Repository: spf13/cobra
Pull request #306 (2016-07-16 15:12:44)

Add "docker" to readme
Docker (https://github.com/docker/docker) now also uses Cobra for the CLI. A majority of the
commands have been migrated (still some left), but adding it already :)



Patch:
diff --git a/.travis.yml b/.travis.yml
index 2bbf623..42d1f57 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,14 @@
 language: go
-go:
-  - 1.4.3
-  - 1.5.4
-  - 1.6.2
-  - tip
 
 matrix:
+  include:
+    - go: 1.4.3
+      env: NOVET=true # No bundled vet.
+    - go: 1.5.4
+    - go: 1.6.4
+    - go: 1.7.5
+    - go: 1.8
+    - go: tip
   allow_failures:
     - go: tip
 
@@ -16,3 +19,7 @@ before_install:
 script:
   - PATH=$PATH:$PWD/bin go test -v ./...
   - go build
+  - diff -u <(echo -n) <(gofmt -d -s .)
+  - if [ -z $NOVET ]; then
+      diff -u <(echo -n) <(go tool vet . 2>&1 | grep -vE 'ExampleCommand|bash_completions.*Fprint');
+    fi
diff --git a/README.md b/README.md
index 34c79eb..2de9840 100644
--- a/README.md
+++ b/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)
+* [Docker](https://github.com/docker/docker)
 * [Docker (distribution)](https://github.com/docker/distribution)
 * [OpenShift](https://www.openshift.com/)
 * [Delve](https://github.com/derekparker/delve)
@@ -157,7 +158,12 @@ 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 {
@@ -172,6 +178,12 @@ 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:
+
+    > go install github.com/spf13/cobra/cobra
+
+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
@@ -307,7 +319,12 @@ 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 {
@@ -331,6 +348,7 @@ package cmd
 
 import (
 	"github.com/spf13/cobra"
+	"fmt"
 )
 
 func init() {
@@ -657,7 +675,7 @@ command.SetUsageTemplate(s string)
 
 ## PreRun or 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`
@@ -738,7 +756,7 @@ providing a way to handle the errors in one location. The current list of functi
 * 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
+and `SilenceErrors` to `true` on the command. A child command respects these flags if they are set on the parent
 command.
 
 **Example Usage using RunE:**
diff --git a/bash_completions.go b/bash_completions.go
index 236dee6..8820ba8 100644
--- a/bash_completions.go
+++ b/bash_completions.go
@@ -10,8 +10,9 @@ 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"
@@ -22,7 +23,7 @@ func preamble(out io.Writer, name string) error {
 	if err != nil {
 		return err
 	}
-	_, err = fmt.Fprint(out, `
+	preamStr := `
 __debug()
 {
     if [[ -n ${BASH_COMP_DEBUG_FILE} ]]; then
@@ -246,7 +247,8 @@ __handle_word()
     __handle_word
 }
 
-`)
+`
+	_, err = fmt.Fprint(out, preamStr)
 	return err
 }
 
@@ -401,10 +403,8 @@ func writeLocalNonPersistentFlag(flag *pflag.Flag, w io.Writer) error {
 		format += "="
 	}
 	format += "\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return nil
+	_, err := fmt.Fprintf(w, format, name)
+	return err
 }
 
 func writeFlags(cmd *Command, w io.Writer) error {
@@ -421,6 +421,9 @@ func writeFlags(cmd *Command, w io.Writer) error {
 	localNonPersistentFlags := cmd.LocalNonPersistentFlags()
 	var visitErr error
 	cmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
+		if nonCompletableFlag(flag) {
+			return
+		}
 		if err := writeFlag(flag, w); err != nil {
 			visitErr = err
 			return
@@ -442,6 +445,9 @@ func writeFlags(cmd *Command, w io.Writer) error {
 		return visitErr
 	}
 	cmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
+		if nonCompletableFlag(flag) {
+			return
+		}
 		if err := writeFlag(flag, w); err != nil {
 			visitErr = err
 			return
@@ -468,6 +474,9 @@ func writeRequiredFlag(cmd *Command, w io.Writer) error {
 	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:
@@ -559,6 +568,7 @@ func gen(cmd *Command, w io.Writer) error {
 	return nil
 }
 
+// GenBashCompletion generates bash completion file and writes to the passed writer.
 func (cmd *Command) GenBashCompletion(w io.Writer) error {
 	if err := preamble(w, cmd.Name()); err != nil {
 		return err
@@ -574,6 +584,11 @@ func (cmd *Command) GenBashCompletion(w io.Writer) error {
 	return postscript(w, cmd.Name())
 }
 
