Repository: spf13/cobra
Pull request #873 (2019-06-04 04:26:11)

Update README.md
To avoid confusion, it is better to use `localCmd` instead of `rootCmd`

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Patch:
diff --git a/.gitignore b/.gitignore
index 1b8c7c2..3b053c5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,3 +34,5 @@ tags
 *.exe
 
 cobra.test
+
+.idea/*
diff --git a/README.md b/README.md
index ff16e3f..60c5a42 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,7 @@ Many of the most widely used Go projects are built using Cobra, such as:
 [Istio](https://istio.io),
 [Prototool](https://github.com/uber/prototool),
 [mattermost-server](https://github.com/mattermost/mattermost-server),
+[Gardener](https://github.com/gardener/gardenctl),
 etc.
 
 [![Build Status](https://travis-ci.org/spf13/cobra.svg "Travis CI status")](https://travis-ci.org/spf13/cobra)
@@ -48,6 +49,7 @@ etc.
   * [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)
+  * [Generating zsh completions](#generating-zsh-completions)
 - [Contributing](#contributing)
 - [License](#license)
 
@@ -336,7 +338,7 @@ rootCmd.PersistentFlags().BoolVarP(&Verbose, "verbose", "v", false, "verbose out
 A flag can also be assigned locally which will only apply to that specific command.
 
 ```go
-rootCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from")
+localCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from")
 ```
 
 ### Local Flag on Parent Commands
@@ -719,6 +721,11 @@ Cobra can generate documentation based on subcommands, flags, etc. in the follow
 
 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).
 
+## Generating zsh completions
+
+Cobra can generate zsh-completion file. Read more about it in
+[Zsh Completions](zsh_completions.md).
+
 # Contributing
 
 1. Fork it
diff --git a/bash_completions.go b/bash_completions.go
index c3c1e50..57bb8e1 100644
--- a/bash_completions.go
+++ b/bash_completions.go
@@ -545,51 +545,3 @@ func (c *Command) GenBashCompletionFile(filename string) error {
 
 	return c.GenBashCompletion(outFile)
 }
-
-// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
-// and causes your command to report an error if invoked without the flag.
-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,
-// and causes your command to report an error if invoked without the flag.
-func (c *Command) MarkPersistentFlagRequired(name string) error {
-	return MarkFlagRequired(c.PersistentFlags(), name)
-}
-
-// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
-// and causes your command to report an error if invoked without the flag.
-func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
-	return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"})
-}
-
-// 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 (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 (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 (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.
-// Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func MarkFlagFilename(flags *pflag.FlagSet, name string, extensions ...string) error {
-	return flags.SetAnnotation(name, BashCompFilenameExt, extensions)
-}
-
-// MarkFlagCustom adds the BashCompCustom annotation to the named flag in the flag set, if it exists.
-// Generated bash autocompletion will call the bash function f for the flag.
-func MarkFlagCustom(flags *pflag.FlagSet, name string, f string) error {
-	return flags.SetAnnotation(name, BashCompCustom, []string{f})
-}
diff --git a/cobra/cmd/add.go b/cobra/cmd/add.go
index fb22096..2d240b8 100644
--- a/cobra/cmd/add.go
+++ b/cobra/cmd/add.go
@@ -16,24 +16,20 @@ package cmd
 import (
 	"fmt"
 	"os"
-	"path/filepath"
 	"unicode"
 
 	"github.com/spf13/cobra"
 )
 
-func init() {
-	addCmd.Flags().StringVarP(&packageName, "package", "t", "", "target package name (e.g. github.com/spf13/hugo)")
-	addCmd.Flags().StringVarP(&parentName, "parent", "p", "rootCmd", "variable name of parent command for this command")
-}
-
-var packageName, parentName string
+var (
+	packageName string
+	parentName  string
 
-var addCmd = &cobra.Command{
-	Use:     "add [command name]",
-	Aliases: []string{"command"},
-	Short:   "Add a command to a Cobra Application",
-	Long: `Add (cobra add) will create a new command, with a license and
+	addCmd = &cobra.Command{
+		Use:     "add [command name]",
+		Aliases: []string{"command"},
+		Short:   "Add a command to a Cobra Application",
+		Long: `Add (cobra add) will create a new command, with a license and
 the appropriate structure for a Cobra-based CLI application,
 and register it to its parent (default rootCmd).
 
@@ -42,28 +38,41 @@ with an initial uppercase letter.
 
 Example: cobra add server -> resulting in a new cmd/server.go`,
 
-	Run: func(cmd *cobra.Command, args []string) {
-		if len(args) < 1 {
-			er("add needs a name for the command")
-		}
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) < 1 {
+				er("add needs a name for the command")
+			}
 
-		var project *Project
-		if packageName != "" {
-			project = NewProject(packageName)
-		} else {
 			wd, err := os.Getwd()
 			if err != nil {
 				er(err)
 			}
-			project = NewProjectFromPath(wd)
-		}
 
-		cmdName := validateCmdName(args[0])
-		cmdPath := filepath.Join(project.CmdPath(), cmdName+".go")
-		createCmdFile(project.License(), cmdPath, cmdName)
+			commandName := validateCmdName(args[0])
+			command := &Command{
+				CmdName:   commandName,
+				CmdParent: parentName,
+				Project: &Project{
+					AbsolutePath: wd,
+					Legal:        getLicense(),
+					Copyright:    copyrightLine(),
+				},
+			}
 
-		fmt.Fprintln(cmd.OutOrStdout(), cmdName, "created at", cmdPath)
-	},
+			err = command.Create()
+			if err != nil {
+				er(err)
+			}
+
+			fmt.Printf("%s created at %s", command.CmdName, command.AbsolutePath)
+		},
+	}
+)
+
+func init() {
+	addCmd.Flags().StringVarP(&packageName, "package", "t", "", "target package name (e.g. github.com/spf13/hugo)")
+	addCmd.Flags().StringVarP(&parentName, "parent", "p", "rootCmd", "variable name of parent command for this command")
+	addCmd.Flags().MarkDeprecated("package", "this operation has been removed.")
 }
 
