
+	flag, exists := f.shorthands[c]
+	if !exists {
 		if c == 'h' { // special case for nice help message.
 			f.usage()
 			err = ErrHelp
 			return
 		}
-		//TODO continue on error
 		err = f.failf("unknown shorthand flag: %q in -%s", c, shorthands)
 		return
 	}
+
 	var value string
 	if len(shorthands) > 2 && shorthands[1] == '=' {
+		// '-f=arg'
 		value = shorthands[2:]
 		outShorts = ""
-	} else if len(flag.NoOptDefVal) > 0 {
+	} else if flag.NoOptDefVal != "" {
+		// '-f' (arg was optional)
 		value = flag.NoOptDefVal
 	} else if len(shorthands) > 1 {
+		// '-farg'
 		value = shorthands[1:]
 		outShorts = ""
 	} else if len(args) > 0 {
+		// '-f arg'
 		value = args[0]
 		outArgs = args[1:]
 	} else {
+		// '-f' (arg was required)
 		err = f.failf("flag needs an argument: %q in -%s", c, shorthands)
 		return
 	}
-	err = fn(flag, value, shorthands)
+
+	if flag.ShorthandDeprecated != "" {
+		fmt.Fprintf(f.out(), "Flag shorthand -%s has been deprecated, %s\n", flag.Shorthand, flag.ShorthandDeprecated)
+	}
+
+	err = fn(flag, value)
 	return
 }

@ -907,6 +969,7 @@ func (f *FlagSet) parseShortArg(s string, args []string, fn parseFunc) (a []stri
 	a = args
 	shorthands := s[1:]

+	// "shorthands" can be a series of shorthand letters of flags (e.g. "-vvv").
 	for len(shorthands) > 0 {
 		shorthands, a, err = f.parseSingleShortArg(shorthands, args, fn)
 		if err != nil {
@ -954,13 +1017,18 @@ func (f *FlagSet) parseArgs(args []string, fn parseFunc) (err error) {
 // The return value will be ErrHelp if -help was set but not defined.
 func (f *FlagSet) Parse(arguments []string) error {
 	f.parsed = true
-	f.args = make([]string, 0, len(arguments))

-	assign := func(flag *Flag, value, origArg string) error {
-		return f.setFlag(flag, value, origArg)
+	if len(arguments) < 0 {
+		return nil
 	}

-	err := f.parseArgs(arguments, assign)
+	f.args = make([]string, 0, len(arguments))
+
+	set := func(flag *Flag, value string) error {
+		return f.Set(flag.Name, value)
+	}
+
+	err := f.parseArgs(arguments, set)
 	if err != nil {
 		switch f.errorHandling {
 		case ContinueOnError:
@ -974,7 +1042,7 @@ func (f *FlagSet) Parse(arguments []string) error {
 	return nil
 }

-type parseFunc func(flag *Flag, value, origArg string) error
+type parseFunc func(flag *Flag, value string) error

 // ParseAll parses flag definitions from the argument list, which should not
 // include the command name. The arguments for fn are flag and value. Must be
@ -985,11 +1053,7 @@ func (f *FlagSet) ParseAll(arguments []string, fn func(flag *Flag, value string)
 	f.parsed = true
 	f.args = make([]string, 0, len(arguments))

-	assign := func(flag *Flag, value, origArg string) error {
-		return fn(flag, value)
-	}
-
-	err := f.parseArgs(arguments, assign)
+	err := f.parseArgs(arguments, fn)
 	if err != nil {
 		switch f.errorHandling {
 		case ContinueOnError:
@ -1036,14 +1100,15 @@ func Parsed() bool {
 // CommandLine is the default set of command-line flags, parsed from os.Args.
 var CommandLine = NewFlagSet(os.Args[0], ExitOnError)

-// NewFlagSet returns a new, empty flag set with the specified name and
-// error handling property.
+// NewFlagSet returns a new, empty flag set with the specified name,
+// error handling property and SortFlags set to true.
 func NewFlagSet(name string, errorHandling ErrorHandling) *FlagSet {
 	f := &FlagSet{
 		name:          name,
 		errorHandling: errorHandling,
 		argsLenAtDash: -1,
 		interspersed:  true,
+		SortFlags:     true,
 	}
 	return f
 }