+func nonCompletableFlag(flag *pflag.Flag) bool {
+	return flag.Hidden || len(flag.Deprecated) > 0
+}
+
+// GenBashCompletionFile generates bash completion file.
 func (cmd *Command) GenBashCompletionFile(filename string) error {
 	outFile, err := os.Create(filename)
 	if err != nil {
diff --git a/bash_completions.md b/bash_completions.md
index 6e3b71f..7fa970f 100644
--- a/bash_completions.md
+++ b/bash_completions.md
@@ -18,7 +18,7 @@ func main() {
 }
 ```
 
-That will get you completions of subcommands and flags. If you make additional annotations to your code, you can get even more intelligent and flexible behavior.
+`out.sh` will get you completions of subcommands and flags. Copy it to `/etc/bash_completion.d/` as described [here](https://debian-administration.org/article/316/An_introduction_to_bash_completion_part_1) and reset your terminal to use autocompletion. If you make additional annotations to your code, you can get even more intelligent and flexible behavior.
 
 ## Creating your own custom functions
 
diff --git a/cobra.go b/cobra.go
index 93a2c0f..9605b98 100644
--- a/cobra.go
+++ b/cobra.go
@@ -37,38 +37,37 @@ 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.
+// EnableCommandSorting controls sorting of the slice of commands, which is turned on by default.
+// To disable sorting, set it to false.
 var EnableCommandSorting = true
 
-//AddTemplateFunc adds a template function that's available to Usage and Help
-//template generation.
+// 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
-//Help template generation.
+// AddTemplateFuncs adds multiple template functions availalble to Usage and
+// Help template generation.
 func AddTemplateFuncs(tmplFuncs template.FuncMap) {
 	for k, v := range tmplFuncs {
 		templateFuncs[k] = v
 	}
 }
 
-//OnInitialize takes a series of func() arguments and appends them to a slice of func().
+// 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...)
 }
 
-//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.
+// 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.
 func Gt(a interface{}, b interface{}) bool {
 	var left, right int64
 	av := reflect.ValueOf(a)
@@ -96,7 +95,7 @@ func Gt(a interface{}, b interface{}) bool {
 	return left > right
 }
 
-//Eq takes two types and checks whether they are equal. Supported types are int and string. Unsupported types will panic.
+// 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)
 	bv := reflect.ValueOf(b)
@@ -116,7 +115,7 @@ 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
+// 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 +123,7 @@ 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 +137,7 @@ 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)
diff --git a/command.go b/command.go
index 5b64187..ae3930d 100644
--- a/command.go
+++ b/command.go
@@ -57,6 +57,9 @@ type Command struct {
 	Deprecated string
 	// Is this command hidden and should NOT show up in the list of available commands?
 	Hidden bool
+	// Annotations are key/value pairs that can be used by applications to identify or
+	// group commands
+	Annotations map[string]string
 	// Full set of flags
 	flags *flag.FlagSet
 	// Set of flags childrens of this command will inherit
@@ -109,10 +112,11 @@ type Command struct {
 
 	flagErrorBuf *bytes.Buffer
 
-	args          []string                 // actual args parsed from flags
-	output        *io.Writer               // out writer if set in SetOutput(w)
-	usageFunc     func(*Command) error     // Usage can be defined by application
-	usageTemplate string                   // Can be defined by Application
+	args          []string             // actual args parsed from flags
+	output        *io.Writer           // out writer if set in SetOutput(w)
+	usageFunc     func(*Command) error // Usage can be defined by application
+	usageTemplate string               // Can be defined by Application
+	flagErrorFunc func(*Command, error) error
 	helpTemplate  string                   // Can be defined by Application
 	helpFunc      func(*Command, []string) // Help can be defined by application
 	helpCommand   *Command                 // The help command
@@ -128,7 +132,7 @@ type Command struct {
 	DisableFlagParsing bool
 }
 
-// os.Args[1:] by default, if desired, can be overridden
+// SetArgs sets arguments for the command. It is set to os.Args[1:] by default, if desired, can be overridden
 // particularly useful when testing.
 func (c *Command) SetArgs(a []string) {
 	c.args = a
@@ -140,26 +144,33 @@ func (c *Command) SetOutput(output io.Writer) {
 	c.output = &output
 }
 
-// Usage can be defined by application
+// SetUsageFunc sets usage function. Usage can be defined by application.
 func (c *Command) SetUsageFunc(f func(*Command) error) {
 	c.usageFunc = f
 }
 
-// Can be defined by Application
+// SetUsageTemplate sets usage template. Can be defined by Application.
 func (c *Command) SetUsageTemplate(s string) {
 	c.usageTemplate = s
 }
 
-// Can be defined by Application
+// SetFlagErrorFunc sets a function to generate an error when flag parsing
+// fails.
+func (c *Command) SetFlagErrorFunc(f func(*Command, error) error) {
+	c.flagErrorFunc = f
+}
+
+// SetHelpFunc sets help function. Can be defined by Application.
 func (c *Command) SetHelpFunc(f func(*Command, []string)) {
 	c.helpFunc = f
 }
 
+// SetHelpCommand sets help command.
 func (c *Command) SetHelpCommand(cmd *Command) {
 	c.helpCommand = cmd
 }
 
-// Can be defined by Application
+// SetHelpTemplate sets help template to be used. Application can use it to set custom template.
 func (c *Command) SetHelpTemplate(s string) {
 	c.helpTemplate = s
 }
@@ -176,10 +187,12 @@ func (c *Command) SetGlobalNormalizationFunc(n func(f *flag.FlagSet, name string
 	}
 }
 
+// OutOrStdout returns output to stdout.
 func (c *Command) OutOrStdout() io.Writer {
 	return c.getOut(os.Stdout)
 }
 
+// OutOrStderr returns output to stderr
 func (c *Command) OutOrStderr() io.Writer {
 	return c.getOut(os.Stderr)
 }
@@ -195,7 +208,7 @@ func (c *Command) getOut(def io.Writer) io.Writer {
 }
 
 // UsageFunc returns either the function set by SetUsageFunc for this command
-// or a parent, or it returns a default usage function
+// or a parent, or it returns a default usage function.
 func (c *Command) UsageFunc() (f func(*Command) error) {
 	if c.usageFunc != nil {
 		return c.usageFunc
@@ -214,15 +227,18 @@ func (c *Command) UsageFunc() (f func(*Command) error) {
 	}
 }
 
+// Usage puts out the usage for the command.
+// Used when a user provides invalid input.
+// Can be defined by user by overriding UsageFunc.
+func (c *Command) Usage() error {
+	return c.UsageFunc()(c)
+}
+
 // HelpFunc returns either the function set by SetHelpFunc for this command
-// or a parent, or it returns a function with default help behavior
+// or a parent, or it returns a function with default help behavior.
 func (c *Command) HelpFunc() func(*Command, []string) {
-	cmd := c
-	for cmd != nil {
-		if cmd.helpFunc != nil {
-			return cmd.helpFunc
-		}
-		cmd = cmd.parent
+	if helpFunc := c.checkHelpFunc(); helpFunc != nil {
+		return helpFunc
 	}
 	return func(*Command, []string) {
 		c.mergePersistentFlags()
@@ -233,17 +249,57 @@ func (c *Command) HelpFunc() func(*Command, []string) {
 	}
 }
 
+// checkHelpFunc checks if there is helpFunc in ancestors of c.
+func (c *Command) checkHelpFunc() func(*Command, []string) {
+	if c == nil {
+		return nil
+	}
+	if c.helpFunc != nil {
+		return c.helpFunc
+	}
+	if c.HasParent() {
+		return c.parent.checkHelpFunc()
+	}
+	return nil
+}
+
+// Help puts out the help for the command.
+// Used when a user calls help [command].
+// Can be defined by user by overriding HelpFunc.
+func (c *Command) Help() error {
+	c.HelpFunc()(c, []string{})
+	return nil
+}
+
+// UsageString return usage string.
 func (c *Command) UsageString() string {
 	tmpOutput := c.output
 	bb := new(bytes.Buffer)
 	c.SetOutput(bb)
-	c.UsageFunc()(c)
+	c.Usage()
 	c.output = tmpOutput
 	return bb.String()
 }
 
+// FlagErrorFunc returns either the function set by SetFlagErrorFunc for this
+// command or a parent, or it returns a function which returns the original
+// error.
+func (c *Command) FlagErrorFunc() (f func(*Command, error) error) {
+	if c.flagErrorFunc != nil {
+		return c.flagErrorFunc
+	}
+
+	if c.HasParent() {
+		return c.parent.FlagErrorFunc()
+	}
+	return func(c *Command, err error) error {
+		return err
+	}
+}
+
 var minUsagePadding = 25
 
+// UsagePadding return padding for the usage.
 func (c *Command) UsagePadding() int {
 	if c.parent == nil || minUsagePadding > c.parent.commandsMaxUseLen {
 		return minUsagePadding
@@ -253,7 +309,7 @@ func (c *Command) UsagePadding() int {
 
 var minCommandPathPadding = 11
 
-//
+// CommandPathPadding return padding for the command path.
 func (c *Command) CommandPathPadding() int {
 	if c.parent == nil || minCommandPathPadding > c.parent.commandsMaxCommandPathLen {
 		return minCommandPathPadding
@@ -263,6 +319,7 @@ func (c *Command) CommandPathPadding() int {
 
 var minNamePadding = 11
 
+// NamePadding returns padding for the name.
 func (c *Command) NamePadding() int {
 	if c.parent == nil || minNamePadding > c.parent.commandsMaxNameLen {
 		return minNamePadding
@@ -270,6 +327,7 @@ func (c *Command) NamePadding() int {
 	return c.parent.commandsMaxNameLen
 }
 
+// UsageTemplate returns usage template for the command.
 func (c *Command) UsageTemplate() string {
 	if c.usageTemplate != "" {
 		return c.usageTemplate
@@ -287,24 +345,25 @@ Aliases:
 {{end}}{{if .HasExample}}
 
 Examples:
-{{ .Example }}{{end}}{{ if .HasAvailableSubCommands}}
+{{ .Example }}{{end}}{{if .HasAvailableSubCommands}}
 
-Available Commands:{{range .Commands}}{{if .IsAvailableCommand}}
-  {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{end}}{{ if .HasAvailableLocalFlags}}