 // validateCmdName returns source without any dashes and underscore.
@@ -118,62 +127,3 @@ func validateCmdName(source string) string {
 	}
 	return output
 }
-
-func createCmdFile(license License, path, cmdName string) {
-	template := `{{comment .copyright}}
-{{if .license}}{{comment .license}}{{end}}
-
-package {{.cmdPackage}}
-
-import (
-	"fmt"
-
-	"github.com/spf13/cobra"
-)
-
-// {{.cmdName}}Cmd represents the {{.cmdName}} command
-var {{.cmdName}}Cmd = &cobra.Command{
-	Use:   "{{.cmdName}}",
-	Short: "A brief description of your command",
-	Long: ` + "`" + `A longer description that spans multiple lines and likely contains examples
-and usage of using your command. For example:
-
-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.` + "`" + `,
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("{{.cmdName}} called")
-	},
-}
-
-func init() {
-	{{.parentName}}.AddCommand({{.cmdName}}Cmd)
-
-	// Here you will define your flags and configuration settings.
-
-	// Cobra supports Persistent Flags which will work for this command
-	// and all subcommands, e.g.:
-	// {{.cmdName}}Cmd.PersistentFlags().String("foo", "", "A help for foo")
-
-	// Cobra supports local flags which will only run when this command
-	// is called directly, e.g.:
-	// {{.cmdName}}Cmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
-}
-`
-
-	data := make(map[string]interface{})
-	data["copyright"] = copyrightLine()
-	data["license"] = license.Header
-	data["cmdPackage"] = filepath.Base(filepath.Dir(path)) // last dir of path
-	data["parentName"] = parentName
-	data["cmdName"] = cmdName
-
-	cmdScript, err := executeTemplate(template, data)
-	if err != nil {
-		er(err)
-	}
-	err = writeStringToFile(path, cmdScript)
-	if err != nil {
-		er(err)
-	}
-}
diff --git a/cobra/cmd/init.go b/cobra/cmd/init.go
index d65e6c8..63397d1 100644
--- a/cobra/cmd/init.go
+++ b/cobra/cmd/init.go
@@ -15,19 +15,20 @@ package cmd
 
 import (
 	"fmt"
-	"os"
-	"path"
-	"path/filepath"
-
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
+	"os"
+	"path"
 )
 
-var initCmd = &cobra.Command{
-	Use:     "init [name]",
-	Aliases: []string{"initialize", "initialise", "create"},
-	Short:   "Initialize a Cobra Application",
-	Long: `Initialize (cobra init) will create a new application, with a license
+var (
+	pkgName string
+
+	initCmd = &cobra.Command{
+		Use:     "init [name]",
+		Aliases: []string{"initialize", "initialise", "create"},
+		Short:   "Initialize a Cobra Application",
+		Long: `Initialize (cobra init) will create a new application, with a license
 and the appropriate structure for a Cobra-based CLI application.
 
   * If a name is provided, it will be created in the current directory;
@@ -39,196 +40,38 @@ and the appropriate structure for a Cobra-based CLI application.
 
 Init will not use an existing directory with contents.`,
 
-	Run: func(cmd *cobra.Command, args []string) {
-		wd, err := os.Getwd()
-		if err != nil {
-			er(err)
-		}
+		Run: func(cmd *cobra.Command, args []string) {
 
-		var project *Project
-		if len(args) == 0 {
-			project = NewProjectFromPath(wd)
-		} else if len(args) == 1 {
-			arg := args[0]
-			if arg[0] == '.' {
-				arg = filepath.Join(wd, arg)
+			wd, err := os.Getwd()
+			if err != nil {
+				er(err)
 			}
-			if filepath.IsAbs(arg) {
-				project = NewProjectFromPath(arg)
-			} else {
-				project = NewProject(arg)
-			}
-		} else {
-			er("please provide only one argument")
-		}
-
-		initializeProject(project)
-
-		fmt.Fprintln(cmd.OutOrStdout(), `Your Cobra application is ready at
-`+project.AbsPath()+`
-
-Give it a try by going there and running `+"`go run main.go`."+`
-Add commands to it by running `+"`cobra add [cmdname]`.")
-	},
-}
-
-func initializeProject(project *Project) {
-	if !exists(project.AbsPath()) { // If path doesn't yet exist, create it
-		err := os.MkdirAll(project.AbsPath(), os.ModePerm)
-		if err != nil {
-			er(err)
-		}
-	} else if !isEmpty(project.AbsPath()) { // If path exists and is not empty don't use it
-		er("Cobra will not create a new project in a non empty directory: " + project.AbsPath())
-	}
-
-	// We have a directory and it's empty. Time to initialize it.
-	createLicenseFile(project.License(), project.AbsPath())
-	createMainFile(project)
-	createRootCmdFile(project)
-}
 
-func createLicenseFile(license License, path string) {
-	data := make(map[string]interface{})
-	data["copyright"] = copyrightLine()
-
-	// Generate license template from text and data.
-	text, err := executeTemplate(license.Text, data)
-	if err != nil {
-		er(err)
-	}
-
-	// Write license text to LICENSE file.
-	err = writeStringToFile(filepath.Join(path, "LICENSE"), text)
-	if err != nil {
-		er(err)
-	}
-}
-
-func createMainFile(project *Project) {
-	mainTemplate := `{{ comment .copyright }}
-{{if .license}}{{ comment .license }}{{end}}
-
-package main
-
-import "{{ .importpath }}"
-
-func main() {
-	cmd.Execute()
-}
-`
-	data := make(map[string]interface{})
-	data["copyright"] = copyrightLine()
-	data["license"] = project.License().Header
-	data["importpath"] = path.Join(project.Name(), filepath.Base(project.CmdPath()))
-
-	mainScript, err := executeTemplate(mainTemplate, data)
-	if err != nil {
-		er(err)
-	}
-
-	err = writeStringToFile(filepath.Join(project.AbsPath(), "main.go"), mainScript)
-	if err != nil {
-		er(err)
-	}
-}
-
-func createRootCmdFile(project *Project) {
-	template := `{{comment .copyright}}
-{{if .license}}{{comment .license}}{{end}}
-
-package cmd
-
-import (
-	"fmt"
-	"os"
-{{if .viper}}
-	homedir "github.com/mitchellh/go-homedir"{{end}}
-	"github.com/spf13/cobra"{{if .viper}}
-	"github.com/spf13/viper"{{end}}
-){{if .viper}}
-
-var cfgFile string{{end}}
-
-// rootCmd represents the base command when called without any subcommands
-var rootCmd = &cobra.Command{
-	Use:   "{{.appName}}",
-	Short: "A brief description of your application",
-	Long: ` + "`" + `A longer description that spans multiple lines and likely contains
-examples and usage of using your application. For example:
-
-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.` + "`" + `,
-	// Uncomment the following line if your bare application
-	// has an action associated with it:
-	//	Run: func(cmd *cobra.Command, args []string) { },
-}
-
-// Execute adds all child commands to the root command and sets flags appropriately.
-// This is called by main.main(). It only needs to happen once to the rootCmd.
-func Execute() {
-	if err := rootCmd.Execute(); err != nil {
-		fmt.Println(err)
-		os.Exit(1)
-	}
-}
-
-func init() { {{- if .viper}}
-	cobra.OnInitialize(initConfig)
-{{end}}
-	// Here you will define your flags and configuration settings.
-	// Cobra supports persistent flags, which, if defined here,
-	// will be global for your application.{{ if .viper }}
-	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.{{ .appName }}.yaml)"){{ else }}
-	// rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.{{ .appName }}.yaml)"){{ end }}
-
-	// Cobra also supports local flags, which will only run
-	// when this action is called directly.
-	rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
-}{{ if .viper }}
-
-// initConfig reads in config file and ENV variables if set.
-func initConfig() {
-	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 ".{{ .appName }}" (without extension).
-		viper.AddConfigPath(home)
-		viper.SetConfigName(".{{ .appName }}")
-	}
-
-	viper.AutomaticEnv() // read in environment variables that match
-
-	// If a config file is found, read it in.
-	if err := viper.ReadInConfig(); err == nil {
-		fmt.Println("Using config file:", viper.ConfigFileUsed())
-	}
-}{{ end }}
-`
+			if len(args) > 0 {
+				if args[0] != "." {
+					wd = fmt.Sprintf("%s/%s", wd, args[0])
+				}
+			}
 
-	data := make(map[string]interface{})
-	data["copyright"] = copyrightLine()
-	data["viper"] = viper.GetBool("useViper")
-	data["license"] = project.License().Header
-	data["appName"] = path.Base(project.Name())
+			project := &Project{
+				AbsolutePath: wd,
+				PkgName:      pkgName,
+				Legal:        getLicense(),
+				Copyright:    copyrightLine(),
+				Viper:        viper.GetBool("useViper"),
+				AppName:      path.Base(pkgName),
+			}
 
-	rootCmdScript, err := executeTemplate(template, data)
-	if err != nil {
-		er(err)
-	}
+			if err := project.Create(); err != nil {
+				er(err)
+			}
 
-	err = writeStringToFile(filepath.Join(project.CmdPath(), "root.go"), rootCmdScript)
-	if err != nil {
-		er(err)
+			fmt.Printf("Your Cobra applicaton is ready at\n%s\n", project.AbsolutePath)
+		},
 	}
+)
 
+func init() {
+	initCmd.Flags().StringVar(&pkgName, "pkg-name", "", "fully qualified pkg name")
+	initCmd.MarkFlagRequired("pkg-name")
 }
diff --git a/cobra/cmd/project.go b/cobra/cmd/project.go
index 7ddb825..dd2f7ea 100644
--- a/cobra/cmd/project.go
+++ b/cobra/cmd/project.go
@@ -1,200 +1,96 @@
 package cmd
 
 import (
+	"fmt"
+	"github.com/spf13/cobra/cobra/tpl"
 	"os"
-	"path/filepath"
-	"runtime"
-	"strings"
+	"text/template"
 )
 
 // Project contains name, license and paths to projects.
 type Project struct {
-	absPath string
-	cmdPath string
-	srcPath string
-	license License
-	name    string
+	// v2
+	PkgName      string
+	Copyright    string
+	AbsolutePath string
+	Legal        License
+	Viper        bool
+	AppName      string
 }
 
-// NewProject returns Project with specified project name.
-func NewProject(projectName string) *Project {
-	if projectName == "" {
-		er("can't create project with blank name")
-	}
-
-	p := new(Project)
-	p.name = projectName
-
-	// 1. Find already created protect.
-	p.absPath = findPackage(projectName)
-
-	// 2. If there are no created project with this path, and user is in GOPATH,
-	// then use GOPATH/src/projectName.
-	if p.absPath == "" {
-		wd, err := os.Getwd()
-		if err != nil {
-			er(err)
-		}
-		for _, srcPath := range srcPaths {
-			goPath := filepath.Dir(srcPath)
-			if filepathHasPrefix(wd, goPath) {
-				p.absPath = filepath.Join(srcPath, projectName)
-				break
-			}
-		}
-	}
-
-	// 3. If user is not in GOPATH, then use (first GOPATH)/src/projectName.
-	if p.absPath == "" {
-		p.absPath = filepath.Join(srcPaths[0], projectName)
-	}
-
-	return p
+type Command struct {
+	CmdName   string
+	CmdParent string
+	*Project
 }
 
-// findPackage returns full path to existing go package in GOPATHs.
-func findPackage(packageName string) string {
-	if packageName == "" {
-		return ""
-	}
+func (p *Project) Create() error {
 
-	for _, srcPath := range srcPaths {
-		packagePath := filepath.Join(srcPath, packageName)
-		if exists(packagePath) {
-			return packagePath
+	// check if AbsolutePath exists
+	if _, err := os.Stat(p.AbsolutePath); os.IsNotExist(err) {
+		// create directory
+		if err := os.Mkdir(p.AbsolutePath, 0754); err != nil {
+			return err
 		}
 	}
 
-	return ""
-}
-
-// NewProjectFromPath returns Project with specified absolute path to
-// package.
-func NewProjectFromPath(absPath string) *Project {
-	if absPath == "" {
-		er("can't create project: absPath can't be blank")
-	}
-	if !filepath.IsAbs(absPath) {
-		er("can't create project: absPath is not absolute")
-	}
-
-	// If absPath is symlink, use its destination.
-	fi, err := os.Lstat(absPath)
+	// create main.go
+	mainFile, err := os.Create(fmt.Sprintf("%s/main.go", p.AbsolutePath))
 	if err != nil {
-		er("can't read path info: " + err.Error())
-	}
-	if fi.Mode()&os.ModeSymlink != 0 {
-		path, err := os.Readlink(absPath)
-		if err != nil {
-			er("can't read the destination of symlink: " + err.Error())
-		}
-		absPath = path
+		return err
 	}
+	defer mainFile.Close()
 
-	p := new(Project)
-	p.absPath = strings.TrimSuffix(absPath, findCmdDir(absPath))
-	p.name = filepath.ToSlash(trimSrcPath(p.absPath, p.SrcPath()))
-	return p
-}
-
-// trimSrcPath trims at the beginning of absPath the srcPath.
-func trimSrcPath(absPath, srcPath string) string {
-	relPath, err := filepath.Rel(srcPath, absPath)
+	mainTemplate := template.Must(template.New("main").Parse(string(tpl.MainTemplate())))
+	err = mainTemplate.Execute(mainFile, p)
 	if err != nil {
-		er(err)
-	}
-	return relPath
-}
-
-// License returns the License object of project.
-func (p *Project) License() License {
-	if p.license.Text == "" && p.license.Name != "None" {
-		p.license = getLicense()
-	}
-	return p.license
-}
-
-// Name returns the name of project, e.g. "github.com/spf13/cobra"
-func (p Project) Name() string {
-	return p.name
-}
-
-// CmdPath returns absolute path to directory, where all commands are located.
-func (p *Project) CmdPath() string {
-	if p.absPath == "" {
-		return ""
-	}
-	if p.cmdPath == "" {
-		p.cmdPath = filepath.Join(p.absPath, findCmdDir(p.absPath))
-	}
-	return p.cmdPath
-}
-
-// findCmdDir checks if base of absPath is cmd dir and returns it or
-// looks for existing cmd dir in absPath.
-func findCmdDir(absPath string) string {
-	if !exists(absPath) || isEmpty(absPath) {
-		return "cmd"
+		return err
 	}
 