+Available Commands:{{range .Commands}}{{if (or .IsAvailableCommand (eq .Name "help"))}}
+  {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{end}}{{if .HasAvailableLocalFlags}}
 
 Flags:
-{{.LocalFlags.FlagUsages | trimRightSpace}}{{end}}{{ if .HasAvailableInheritedFlags}}
+{{.LocalFlags.FlagUsages | trimRightSpace}}{{end}}{{if .HasAvailableInheritedFlags}}
 
 Global Flags:
 {{.InheritedFlags.FlagUsages | trimRightSpace}}{{end}}{{if .HasHelpSubCommands}}
 
-Additional help topics:{{range .Commands}}{{if .IsHelpCommand}}
-  {{rpad .CommandPath .CommandPathPadding}} {{.Short}}{{end}}{{end}}{{end}}{{ if .HasAvailableSubCommands }}
+Additional help topics:{{range .Commands}}{{if .IsAdditionalHelpTopicCommand}}
+  {{rpad .CommandPath .CommandPathPadding}} {{.Short}}{{end}}{{end}}{{end}}{{if .HasAvailableSubCommands}}
 
 Use "{{.CommandPath}} [command] --help" for more information about a command.{{end}}
 `
 }
 
+// HelpTemplate return help template for the command.
 func (c *Command) HelpTemplate() string {
 	if c.helpTemplate != "" {
 		return c.helpTemplate
@@ -318,27 +377,25 @@ func (c *Command) HelpTemplate() string {
 {{end}}{{if or .Runnable .HasSubCommands}}{{.UsageString}}{{end}}`
 }
 
-// Really only used when casting a command to a commander
+// Really only used when casting a command to a commander.
 func (c *Command) resetChildrensParents() {
 	for _, x := range c.commands {
 		x.parent = c
 	}
 }
 
-// Test if the named flag is a boolean flag.
-func isBooleanFlag(name string, f *flag.FlagSet) bool {
+func hasNoOptDefVal(name string, f *flag.FlagSet) bool {
 	flag := f.Lookup(name)
 	if flag == nil {
 		return false
 	}
-	return flag.Value.Type() == "bool"
+	return len(flag.NoOptDefVal) > 0
 }
 
-// Test if the named flag is a boolean flag.
-func isBooleanShortFlag(name string, f *flag.FlagSet) bool {
+func shortHasNoOptDefVal(name string, fs *flag.FlagSet) bool {
 	result := false
-	f.VisitAll(func(f *flag.Flag) {
-		if f.Shorthand == name && f.Value.Type() == "bool" {
+	fs.VisitAll(func(flag *flag.Flag) {
+		if flag.Shorthand == name && len(flag.NoOptDefVal) > 0 {
 			result = true
 		}
 	})
@@ -364,13 +421,13 @@ func stripFlags(args []string, c *Command) []string {
 				inQuote = true
 			case strings.HasPrefix(y, "--") && !strings.Contains(y, "="):
 				// TODO: this isn't quite right, we should really check ahead for 'true' or 'false'
-				inFlag = !isBooleanFlag(y[2:], c.Flags())
-			case strings.HasPrefix(y, "-") && !strings.Contains(y, "=") && len(y) == 2 && !isBooleanShortFlag(y[1:], c.Flags()):
+				inFlag = !hasNoOptDefVal(y[2:], c.Flags())
+			case strings.HasPrefix(y, "-") && !strings.Contains(y, "=") && len(y) == 2 && !shortHasNoOptDefVal(y[1:], c.Flags()):
 				inFlag = true
 			case inFlag:
 				inFlag = false
 			case y == "":
-				// strip empty commands, as the go tests expect this to be ok....
+			// strip empty commands, as the go tests expect this to be ok....
 			case !strings.HasPrefix(y, "-"):
 				commands = append(commands, y)
 				inFlag = false
@@ -399,7 +456,7 @@ func argsMinusFirstX(args []string, x string) []string {
 	return args
 }
 
-// find the target command given the args and command tree
+// Find the target command given the args and command tree
 // Meant to be run on the highest node. Only searches down.
 func (c *Command) Find(args []string) (*Command, []string, error) {
 	if c == nil {
@@ -467,6 +524,7 @@ func (c *Command) Find(args []string) (*Command, []string, error) {
 	return commandFound, a, nil
 }
 
+// SuggestionsFor provides suggestions for the typedName.
 func (c *Command) SuggestionsFor(typedName string) []string {
 	suggestions := []string{}
 	for _, cmd := range c.commands {
@@ -487,6 +545,7 @@ func (c *Command) SuggestionsFor(typedName string) []string {
 	return suggestions
 }
 
+// VisitParents visits all parents of the command and invokes fn on each parent.
 func (c *Command) VisitParents(fn func(*Command)) {
 	var traverse func(*Command) *Command
 
@@ -502,6 +561,7 @@ func (c *Command) VisitParents(fn func(*Command)) {
 	traverse(c)
 }
 
+// Root finds root command.
 func (c *Command) Root() *Command {
 	var findRoot func(*Command) *Command
 
@@ -538,7 +598,7 @@ func (c *Command) execute(a []string) (err error) {
 
 	err = c.ParseFlags(a)
 	if err != nil {
-		return err
+		return c.FlagErrorFunc()(c, err)
 	}
 	// If help is called, regardless of other flags, return we want help
 	// Also say we need help if the command isn't runnable.
@@ -626,7 +686,7 @@ func (c *Command) errorMsgFromParse() string {
 	return ""
 }
 
-// Call execute to use the args (os.Args[1:] by default)
+// Execute Call execute to use the args (os.Args[1:] by default)
 // and run through the command tree finding appropriate matches
 // for commands and then corresponding flags.
 func (c *Command) Execute() error {
@@ -634,8 +694,8 @@ func (c *Command) Execute() error {
 	return err
 }
 
+// ExecuteC executes the command.
 func (c *Command) ExecuteC() (cmd *Command, err error) {
-
 	// Regardless of what command execute is called on, run on Root only
 	if c.HasParent() {
 		return c.Root().ExecuteC()
@@ -697,6 +757,7 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 }
 
 func (c *Command) initHelpFlag() {
+	c.mergePersistentFlags()
 	if c.Flags().Lookup("help") == nil {
 		c.Flags().BoolP("help", "h", false, "help for "+c.Name())
 	}
@@ -719,10 +780,10 @@ func (c *Command) initHelpCmd() {
 			Run: func(c *Command, args []string) {
 				cmd, _, e := c.Root().Find(args)
 				if cmd == nil || e != nil {
-					c.Printf("Unknown help topic %#q.", args)
-					c.Root().UsageFunc()(cmd)
+					c.Printf("Unknown help topic %#q\n", args)
+					c.Root().Usage()
 				} else {
-					cmd.HelpFunc()(cmd, args)
+					cmd.Help()
 				}
 			},
 		}
@@ -730,13 +791,13 @@ func (c *Command) initHelpCmd() {
 	c.AddCommand(c.helpCommand)
 }
 
-// Used for testing
+// ResetCommands used for testing.
 func (c *Command) ResetCommands() {
 	c.commands = nil
 	c.helpCommand = nil
 }
 
-// Sorts commands by their names
+// Sorts commands by their names.
 type commandSorterByName []*Command
 
 func (c commandSorterByName) Len() int           { return len(c) }
@@ -816,18 +877,18 @@ main:
 	}
 }
 
-// Print is a convenience method to Print to the defined output, fallback to Stderr if not set
+// Print is a convenience method to Print to the defined output, fallback to Stderr if not set.
 func (c *Command) Print(i ...interface{}) {
 	fmt.Fprint(c.OutOrStderr(), i...)
 }
 
-// Println is a convenience method to Println to the defined output, fallback to Stderr if not set
+// Println is a convenience method to Println to the defined output, fallback to Stderr if not set.
 func (c *Command) Println(i ...interface{}) {
 	str := fmt.Sprintln(i...)
 	c.Print(str)
 }
 
-// Printf is a convenience method to Printf to the defined output, fallback to Stderr if not set
+// Printf is a convenience method to Printf to the defined output, fallback to Stderr if not set.
 func (c *Command) Printf(format string, i ...interface{}) {
 	str := fmt.Sprintf(format, i...)
 	c.Print(str)
@@ -844,7 +905,7 @@ func (c *Command) CommandPath() string {
 	return str
 }
 
-//The full usage for a given command (including parents)
+// UseLine puts out the full usage for a given command (including parents).
 func (c *Command) UseLine() string {
 	str := ""
 	if c.HasParent() {
@@ -853,8 +914,8 @@ func (c *Command) UseLine() string {
 	return str + c.Use
 }
 
-// For use in determining which flags have been assigned to which commands
-// and which persist
+// DebugFlags used to determine which flags have been assigned to which commands
+// and which persist.
 func (c *Command) DebugFlags() {
 	c.Println("DebugFlags called on", c.Name())
 	var debugflags func(*Command)
@@ -908,7 +969,8 @@ func (c *Command) Name() string {
 	if i >= 0 {
 		name = name[:i]
 	}
-	return name
+	c.name = name
+	return c.name
 }
 
 // HasAlias determines if a given string is an alias of the command.
@@ -921,26 +983,28 @@ func (c *Command) HasAlias(s string) bool {
 	return false
 }
 
+// NameAndAliases returns string containing name and all aliases
 func (c *Command) NameAndAliases() string {
 	return strings.Join(append([]string{c.Name()}, c.Aliases...), ", ")
 }
 
+// HasExample determines if the command has example.
 func (c *Command) HasExample() bool {
 	return len(c.Example) > 0
 }
 
-// Runnable determines if the command is itself runnable
+// Runnable determines if the command is itself runnable.
 func (c *Command) Runnable() bool {
 	return c.Run != nil || c.RunE != nil
 }
 
-// HasSubCommands determines if the command has children commands
+// HasSubCommands determines if the command has children commands.
 func (c *Command) HasSubCommands() bool {
 	return len(c.commands) > 0
 }
 
 // IsAvailableCommand determines if a command is available as a non-help command
-// (this includes all non deprecated/hidden commands)
+// (this includes all non deprecated/hidden commands).
 func (c *Command) IsAvailableCommand() bool {
 	if len(c.Deprecated) != 0 || c.Hidden {
 		return false
@@ -957,11 +1021,12 @@ func (c *Command) IsAvailableCommand() bool {
 	return false
 }
 
-// IsHelpCommand determines if a command is a 'help' command; a help command is
-// determined by the fact that it is NOT runnable/hidden/deprecated, and has no
-// sub commands that are runnable/hidden/deprecated
-func (c *Command) IsHelpCommand() bool {
-
+// IsAdditionalHelpTopicCommand determines if a command is an additional
+// help topic command; additional help topic command is determined by the
+// fact that it is NOT runnable/hidden/deprecated, and has no sub commands that
+// are runnable/hidden/deprecated.
+// Concrete example: https://github.com/spf13/cobra/issues/393#issuecomment-282741924.
+func (c *Command) IsAdditionalHelpTopicCommand() bool {
 	// if a command is runnable, deprecated, or hidden it is not a 'help' command
 	if c.Runnable() || len(c.Deprecated) != 0 || c.Hidden {
 		return false
@@ -969,7 +1034,7 @@ func (c *Command) IsHelpCommand() bool {
 
 	// if any non-help sub commands are found, the command is not a 'help' command
 	for _, sub := range c.commands {
-		if !sub.IsHelpCommand() {
+		if !sub.IsAdditionalHelpTopicCommand() {
 			return false
 		}
 	}
@@ -978,14 +1043,13 @@ func (c *Command) IsHelpCommand() bool {
 	return true
 }
 
-// HasHelpSubCommands determines if a command has any avilable 'help' sub commands
+// HasHelpSubCommands determines if a command has any available 'help' sub commands
 // that need to be shown in the usage/help default template under 'additional help
-// topics'
+// topics'.
 func (c *Command) HasHelpSubCommands() bool {
-
 	// return true on the first found available 'help' sub command
 	for _, sub := range c.commands {
-		if sub.IsHelpCommand() {
+		if sub.IsAdditionalHelpTopicCommand() {
 			return true
 		}
 	}
@@ -995,9 +1059,8 @@ func (c *Command) HasHelpSubCommands() bool {
 }
 
 // HasAvailableSubCommands determines if a command has available sub commands that
-// need to be shown in the usage/help default template under 'available commands'
+// need to be shown in the usage/help default template under 'available commands'.
 func (c *Command) HasAvailableSubCommands() bool {
-
 	// return true on the first found available (non deprecated/help/hidden)
 	// sub command
 	for _, sub := range c.commands {
@@ -1011,17 +1074,18 @@ func (c *Command) HasAvailableSubCommands() bool {
 	return false
 }
 
-// Determine if the command is a child command
+// HasParent determines if the command is a child command.
 func (c *Command) HasParent() bool {
 	return c.parent != nil
 }
 
-// GlobalNormalizationFunc returns the global normalization function or nil if doesn't exists
+// GlobalNormalizationFunc returns the global normalization function or nil if doesn't exists.
 func (c *Command) GlobalNormalizationFunc() func(f *flag.FlagSet, name string) flag.NormalizedName {
 	return c.globNormFunc
 }
 
-// Get the complete FlagSet that applies to this command (local and persistent declared here and by all parents)
+// Flags returns the complete FlagSet that applies
+// to this command (local and persistent declared here and by all parents).
 func (c *Command) Flags() *flag.FlagSet {
 	if c.flags == nil {
 		c.flags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
@@ -1033,7 +1097,7 @@ func (c *Command) Flags() *flag.FlagSet {
 	return c.flags
 }
 
-// LocalNonPersistentFlags are flags specific to this command which will NOT persist to subcommands
+// LocalNonPersistentFlags are flags specific to this command which will NOT persist to subcommands.
 func (c *Command) LocalNonPersistentFlags() *flag.FlagSet {
 	persistentFlags := c.PersistentFlags()
 
@@ -1046,7 +1110,7 @@ func (c *Command) LocalNonPersistentFlags() *flag.FlagSet {
 	return out
 }
 
-// Get the local FlagSet specifically set in the current command
+// LocalFlags returns the local FlagSet specifically set in the current command.
 func (c *Command) LocalFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
@@ -1064,7 +1128,7 @@ func (c *Command) LocalFlags() *flag.FlagSet {
 	return local
 }
 
-// All Flags which were inherited from parents commands
+// InheritedFlags returns all flags which were inherited from parents commands.
 func (c *Command) InheritedFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
@@ -1093,12 +1157,12 @@ func (c *Command) InheritedFlags() *flag.FlagSet {
 	return inherited
 }
 
-// All Flags which were not inherited from parent commands
+// NonInheritedFlags returns all flags which were not inherited from parent commands.
 func (c *Command) NonInheritedFlags() *flag.FlagSet {
 	return c.LocalFlags()
 }
 
-// Get the Persistent FlagSet specifically set in the current command
+// PersistentFlags returns the persistent FlagSet specifically set in the current command.
 func (c *Command) PersistentFlags() *flag.FlagSet {
 	if c.pflags == nil {
 		c.pflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
@@ -1110,7 +1174,7 @@ func (c *Command) PersistentFlags() *flag.FlagSet {
 	return c.pflags
 }
 
-// For use in testing
+// ResetFlags is used in testing.
 func (c *Command) ResetFlags() {
 	c.flagErrorBuf = new(bytes.Buffer)
 	c.flagErrorBuf.Reset()
@@ -1120,50 +1184,50 @@ func (c *Command) ResetFlags() {
 	c.pflags.SetOutput(c.flagErrorBuf)
 }
 
-// Does the command contain any flags (local plus persistent from the entire structure)
+// HasFlags checks if the command contains any flags (local plus persistent from the entire structure).
 func (c *Command) HasFlags() bool {
 	return c.Flags().HasFlags()
 }
 
-// Does the command contain persistent flags
+// HasPersistentFlags checks if the command contains persistent flags.
 func (c *Command) HasPersistentFlags() bool {
 	return c.PersistentFlags().HasFlags()
 }
 
-// Does the command has flags specifically declared locally
+// HasLocalFlags checks if the command has flags specifically declared locally.
 func (c *Command) HasLocalFlags() bool {
 	return c.LocalFlags().HasFlags()
 }
 
-// Does the command have flags inherited from its parent command
+// HasInheritedFlags checks if the command has flags inherited from its parent command.
 func (c *Command) HasInheritedFlags() bool {
 	return c.InheritedFlags().HasFlags()
 }
 
-// Does the command contain any flags (local plus persistent from the entire
-// structure) which are not hidden or deprecated
+// HasAvailableFlags checks if the command contains any flags (local plus persistent from the entire
+// structure) which are not hidden or deprecated.
 func (c *Command) HasAvailableFlags() bool {
 	return c.Flags().HasAvailableFlags()
 }
 
-// Does the command contain persistent flags which are not hidden or deprecated
+// HasAvailablePersistentFlags checks if the command contains persistent flags which are not hidden or deprecated.
 func (c *Command) HasAvailablePersistentFlags() bool {
 	return c.PersistentFlags().HasAvailableFlags()
 }
 
-// Does the command has flags specifically declared locally which are not hidden
-// or deprecated
+// HasAvailableLocalFlags checks if the command has flags specifically declared locally which are not hidden
+// or deprecated.
 func (c *Command) HasAvailableLocalFlags() bool {
 	return c.LocalFlags().HasAvailableFlags()
 }
 
-// Does the command have flags inherited from its parent command which are
-// not hidden or deprecated
+// HasAvailableInheritedFlags checks if the command has flags inherited from its parent command which are
+// not hidden or deprecated.
 func (c *Command) HasAvailableInheritedFlags() bool {
 	return c.InheritedFlags().HasAvailableFlags()
 }
 
-// Flag climbs up the command tree looking for matching flag
+// Flag climbs up the command tree looking for matching flag.
 func (c *Command) Flag(name string) (flag *flag.Flag) {
 	flag = c.Flags().Lookup(name)
 
@@ -1174,7 +1238,7 @@ func (c *Command) Flag(name string) (flag *flag.Flag) {
 	return
 }
 
-// recursively find matching persistent flag
+// Recursively find matching persistent flag.
 func (c *Command) persistentFlag(name string) (flag *flag.Flag) {
 	if c.HasPersistentFlags() {
 		flag = c.PersistentFlags().Lookup(name)
@@ -1186,7 +1250,7 @@ func (c *Command) persistentFlag(name string) (flag *flag.Flag) {
 	return
 }
 
-// ParseFlags parses persistent flag tree & local flags
+// ParseFlags parses persistent flag tree and local flags.
 func (c *Command) ParseFlags(args []string) (err error) {
 	if c.DisableFlagParsing {
 		return nil
@@ -1196,7 +1260,7 @@ func (c *Command) ParseFlags(args []string) (err error) {
 	return
 }
 
-// Parent returns a commands parent command
+// Parent returns a commands parent command.
 func (c *Command) Parent() *Command {
 	return c.parent
 }
diff --git a/doc/man_docs.go b/doc/man_docs.go
index b202029..b9266c3 100644
--- a/doc/man_docs.go
+++ b/doc/man_docs.go
@@ -37,7 +37,7 @@ func GenManTree(cmd *cobra.Command, header *GenManHeader, dir string) error {
 	return GenManTreeFromOpts(cmd, GenManTreeOptions{
 		Header:           header,
 		Path:             dir,
-		CommandSeparator: "_",
+		CommandSeparator: "-",
 	})
 }
 
@@ -49,7 +49,7 @@ func GenManTreeFromOpts(cmd *cobra.Command, opts GenManTreeOptions) error {
 		header = &GenManHeader{}
 	}
 	for _, c := range cmd.Commands() {
-		if !c.IsAvailableCommand() || c.IsHelpCommand() {
+		if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
 			continue
 		}
 		if err := GenManTreeFromOpts(c, opts); err != nil {
@@ -66,7 +66,7 @@ func GenManTreeFromOpts(cmd *cobra.Command, opts GenManTreeOptions) error {
 		separator = opts.CommandSeparator
 	}
 	basename := strings.Replace(cmd.CommandPath(), " ", separator, -1)
-	filename := filepath.Join(opts.Path, basename + "." + section)
+	filename := filepath.Join(opts.Path, basename+"."+section)
 	f, err := os.Create(filename)
 	if err != nil {
 		return err
@@ -216,7 +216,7 @@ func genMan(cmd *cobra.Command, header *GenManHeader) []byte {
 		children := cmd.Commands()
 		sort.Sort(byName(children))
 		for _, c := range children {
-			if !c.IsAvailableCommand() || c.IsHelpCommand() {
+			if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
 				continue
 			}
 			seealso := fmt.Sprintf("**%s-%s(%s)**", dashCommandName, c.Name(), header.Section)
diff --git a/doc/man_docs.md b/doc/man_docs.md
index 5fe957a..d568d9a 100644
--- a/doc/man_docs.md
+++ b/doc/man_docs.md
@@ -15,7 +15,7 @@ func main() {
 		Use:   "test",
 		Short: "my test program",
 	}
-	header := &cobra.GenManHeader{
+	header := &doc.GenManHeader{
 		Title: "MINE",
 		Section: "3",
 	}
@@ -23,4 +23,4 @@ func main() {
 }
 ```
 