-	if isCmdDir(absPath) {
-		return filepath.Base(absPath)
+	// create cmd/root.go
+	if _, err = os.Stat(fmt.Sprintf("%s/cmd", p.AbsolutePath)); os.IsNotExist(err) {
+		os.Mkdir(fmt.Sprintf("%s/cmd", p.AbsolutePath), 0751)
 	}
-
-	files, _ := filepath.Glob(filepath.Join(absPath, "c*"))
-	for _, file := range files {
-		if isCmdDir(file) {
-			return filepath.Base(file)
-		}
+	rootFile, err := os.Create(fmt.Sprintf("%s/cmd/root.go", p.AbsolutePath))
+	if err != nil {
+		return err
 	}
+	defer rootFile.Close()
 
-	return "cmd"
-}
-
-// isCmdDir checks if base of name is one of cmdDir.
-func isCmdDir(name string) bool {
-	name = filepath.Base(name)
-	for _, cmdDir := range []string{"cmd", "cmds", "command", "commands"} {
-		if name == cmdDir {
-			return true
-		}
+	rootTemplate := template.Must(template.New("root").Parse(string(tpl.RootTemplate())))
+	err = rootTemplate.Execute(rootFile, p)
+	if err != nil {
+		return err
 	}
-	return false
-}
 
-// AbsPath returns absolute path of project.
-func (p Project) AbsPath() string {
-	return p.absPath
+	// create license
+	return p.createLicenseFile()
 }
 
-// SrcPath returns absolute path to $GOPATH/src where project is located.
-func (p *Project) SrcPath() string {
-	if p.srcPath != "" {
-		return p.srcPath
-	}
-	if p.absPath == "" {
-		p.srcPath = srcPaths[0]
-		return p.srcPath
+func (p *Project) createLicenseFile() error {
+	data := map[string]interface{}{
+		"copyright": copyrightLine(),
 	}
-
-	for _, srcPath := range srcPaths {
-		if filepathHasPrefix(p.absPath, srcPath) {
-			p.srcPath = srcPath
-			break
-		}
+	licenseFile, err := os.Create(fmt.Sprintf("%s/LICENSE", p.AbsolutePath))
+	if err != nil {
+		return err
 	}
 
-	return p.srcPath
+	licenseTemplate := template.Must(template.New("license").Parse(p.Legal.Text))
+	return licenseTemplate.Execute(licenseFile, data)
 }
 
-func filepathHasPrefix(path string, prefix string) bool {
-	if len(path) <= len(prefix) {
-		return false
-	}
-	if runtime.GOOS == "windows" {
-		// Paths in windows are case-insensitive.
-		return strings.EqualFold(path[0:len(prefix)], prefix)
+func (c *Command) Create() error {
+	cmdFile, err := os.Create(fmt.Sprintf("%s/cmd/%s.go", c.AbsolutePath, c.CmdName))
+	if err != nil {
+		return err
 	}
-	return path[0:len(prefix)] == prefix
+	defer cmdFile.Close()
 
+	commandTemplate := template.Must(template.New("sub").Parse(string(tpl.AddCommandTemplate())))
+	err = commandTemplate.Execute(cmdFile, c)
+	if err != nil {
+		return err
+	}
+	return nil
 }
diff --git a/cobra/cmd/root.go b/cobra/cmd/root.go
index 19568f9..624c717 100644
--- a/cobra/cmd/root.go
+++ b/cobra/cmd/root.go
@@ -23,7 +23,8 @@ import (
 
 var (
 	// Used for flags.
-	cfgFile, userLicense string
+	cfgFile     string
+	userLicense string
 
 	rootCmd = &cobra.Command{
 		Use:   "cobra",
diff --git a/cobra/tpl/main.go b/cobra/tpl/main.go
new file mode 100644
index 0000000..5e5a0fa
--- /dev/null
+++ b/cobra/tpl/main.go
@@ -0,0 +1,153 @@
+package tpl
+
+func MainTemplate() []byte {
+	return []byte(`/*
+{{ .Copyright }}
+{{ if .Legal.Header }}{{ .Legal.Header }}{{ end }}
+*/
+package main
+
+import "{{ .PkgName }}/cmd"
+
+func main() {
+  cmd.Execute()
+}
+`)
+}
+
+func RootTemplate() []byte {
+	return []byte(`/*
+{{ .Copyright }}
+{{ if .Legal.Header }}{{ .Legal.Header }}{{ end }}
+*/
+package cmd
+
+import (
+  "fmt"
+  "os"
+  "github.com/spf13/cobra"
+{{ if .Viper }}
+  homedir "github.com/mitchellh/go-homedir"
+  "github.com/spf13/viper"
+{{ end }}
+)
+
+{{ if .Viper }}
+var cfgFile string
+{{ end }}
+
+// rootCmd represents the base command when called without any subcommands
+var rootCmd = &cobra.Command{
+  Use:   "{{ .AppName }}",
+  Short: "A brief description of your application",
+  Long: ` + "`" + `A longer description that spans multiple lines and likely contains
+examples and usage of using your application. For example:
+
+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.` + "`" + `,
+  // Uncomment the following line if your bare application
+  // has an action associated with it:
+  //	Run: func(cmd *cobra.Command, args []string) { },
+}
+
+// Execute adds all child commands to the root command and sets flags appropriately.
+// This is called by main.main(). It only needs to happen once to the rootCmd.
+func Execute() {
+  if err := rootCmd.Execute(); err != nil {
+    fmt.Println(err)
+    os.Exit(1)
+  }
+}
+
+func init() {
+{{- if .Viper }}
+  cobra.OnInitialize(initConfig)
+{{ end }}
+  // Here you will define your flags and configuration settings.
+  // Cobra supports persistent flags, which, if defined here,
+  // will be global for your application.
+{{ if .Viper }}
+  rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.{{ .AppName }}.yaml)")
+{{ else }}
+  // rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.{{ .AppName }}.yaml)")
+{{ end }}
+
+  // Cobra also supports local flags, which will only run
+  // when this action is called directly.
+  rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
+}
+
+{{ if .Viper }}
+// initConfig reads in config file and ENV variables if set.
+func initConfig() {
+  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 ".{{ .AppName }}" (without extension).
+    viper.AddConfigPath(home)
+    viper.SetConfigName(".{{ .AppName }}")
+  }
+
+  viper.AutomaticEnv() // read in environment variables that match
+
+  // If a config file is found, read it in.
+  if err := viper.ReadInConfig(); err == nil {
+    fmt.Println("Using config file:", viper.ConfigFileUsed())
+  }
+}
+{{ end }}
+`)
+}
+
+func AddCommandTemplate() []byte {
+	return []byte(`/*
+{{ .Project.Copyright }}
+{{ if .Legal.Header }}{{ .Legal.Header }}{{ end }}
+*/
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+// {{ .CmdName }}Cmd represents the {{ .CmdName }} command
+var {{ .CmdName }}Cmd = &cobra.Command{
+	Use:   "{{ .CmdName }}",
+	Short: "A brief description of your command",
+	Long: ` + "`" + `A longer description that spans multiple lines and likely contains examples
+and usage of using your command. For example:
+
+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.` + "`" + `,
+	Run: func(cmd *cobra.Command, args []string) {
+		fmt.Println("{{ .CmdName }} called")
+	},
+}
+
+func init() {
+	{{ .CmdParent }}.AddCommand({{ .CmdName }}Cmd)
+
+	// Here you will define your flags and configuration settings.
+
+	// Cobra supports Persistent Flags which will work for this command
+	// and all subcommands, e.g.:
+	// {{ .CmdName }}Cmd.PersistentFlags().String("foo", "", "A help for foo")
+
+	// Cobra supports local flags which will only run when this command
+	// is called directly, e.g.:
+	// {{ .CmdName }}Cmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
+}
+`)
+}
diff --git a/powershell_completions.go b/powershell_completions.go
new file mode 100644
index 0000000..756c61b
--- /dev/null
+++ b/powershell_completions.go
@@ -0,0 +1,100 @@
+// PowerShell completions are based on the amazing work from clap:
+// https://github.com/clap-rs/clap/blob/3294d18efe5f264d12c9035f404c7d189d4824e1/src/completions/powershell.rs
+//
+// The generated scripts require PowerShell v5.0+ (which comes Windows 10, but
+// can be downloaded separately for windows 7 or 8.1).
+
+package cobra
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/spf13/pflag"
+)
+
+var powerShellCompletionTemplate = `using namespace System.Management.Automation
+using namespace System.Management.Automation.Language
+Register-ArgumentCompleter -Native -CommandName '%s' -ScriptBlock {
+    param($wordToComplete, $commandAst, $cursorPosition)
+    $commandElements = $commandAst.CommandElements
+    $command = @(
+        '%s'
+        for ($i = 1; $i -lt $commandElements.Count; $i++) {
+            $element = $commandElements[$i]
+            if ($element -isnot [StringConstantExpressionAst] -or
+                $element.StringConstantType -ne [StringConstantType]::BareWord -or
+                $element.Value.StartsWith('-')) {
+                break
+            }
+            $element.Value
+        }
+    ) -join ';'
+    $completions = @(switch ($command) {%s
+    })
+    $completions.Where{ $_.CompletionText -like "$wordToComplete*" } |
+        Sort-Object -Property ListItemText
+}`
+
+func generatePowerShellSubcommandCases(out io.Writer, cmd *Command, previousCommandName string) {
+	var cmdName string
+	if previousCommandName == "" {
+		cmdName = cmd.Name()
+	} else {
+		cmdName = fmt.Sprintf("%s;%s", previousCommandName, cmd.Name())
+	}
+
+	fmt.Fprintf(out, "\n        '%s' {", cmdName)
+
+	cmd.Flags().VisitAll(func(flag *pflag.Flag) {
+		if nonCompletableFlag(flag) {
+			return
+		}
+		usage := escapeStringForPowerShell(flag.Usage)
+		if len(flag.Shorthand) > 0 {
+			fmt.Fprintf(out, "\n            [CompletionResult]::new('-%s', '%s', [CompletionResultType]::ParameterName, '%s')", flag.Shorthand, flag.Shorthand, usage)
+		}
+		fmt.Fprintf(out, "\n            [CompletionResult]::new('--%s', '%s', [CompletionResultType]::ParameterName, '%s')", flag.Name, flag.Name, usage)
+	})
+
+	for _, subCmd := range cmd.Commands() {
+		usage := escapeStringForPowerShell(subCmd.Short)
+		fmt.Fprintf(out, "\n            [CompletionResult]::new('%s', '%s', [CompletionResultType]::ParameterValue, '%s')", subCmd.Name(), subCmd.Name(), usage)
+	}
+
+	fmt.Fprint(out, "\n            break\n        }")
+
+	for _, subCmd := range cmd.Commands() {
+		generatePowerShellSubcommandCases(out, subCmd, cmdName)
+	}
+}
+
+func escapeStringForPowerShell(s string) string {
+	return strings.Replace(s, "'", "''", -1)
+}
+
+// GenPowerShellCompletion generates PowerShell completion file and writes to the passed writer.
+func (c *Command) GenPowerShellCompletion(w io.Writer) error {
+	buf := new(bytes.Buffer)
+
+	var subCommandCases bytes.Buffer
+	generatePowerShellSubcommandCases(&subCommandCases, c, "")
+	fmt.Fprintf(buf, powerShellCompletionTemplate, c.Name(), c.Name(), subCommandCases.String())
+
+	_, err := buf.WriteTo(w)
+	return err
+}
+
+// GenPowerShellCompletionFile generates PowerShell completion file.
+func (c *Command) GenPowerShellCompletionFile(filename string) error {
+	outFile, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	return c.GenPowerShellCompletion(outFile)
+}
diff --git a/powershell_completions.md b/powershell_completions.md
new file mode 100644
index 0000000..afed802
--- /dev/null
+++ b/powershell_completions.md
@@ -0,0 +1,14 @@
+# Generating PowerShell Completions For Your Own cobra.Command
+
+Cobra can generate PowerShell completion scripts. Users need PowerShell version 5.0 or above, which comes with Windows 10 and can be downloaded separately for Windows 7 or 8.1. They can then write the completions to a file and source this file from their PowerShell profile, which is referenced by the `$Profile` environment variable. See `Get-Help about_Profiles` for more info about PowerShell profiles.
+
+# What's supported
+
+- Completion for subcommands using their `.Short` description
+- Completion for non-hidden flags using their `.Name` and `.Shorthand`
+
+# What's not yet supported
+
+- Command aliases
+- Required, filename or custom flags (they will work like normal flags)
+- Custom completion scripts
diff --git a/shell_completions.go b/shell_completions.go
new file mode 100644
index 0000000..ba0af9c
--- /dev/null
+++ b/shell_completions.go
@@ -0,0 +1,85 @@
+package cobra
+
+import (
+	"github.com/spf13/pflag"
+)
+
+// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
+// and causes your command to report an error if invoked without the flag.
+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,
+// and causes your command to report an error if invoked without the flag.
+func (c *Command) MarkPersistentFlagRequired(name string) error {
+	return MarkFlagRequired(c.PersistentFlags(), name)
+}
+
+// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
+// and causes your command to report an error if invoked without the flag.
+func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
+	return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"})
+}
+
+// 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 (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 (c *Command) MarkFlagCustom(name string, f string) error {
+	return MarkFlagCustom(c.Flags(), name, f)
+}
+
+// MarkPersistentFlagFilename instructs the various shell completion
+// implementations to limit completions for this persistent flag to the
+// specified extensions (patterns).
+//
+// Shell Completion compatibility matrix: bash, zsh
+func (c *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.PersistentFlags(), name, extensions...)
+}
+
+// MarkFlagFilename instructs the various shell completion implementations to
+// limit completions for this flag to the specified extensions (patterns).
+//
+// Shell Completion compatibility matrix: bash, zsh
+func MarkFlagFilename(flags *pflag.FlagSet, name string, extensions ...string) error {
+	return flags.SetAnnotation(name, BashCompFilenameExt, extensions)
+}
+
+// MarkFlagCustom instructs the various shell completion implementations to
+// limit completions for this flag to the specified extensions (patterns).
+//
+// Shell Completion compatibility matrix: bash, zsh
+func MarkFlagCustom(flags *pflag.FlagSet, name string, f string) error {
+	return flags.SetAnnotation(name, BashCompCustom, []string{f})
+}
+
+// MarkFlagDirname instructs the various shell completion implementations to
+// complete only directories with this named flag.
+//
+// Shell Completion compatibility matrix: zsh
+func (c *Command) MarkFlagDirname(name string) error {
+	return MarkFlagDirname(c.Flags(), name)
+}
+
+// MarkPersistentFlagDirname instructs the various shell completion
+// implementations to complete only directories with this persistent named flag.
+//
+// Shell Completion compatibility matrix: zsh
+func (c *Command) MarkPersistentFlagDirname(name string) error {
+	return MarkFlagDirname(c.PersistentFlags(), name)
+}
+
+// MarkFlagDirname instructs the various shell completion implementations to
+// complete only directories with this specified flag.
+//
+// Shell Completion compatibility matrix: zsh
+func MarkFlagDirname(flags *pflag.FlagSet, name string) error {
+	zshPattern := "-(/)"
+	return flags.SetAnnotation(name, zshCompDirname, []string{zshPattern})
+}
diff --git a/zsh_completions.go b/zsh_completions.go
index 889c22e..1275548 100644
--- a/zsh_completions.go
+++ b/zsh_completions.go
@@ -1,13 +1,102 @@
 package cobra
 