-That will get you a man page `/tmp/test.1`
+That will get you a man page `/tmp/test.3`
diff --git a/doc/md_docs.go b/doc/md_docs.go
index fa13631..8d159c1 100644
--- a/doc/md_docs.go
+++ b/doc/md_docs.go
@@ -119,7 +119,7 @@ func GenMarkdownCustom(cmd *cobra.Command, w io.Writer, linkHandler func(string)
 		sort.Sort(byName(children))
 
 		for _, child := range children {
-			if !child.IsAvailableCommand() || child.IsHelpCommand() {
+			if !child.IsAvailableCommand() || child.IsAdditionalHelpTopicCommand() {
 				continue
 			}
 			cname := name + " " + child.Name()
@@ -149,7 +149,7 @@ func GenMarkdownTree(cmd *cobra.Command, dir string) error {
 
 func GenMarkdownTreeCustom(cmd *cobra.Command, dir string, filePrepender, linkHandler func(string) string) error {
 	for _, c := range cmd.Commands() {
-		if !c.IsAvailableCommand() || c.IsHelpCommand() {
+		if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
 			continue
 		}
 		if err := GenMarkdownTreeCustom(c, dir, filePrepender, linkHandler); err != nil {
diff --git a/doc/md_docs.md b/doc/md_docs.md
index 0c3b96e..beec3e0 100644
--- a/doc/md_docs.md
+++ b/doc/md_docs.md
@@ -32,15 +32,15 @@ import (
 	"io/ioutil"
 	"os"
 