 import (
-	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
 	"os"
+	"sort"
 	"strings"
+	"text/template"
+
+	"github.com/spf13/pflag"
+)
+
+const (
+	zshCompArgumentAnnotation   = "cobra_annotations_zsh_completion_argument_annotation"
+	zshCompArgumentFilenameComp = "cobra_annotations_zsh_completion_argument_file_completion"
+	zshCompArgumentWordComp     = "cobra_annotations_zsh_completion_argument_word_completion"
+	zshCompDirname              = "cobra_annotations_zsh_dirname"
+)
+
+var (
+	zshCompFuncMap = template.FuncMap{
+		"genZshFuncName":              zshCompGenFuncName,
+		"extractFlags":                zshCompExtractFlag,
+		"genFlagEntryForZshArguments": zshCompGenFlagEntryForArguments,
+		"extractArgsCompletions":      zshCompExtractArgumentCompletionHintsForRendering,
+	}
+	zshCompletionText = `
+{{/* should accept Command (that contains subcommands) as parameter */}}
+{{define "argumentsC" -}}
+{{ $cmdPath := genZshFuncName .}}
+function {{$cmdPath}} {
+  local -a commands
+
+  _arguments -C \{{- range extractFlags .}}
+    {{genFlagEntryForZshArguments .}} \{{- end}}
+    "1: :->cmnds" \
+    "*::arg:->args"
+
+  case $state in
+  cmnds)
+    commands=({{range .Commands}}{{if not .Hidden}}
+      "{{.Name}}:{{.Short}}"{{end}}{{end}}
+    )
+    _describe "command" commands
+    ;;
+  esac
+
+  case "$words[1]" in {{- range .Commands}}{{if not .Hidden}}
+  {{.Name}})
+    {{$cmdPath}}_{{.Name}}
+    ;;{{end}}{{end}}
+  esac
+}
+{{range .Commands}}{{if not .Hidden}}
+{{template "selectCmdTemplate" .}}
+{{- end}}{{end}}
+{{- end}}
+
+{{/* should accept Command without subcommands as parameter */}}
+{{define "arguments" -}}
+function {{genZshFuncName .}} {
+{{"  _arguments"}}{{range extractFlags .}} \
+    {{genFlagEntryForZshArguments . -}}
+{{end}}{{range extractArgsCompletions .}} \
+    {{.}}{{end}}
+}
+{{end}}
+
+{{/* dispatcher for commands with or without subcommands */}}
+{{define "selectCmdTemplate" -}}
+{{if .Hidden}}{{/* ignore hidden*/}}{{else -}}
+{{if .Commands}}{{template "argumentsC" .}}{{else}}{{template "arguments" .}}{{end}}
+{{- end}}
+{{- end}}
+
+{{/* template entry point */}}
+{{define "Main" -}}
+#compdef _{{.Name}} {{.Name}}
+
+{{template "selectCmdTemplate" .}}
+{{end}}
+`
 )
 
+// zshCompArgsAnnotation is used to encode/decode zsh completion for
+// arguments to/from Command.Annotations.
+type zshCompArgsAnnotation map[int]zshCompArgHint
+
+type zshCompArgHint struct {
+	// Indicates the type of the completion to use. One of:
+	// zshCompArgumentFilenameComp or zshCompArgumentWordComp
+	Tipe string `json:"type"`
+
+	// A value for the type above (globs for file completion or words)
+	Options []string `json:"options"`
+}
+
 // GenZshCompletionFile generates zsh completion file.
 func (c *Command) GenZshCompletionFile(filename string) error {
 	outFile, err := os.Create(filename)
@@ -19,108 +108,229 @@ func (c *Command) GenZshCompletionFile(filename string) error {
 	return c.GenZshCompletion(outFile)
 }
 
-// GenZshCompletion generates a zsh completion file and writes to the passed writer.
+// GenZshCompletion generates a zsh completion file and writes to the passed
+// writer. The completion always run on the root command regardless of the
+// command it was called from.
 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)
+	tmpl, err := template.New("Main").Funcs(zshCompFuncMap).Parse(zshCompletionText)
+	if err != nil {
+		return fmt.Errorf("error creating zsh completion template: %v", err)
+	}
+	return tmpl.Execute(w, c.Root())
+}
 
-	_, err := buf.WriteTo(w)
-	return err
+// MarkZshCompPositionalArgumentFile marks the specified argument (first
+// argument is 1) as completed by file selection. patterns (e.g. "*.txt") are
+// optional - if not provided the completion will search for all files.
+func (c *Command) MarkZshCompPositionalArgumentFile(argPosition int, patterns ...string) error {
+	if argPosition < 1 {
+		return fmt.Errorf("Invalid argument position (%d)", argPosition)
+	}
+	annotation, err := c.zshCompGetArgsAnnotations()
+	if err != nil {
+		return err
+	}
+	if c.zshcompArgsAnnotationnIsDuplicatePosition(annotation, argPosition) {
+		return fmt.Errorf("Duplicate annotation for positional argument at index %d", argPosition)
+	}
+	annotation[argPosition] = zshCompArgHint{
+		Tipe:    zshCompArgumentFilenameComp,
+		Options: patterns,
+	}
+	return c.zshCompSetArgsAnnotations(annotation)
 }
 
-func writeHeader(w io.Writer, cmd *Command) {
-	fmt.Fprintf(w, "#compdef %s\n\n", cmd.Name())
+// MarkZshCompPositionalArgumentWords marks the specified positional argument
+// (first argument is 1) as completed by the provided words. At east one word
+// must be provided, spaces within words will be offered completion with
+// "word\ word".
+func (c *Command) MarkZshCompPositionalArgumentWords(argPosition int, words ...string) error {
+	if argPosition < 1 {
+		return fmt.Errorf("Invalid argument position (%d)", argPosition)
+	}
+	if len(words) == 0 {
+		return fmt.Errorf("Trying to set empty word list for positional argument %d", argPosition)
+	}
+	annotation, err := c.zshCompGetArgsAnnotations()
+	if err != nil {
+		return err
+	}
+	if c.zshcompArgsAnnotationnIsDuplicatePosition(annotation, argPosition) {
+		return fmt.Errorf("Duplicate annotation for positional argument at index %d", argPosition)
+	}
+	annotation[argPosition] = zshCompArgHint{
+		Tipe:    zshCompArgumentWordComp,
+		Options: words,
+	}
+	return c.zshCompSetArgsAnnotations(annotation)
 }
 
-func maxDepth(c *Command) int {
-	if len(c.Commands()) == 0 {
-		return 0
+func zshCompExtractArgumentCompletionHintsForRendering(c *Command) ([]string, error) {
+	var result []string
+	annotation, err := c.zshCompGetArgsAnnotations()
+	if err != nil {
+		return nil, err
 	}
-	maxDepthSub := 0
-	for _, s := range c.Commands() {
-		subDepth := maxDepth(s)
-		if subDepth > maxDepthSub {
-			maxDepthSub = subDepth
+	for k, v := range annotation {
+		s, err := zshCompRenderZshCompArgHint(k, v)
+		if err != nil {
+			return nil, err
 		}
+		result = append(result, s)
 	}
-	return 1 + maxDepthSub
+	if len(c.ValidArgs) > 0 {
+		if _, positionOneExists := annotation[1]; !positionOneExists {
+			s, err := zshCompRenderZshCompArgHint(1, zshCompArgHint{
+				Tipe:    zshCompArgumentWordComp,
+				Options: c.ValidArgs,
+			})
+			if err != nil {
+				return nil, err
+			}
+			result = append(result, s)
+		}
+	}
+	sort.Strings(result)
+	return result, nil
 }
 
-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)
+func zshCompRenderZshCompArgHint(i int, z zshCompArgHint) (string, error) {
+	switch t := z.Tipe; t {
+	case zshCompArgumentFilenameComp:
+		var globs []string
+		for _, g := range z.Options {
+			globs = append(globs, fmt.Sprintf(`-g "%s"`, g))
+		}
+		return fmt.Sprintf(`'%d: :_files %s'`, i, strings.Join(globs, " ")), nil
+	case zshCompArgumentWordComp:
+		var words []string
+		for _, w := range z.Options {
+			words = append(words, fmt.Sprintf("%q", w))
+		}
+		return fmt.Sprintf(`'%d: :(%s)'`, i, strings.Join(words, " ")), nil
+	default:
+		return "", fmt.Errorf("Invalid zsh argument completion annotation: %s", t)
 	}
-	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")
+func (c *Command) zshcompArgsAnnotationnIsDuplicatePosition(annotation zshCompArgsAnnotation, position int) bool {
+	_, dup := annotation[position]
+	return dup
+}
 
-	for i := 1; i <= maxDepth; i++ {
-		fmt.Fprintf(w, "  level%d)\n", i)
-		writeLevel(w, root, i)
-		fmt.Fprintln(w, "  ;;")
+func (c *Command) zshCompGetArgsAnnotations() (zshCompArgsAnnotation, error) {
+	annotation := make(zshCompArgsAnnotation)
+	annotationString, ok := c.Annotations[zshCompArgumentAnnotation]
+	if !ok {
+		return annotation, nil
+	}
+	err := json.Unmarshal([]byte(annotationString), &annotation)
+	if err != nil {
+		return annotation, fmt.Errorf("Error unmarshaling zsh argument annotation: %v", err)
 	}
-	fmt.Fprintln(w, "  *)")
-	fmt.Fprintln(w, "    _arguments '*: :_files'")
-	fmt.Fprintln(w, "  ;;")
+	return annotation, nil
 }
 
-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)
+func (c *Command) zshCompSetArgsAnnotations(annotation zshCompArgsAnnotation) error {
+	jsn, err := json.Marshal(annotation)
+	if err != nil {
+		return fmt.Errorf("Error marshaling zsh argument annotation: %v", err)
+	}
+	if c.Annotations == nil {
+		c.Annotations = make(map[string]string)
+	}
+	c.Annotations[zshCompArgumentAnnotation] = string(jsn)
+	return nil
+}
 