-	kubectlcmd "k8s.io/kubernetes/pkg/kubectl/cmd"
+	"k8s.io/kubernetes/pkg/kubectl/cmd"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
 
 	"github.com/spf13/cobra/doc"
 )
 
 func main() {
-	cmd := kubectlcmd.NewKubectlCommand(cmdutil.NewFactory(nil), os.Stdin, ioutil.Discard, ioutil.Discard)
-	doc.GenMarkdownTree(cmd, "./")
+	kubectl := cmd.NewKubectlCommand(cmdutil.NewFactory(nil), os.Stdin, ioutil.Discard, ioutil.Discard)
+	doc.GenMarkdownTree(kubectl, "./")
 }
 ```
 
@@ -101,4 +101,3 @@ linkHandler := func(name string) string {
 	return "/commands/" + strings.ToLower(base) + "/"
 }
 ```
-
diff --git a/doc/util.go b/doc/util.go
index a1c6b89..8d3dbec 100644
--- a/doc/util.go
+++ b/doc/util.go
@@ -13,7 +13,11 @@
 
 package doc
 
-import "github.com/spf13/cobra"
+import (
+	"strings"
+
+	"github.com/spf13/cobra"
+)
 
 // Test to see if we have a reason to print See Also information in docs
 // Basically this is a test for a parent commend or a subcommand which is
@@ -23,7 +27,7 @@ func hasSeeAlso(cmd *cobra.Command) bool {
 		return true
 	}
 	for _, c := range cmd.Commands() {
-		if !c.IsAvailableCommand() || c.IsHelpCommand() {
+		if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
 			continue
 		}
 		return true
@@ -31,6 +35,15 @@ func hasSeeAlso(cmd *cobra.Command) bool {
 	return false
 }
 
+// Temporary workaround for yaml lib generating incorrect yaml with long strings
+// that do not contain \n.
+func forceMultiLine(s string) string {
+	if len(s) > 60 && !strings.Contains(s, "\n") {
+		s = s + "\n"
+	}
+	return s
+}
+
 type byName []*cobra.Command
 
 func (s byName) Len() int           { return len(s) }
diff --git a/doc/yaml_docs.go b/doc/yaml_docs.go
new file mode 100644
index 0000000..ac8db89
--- /dev/null
+++ b/doc/yaml_docs.go
@@ -0,0 +1,165 @@
+// Copyright 2016 French Ben. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package doc
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"gopkg.in/yaml.v2"
+)
+
+type cmdOption struct {
+	Name         string
+	Shorthand    string `yaml:",omitempty"`
+	DefaultValue string `yaml:"default_value,omitempty"`
+	Usage        string `yaml:",omitempty"`
+}
+
+type cmdDoc struct {
+	Name             string
+	Synopsis         string      `yaml:",omitempty"`
+	Description      string      `yaml:",omitempty"`
+	Options          []cmdOption `yaml:",omitempty"`
+	InheritedOptions []cmdOption `yaml:"inherited_options,omitempty"`
+	Example          string      `yaml:",omitempty"`
+	SeeAlso          []string    `yaml:"see_also,omitempty"`
+}
+
+// GenYamlTree creates yaml structured ref files for this command and all descendants
+// in the directory given. This function may not work
+// correctly if your command names have - in them. If you have `cmd` with two
+// subcmds, `sub` and `sub-third`. And `sub` has a subcommand called `third`
+// it is undefined which help output will be in the file `cmd-sub-third.1`.
+func GenYamlTree(cmd *cobra.Command, dir string) error {
+	identity := func(s string) string { return s }
+	emptyStr := func(s string) string { return "" }
+	return GenYamlTreeCustom(cmd, dir, emptyStr, identity)
+}
+
+// GenYamlTreeCustom creates yaml structured ref files
+func GenYamlTreeCustom(cmd *cobra.Command, dir string, filePrepender, linkHandler func(string) string) error {
+	for _, c := range cmd.Commands() {
+		if !c.IsAvailableCommand() || c.IsAdditionalHelpTopicCommand() {
+			continue
+		}
+		if err := GenYamlTreeCustom(c, dir, filePrepender, linkHandler); err != nil {
+			return err
+		}
+	}
+
+	basename := strings.Replace(cmd.CommandPath(), " ", "_", -1) + ".yaml"
+	filename := filepath.Join(dir, basename)
+	f, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if _, err := io.WriteString(f, filePrepender(filename)); err != nil {
+		return err
+	}
+	if err := GenYamlCustom(cmd, f, linkHandler); err != nil {
+		return err
+	}
+	return nil
+}
+
+// GenYaml creates yaml output
+func GenYaml(cmd *cobra.Command, w io.Writer) error {
+	return GenYamlCustom(cmd, w, func(s string) string { return s })
+}
+
+// GenYamlCustom creates custom yaml output
+func GenYamlCustom(cmd *cobra.Command, w io.Writer, linkHandler func(string) string) error {
+	yamlDoc := cmdDoc{}
+	yamlDoc.Name = cmd.CommandPath()
+
+	yamlDoc.Synopsis = forceMultiLine(cmd.Short)
+	yamlDoc.Description = forceMultiLine(cmd.Long)
+
+	if len(cmd.Example) > 0 {
+		yamlDoc.Example = cmd.Example
+	}
+
+	flags := cmd.NonInheritedFlags()
+	if flags.HasFlags() {
+		yamlDoc.Options = genFlagResult(flags)
+	}
+	flags = cmd.InheritedFlags()
+	if flags.HasFlags() {
+		yamlDoc.InheritedOptions = genFlagResult(flags)
+	}
+
+	if hasSeeAlso(cmd) {
+		result := []string{}
+		if cmd.HasParent() {
+			parent := cmd.Parent()
+			result = append(result, parent.CommandPath()+" - "+parent.Short)
+		}
+		children := cmd.Commands()
+		sort.Sort(byName(children))
+		for _, child := range children {
+			if !child.IsAvailableCommand() || child.IsAdditionalHelpTopicCommand() {
+				continue
+			}
+			result = append(result, child.Name()+" - "+child.Short)
+		}
+		yamlDoc.SeeAlso = result
+	}
+
+	final, err := yaml.Marshal(&yamlDoc)
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	if _, err := fmt.Fprintf(w, string(final)); err != nil {
+		return err
+	}
+	return nil
+}
+
+func genFlagResult(flags *pflag.FlagSet) []cmdOption {
+	var result []cmdOption
+
+	flags.VisitAll(func(flag *pflag.Flag) {
+		// Todo, when we mark a shorthand is deprecated, but specify an empty message.
+		// The flag.ShorthandDeprecated is empty as the shorthand is deprecated.
+		// Using len(flag.ShorthandDeprecated) > 0 can't handle this, others are ok.
+		if !(len(flag.ShorthandDeprecated) > 0) && len(flag.Shorthand) > 0 {
+			opt := cmdOption{
+				flag.Name,
+				flag.Shorthand,
+				flag.DefValue,
+				forceMultiLine(flag.Usage),
+			}
+			result = append(result, opt)
+		} else {
+			opt := cmdOption{
+				Name:         flag.Name,
+				DefaultValue: forceMultiLine(flag.DefValue),
+				Usage:        forceMultiLine(flag.Usage),
+			}
+			result = append(result, opt)
+		}
+	})
+
+	return result
+}
diff --git a/doc/yaml_docs.md b/doc/yaml_docs.md
new file mode 100644
index 0000000..4d0c75a
--- /dev/null
+++ b/doc/yaml_docs.md
@@ -0,0 +1,103 @@
+# Generating Yaml Docs For Your Own cobra.Command
+
+Generating yaml files from a cobra command is incredibly easy. An example is as follows:
+
+```go
+package main
+
+import (
+	"github.com/spf13/cobra"
+	"github.com/spf13/cobra/doc"
+)
+
+func main() {
+	cmd := &cobra.Command{
+		Use:   "test",
+		Short: "my test program",
+	}
+	doc.GenYamlTree(cmd, "/tmp")
+}
+```
+
+That will get you a Yaml document `/tmp/test.yaml`
+
+## Generate yaml docs for the entire command tree
+
+This program can actually generate docs for the kubectl command in the kubernetes project
+
+```go
+package main
+
+import (
+	"io/ioutil"
+	"os"
+
+	"k8s.io/kubernetes/pkg/kubectl/cmd"
+	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+
+	"github.com/spf13/cobra/doc"
+)
+
+func main() {
+	kubectl := cmd.NewKubectlCommand(cmdutil.NewFactory(nil), os.Stdin, ioutil.Discard, ioutil.Discard)
+	doc.GenYamlTree(kubectl, "./")
+}
+```
+
+This will generate a whole series of files, one for each command in the tree, in the directory specified (in this case "./")
+
+## Generate yaml docs for a single command
+
+You may wish to have more control over the output, or only generate for a single command, instead of the entire command tree. If this is the case you may prefer to `GenYaml` instead of `GenYamlTree`
+
+```go
+	out := new(bytes.Buffer)
+	doc.GenYaml(cmd, out)
+```
+
+This will write the yaml doc for ONLY "cmd" into the out, buffer.
+
+## Customize the output
+
+Both `GenYaml` and `GenYamlTree` have alternate versions with callbacks to get some control of the output:
+
+```go
+func GenYamlTreeCustom(cmd *Command, dir string, filePrepender, linkHandler func(string) string) error {
+	//...
+}
+```
+
+```go
+func GenYamlCustom(cmd *Command, out *bytes.Buffer, linkHandler func(string) string) error {
+	//...
+}
+```
+
+The `filePrepender` will prepend the return value given the full filepath to the rendered Yaml file. A common use case is to add front matter to use the generated documentation with [Hugo](http://gohugo.io/):
+
+```go
+const fmTemplate = `---
+date: %s
+title: "%s"
+slug: %s
+url: %s
+---
+`
+
+filePrepender := func(filename string) string {
+	now := time.Now().Format(time.RFC3339)
+	name := filepath.Base(filename)
+	base := strings.TrimSuffix(name, path.Ext(name))
+	url := "/commands/" + strings.ToLower(base) + "/"
+	return fmt.Sprintf(fmTemplate, now, strings.Replace(base, "_", " ", -1), base, url)
+}
+```
+
+The `linkHandler` can be used to customize the rendered internal links to the commands, given a filename:
+
+```go
+linkHandler := func(name string) string {
+	base := strings.TrimSuffix(name, path.Ext(name))
+	return "/commands/" + strings.ToLower(base) + "/"
+}
+```


Test patch:
diff --git a/bash_completions_test.go b/bash_completions_test.go
index 6957f8b..185570b 100644
--- a/bash_completions_test.go
+++ b/bash_completions_test.go
@@ -138,3 +138,43 @@ func TestBashCompletions(t *testing.T) {
 		t.Fatalf("shellcheck failed: %v", err)
 	}
 }
+
+func TestBashCompletionHiddenFlag(t *testing.T) {
+	var cmdTrue = &Command{
+		Use: "does nothing",
+		Run: func(cmd *Command, args []string) {},
+	}
+
+	const flagName = "hidden-foo-bar-baz"
+
+	var flagValue bool
+	cmdTrue.Flags().BoolVar(&flagValue, flagName, false, "hidden flag")
+	cmdTrue.Flags().MarkHidden(flagName)
+
+	out := new(bytes.Buffer)
+	cmdTrue.GenBashCompletion(out)
+	bashCompletion := out.String()
+	if strings.Contains(bashCompletion, flagName) {
+		t.Errorf("expected completion to not include %q flag: Got %v", flagName, bashCompletion)
+	}
+}
+
+func TestBashCompletionDeprecatedFlag(t *testing.T) {
+	var cmdTrue = &Command{
+		Use: "does nothing",
+		Run: func(cmd *Command, args []string) {},
+	}
+
+	const flagName = "deprecated-foo-bar-baz"
+
+	var flagValue bool
+	cmdTrue.Flags().BoolVar(&flagValue, flagName, false, "hidden flag")
+	cmdTrue.Flags().MarkDeprecated(flagName, "use --does-not-exist instead")
+
+	out := new(bytes.Buffer)
+	cmdTrue.GenBashCompletion(out)
+	bashCompletion := out.String()
+	if strings.Contains(bashCompletion, flagName) {
+		t.Errorf("expected completion to not include %q flag: Got %v", flagName, bashCompletion)
+	}
+}
diff --git a/cobra_test.go b/cobra_test.go
index 881a621..46887fd 100644
--- a/cobra_test.go
+++ b/cobra_test.go
@@ -612,7 +612,7 @@ func TestSubcommandExecuteC(t *testing.T) {
 		Use: "echo message",
 		Run: func(c *Command, args []string) {
 			msg := strings.Join(args, " ")
-			c.Println(msg, msg)
+			c.Println(msg)
 		},
 	}
 
@@ -916,15 +916,14 @@ func TestRootUnknownCommand(t *testing.T) {
 
 func TestRootUnknownCommandSilenced(t *testing.T) {
 	r := noRRSetupTestSilenced("bogus")
-	s := "Run 'cobra-test --help' for usage.\n"
 
 	if r.Output != "" {
-		t.Errorf("Unexpected response.\nExpecting to be: \n\"\"\n Got:\n %q\n", s, r.Output)
+		t.Errorf("Unexpected response.\nExpecting to be: \n\"\"\n Got:\n %q\n", r.Output)
 	}
 
 	r = noRRSetupTestSilenced("--strtwo=a bogus")
 	if r.Output != "" {
-		t.Errorf("Unexpected response.\nExpecting to be:\n\"\"\nGot:\n %q\n", s, r.Output)
+		t.Errorf("Unexpected response.\nExpecting to be:\n\"\"\nGot:\n %q\n", r.Output)
 	}
 }
 
diff --git a/command_test.go b/command_test.go
index 127ca0e..7947f6c 100644
--- a/command_test.go
+++ b/command_test.go
@@ -1,6 +1,8 @@
 package cobra
 
 import (
+	"bytes"
+	"fmt"
 	"os"
 	"reflect"
 	"testing"
@@ -134,6 +136,20 @@ func Test_DisableFlagParsing(t *testing.T) {
 	}
 }
 
+func TestInitHelpFlagMergesFlags(t *testing.T) {
+	usage := "custom flag"
+	baseCmd := Command{Use: "testcmd"}
+	baseCmd.PersistentFlags().Bool("help", false, usage)
+	cmd := Command{Use: "do"}
+	baseCmd.AddCommand(&cmd)
+
+	cmd.initHelpFlag()
+	actual := cmd.Flags().Lookup("help").Usage
+	if actual != usage {
+		t.Fatalf("Expected the help flag from the base command with usage '%s', but got the default with usage '%s'", usage, actual)
+	}
+}
+
 func TestCommandsAreSorted(t *testing.T) {
 	EnableCommandSorting = true
 
@@ -142,11 +158,11 @@ func TestCommandsAreSorted(t *testing.T) {
 
 	var tmpCommand = &Command{Use: "tmp"}
 
-	for _, name := range(originalNames) {
+	for _, name := range originalNames {
 		tmpCommand.AddCommand(&Command{Use: name})
 	}
 
-	for i, c := range(tmpCommand.Commands()) {
+	for i, c := range tmpCommand.Commands() {
 		if expectedNames[i] != c.Name() {
 			t.Errorf("expected: %s, got: %s", expectedNames[i], c.Name())
 		}
@@ -162,11 +178,11 @@ func TestEnableCommandSortingIsDisabled(t *testing.T) {
 
 	var tmpCommand = &Command{Use: "tmp"}
 
-	for _, name := range(originalNames) {
+	for _, name := range originalNames {
 		tmpCommand.AddCommand(&Command{Use: name})
 	}
 
-	for i, c := range(tmpCommand.Commands()) {
+	for i, c := range tmpCommand.Commands() {
 		if originalNames[i] != c.Name() {
 			t.Errorf("expected: %s, got: %s", originalNames[i], c.Name())
 		}
@@ -174,3 +190,27 @@ func TestEnableCommandSortingIsDisabled(t *testing.T) {
 
 	EnableCommandSorting = true
 }
+
+func TestFlagErrorFunc(t *testing.T) {
+
+	cmd := &Command{
+		Use: "print",
+		RunE: func(cmd *Command, args []string) error {
+			return nil
+		},
+	}
+	expectedFmt := "This is expected: %s"
+
+	cmd.SetFlagErrorFunc(func(c *Command, err error) error {
+		return fmt.Errorf(expectedFmt, err)
+	})
+	cmd.SetArgs([]string{"--bogus-flag"})
+	cmd.SetOutput(new(bytes.Buffer))
+
+	err := cmd.Execute()
+
+	expected := fmt.Sprintf(expectedFmt, "unknown flag: --bogus-flag")
+	if err.Error() != expected {
+		t.Errorf("expected %v, got %v", expected, err.Error())
+	}
+}
diff --git a/doc/yaml_docs_test.go b/doc/yaml_docs_test.go
new file mode 100644
index 0000000..a41499e
--- /dev/null
+++ b/doc/yaml_docs_test.go
@@ -0,0 +1,88 @@
+package doc
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+)
+
+var _ = fmt.Println
+var _ = os.Stderr
+
+func TestGenYamlDoc(t *testing.T) {
+	c := initializeWithRootCmd()
+	// Need two commands to run the command alphabetical sort
+	cmdEcho.AddCommand(cmdTimes, cmdEchoSub, cmdDeprecated)
+	c.AddCommand(cmdPrint, cmdEcho)
+	cmdRootWithRun.PersistentFlags().StringVarP(&flags2a, "rootflag", "r", "two", strtwoParentHelp)
+
+	out := new(bytes.Buffer)
+
+	// We generate on s subcommand so we have both subcommands and parents
+	if err := GenYaml(cmdEcho, out); err != nil {
+		t.Fatal(err)
+	}
+	found := out.String()
+
+	// Our description
+	expected := cmdEcho.Long
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// Better have our example
+	expected = cmdEcho.Example
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// A local flag
+	expected = "boolone"
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// persistent flag on parent
+	expected = "rootflag"
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// We better output info about our parent
+	expected = cmdRootWithRun.Short
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	// And about subcommands
+	expected = cmdEchoSub.Short
+	if !strings.Contains(found, expected) {
+		t.Errorf("Unexpected response.\nExpecting to contain: \n %q\nGot:\n %q\n", expected, found)
+	}
+
+	unexpected := cmdDeprecated.Short
+	if strings.Contains(found, unexpected) {
+		t.Errorf("Unexpected response.\nFound: %v\nBut should not have!!\n", unexpected)
+	}
+}
+
+func TestGenYamlNoTag(t *testing.T) {
+	c := initializeWithRootCmd()
+	// Need two commands to run the command alphabetical sort
+	cmdEcho.AddCommand(cmdTimes, cmdEchoSub, cmdDeprecated)
+	c.AddCommand(cmdPrint, cmdEcho)
+	c.DisableAutoGenTag = true
+	cmdRootWithRun.PersistentFlags().StringVarP(&flags2a, "rootflag", "r", "two", strtwoParentHelp)
+	out := new(bytes.Buffer)
+
+	if err := GenYaml(c, out); err != nil {
+		t.Fatal(err)
+	}
+	found := out.String()
+
+	unexpected := "Auto generated"
+	checkStringOmits(t, found, unexpected)
+
+}