-	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, "      ;;")
+func zshCompGenFuncName(c *Command) string {
+	if c.HasParent() {
+		return zshCompGenFuncName(c.Parent()) + "_" + c.Name()
 	}
-	fmt.Fprintln(w, "      *)")
-	fmt.Fprintln(w, "        _arguments '*: :_files'")
-	fmt.Fprintln(w, "      ;;")
+	return "_" + c.Name()
+}
 
+func zshCompExtractFlag(c *Command) []*pflag.Flag {
+	var flags []*pflag.Flag
+	c.LocalFlags().VisitAll(func(f *pflag.Flag) {
+		if !f.Hidden {
+			flags = append(flags, f)
+		}
+	})
+	c.InheritedFlags().VisitAll(func(f *pflag.Flag) {
+		if !f.Hidden {
+			flags = append(flags, f)
+		}
+	})
+	return flags
 }
 
-func filterByLevel(c *Command, l int) []*Command {
-	cs := make([]*Command, 0)
-	if l == 0 {
-		cs = append(cs, c)
-		return cs
+// zshCompGenFlagEntryForArguments returns an entry that matches _arguments
+// zsh-completion parameters. It's too complicated to generate in a template.
+func zshCompGenFlagEntryForArguments(f *pflag.Flag) string {
+	if f.Name == "" || f.Shorthand == "" {
+		return zshCompGenFlagEntryForSingleOptionFlag(f)
 	}
-	for _, s := range c.Commands() {
-		cs = append(cs, filterByLevel(s, l-1)...)
+	return zshCompGenFlagEntryForMultiOptionFlag(f)
+}
+
+func zshCompGenFlagEntryForSingleOptionFlag(f *pflag.Flag) string {
+	var option, multiMark, extras string
+
+	if zshCompFlagCouldBeSpecifiedMoreThenOnce(f) {
+		multiMark = "*"
 	}
-	return cs
+
+	option = "--" + f.Name
+	if option == "--" {
+		option = "-" + f.Shorthand
+	}
+	extras = zshCompGenFlagEntryExtras(f)
+
+	return fmt.Sprintf(`'%s%s[%s]%s'`, multiMark, option, zshCompQuoteFlagDescription(f.Usage), extras)
 }
 
-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)
+func zshCompGenFlagEntryForMultiOptionFlag(f *pflag.Flag) string {
+	var options, parenMultiMark, curlyMultiMark, extras string
+
+	if zshCompFlagCouldBeSpecifiedMoreThenOnce(f) {
+		parenMultiMark = "*"
+		curlyMultiMark = "\\*"
 	}
-	return m
+
+	options = fmt.Sprintf(`'(%s-%s %s--%s)'{%s-%s,%s--%s}`,
+		parenMultiMark, f.Shorthand, parenMultiMark, f.Name, curlyMultiMark, f.Shorthand, curlyMultiMark, f.Name)
+	extras = zshCompGenFlagEntryExtras(f)
+
+	return fmt.Sprintf(`%s'[%s]%s'`, options, zshCompQuoteFlagDescription(f.Usage), extras)
 }
 
-func names(commands []*Command) []string {
-	ns := make([]string, len(commands))
-	for i, c := range commands {
-		ns[i] = c.Name()
+func zshCompGenFlagEntryExtras(f *pflag.Flag) string {
+	if f.NoOptDefVal != "" {
+		return ""
 	}
-	return ns
+
+	extras := ":" // allow options for flag (even without assistance)
+	for key, values := range f.Annotations {
+		switch key {
+		case zshCompDirname:
+			extras = fmt.Sprintf(":filename:_files -g %q", values[0])
+		case BashCompFilenameExt:
+			extras = ":filename:_files"
+			for _, pattern := range values {
+				extras = extras + fmt.Sprintf(` -g "%s"`, pattern)
+			}
+		}
+	}
+
+	return extras
+}
+
+func zshCompFlagCouldBeSpecifiedMoreThenOnce(f *pflag.Flag) bool {
+	return strings.Contains(f.Value.Type(), "Slice") ||
+		strings.Contains(f.Value.Type(), "Array")
+}
+
+func zshCompQuoteFlagDescription(s string) string {
+	return strings.Replace(s, "'", `'\''`, -1)
 }
diff --git a/zsh_completions.md b/zsh_completions.md
new file mode 100644
index 0000000..df9c2ea
--- /dev/null
+++ b/zsh_completions.md
@@ -0,0 +1,39 @@
+## Generating Zsh Completion for your cobra.Command
+
+Cobra supports native Zsh completion generated from the root `cobra.Command`.
+The generated completion script should be put somewhere in your `$fpath` named
+`_<YOUR COMMAND>`.
+
+### What's Supported
+
+* Completion for all non-hidden subcommands using their `.Short` description.
+* Completion for all non-hidden flags using the following rules:
+  * Filename completion works by marking the flag with `cmd.MarkFlagFilename...`
+    family of commands.
+  * The requirement for argument to the flag is decided by the `.NoOptDefVal`
+    flag value - if it's empty then completion will expect an argument.
+  * Flags of one of the various `*Array` and `*Slice` types supports multiple
+    specifications (with or without argument depending on the specific type).
+* Completion of positional arguments using the following rules:
+  * Argument position for all options below starts at `1`. If argument position
+    `0` is requested it will raise an error.
+  * Use `command.MarkZshCompPositionalArgumentFile` to complete filenames. Glob
+    patterns (e.g. `"*.log"`) are optional - if not specified it will offer to
+    complete all file types.
+  * Use `command.MarkZshCompPositionalArgumentWords` to offer specific words for
+    completion. At least one word is required.
+  * It's possible to specify completion for some arguments and leave some
+    unspecified (e.g. offer words for second argument but nothing for first
+    argument). This will cause no completion for first argument but words
+    completion for second argument.
+  * If no argument completion was specified for 1st argument (but optionally was
+    specified for 2nd) and the command has `ValidArgs` it will be used as
+    completion options for 1st argument.
+  * Argument completions only offered for commands with no subcommands.
+
+### What's not yet Supported
+
+* Custom completion scripts are not supported yet (We should probably create zsh
+  specific one, doesn't make sense to re-use the bash one as the functions will
+  be different).
+* Whatever other feature you're looking for and doesn't exist :)


Test patch:
diff --git a/cobra/cmd/add_test.go b/cobra/cmd/add_test.go
index b920e2b..0de1d22 100644
--- a/cobra/cmd/add_test.go
+++ b/cobra/cmd/add_test.go
@@ -1,85 +1,45 @@
 package cmd
 
 import (
-	"errors"
-	"io/ioutil"
+	"fmt"
 	"os"
-	"path/filepath"
 	"testing"
-
-	"github.com/spf13/viper"
 )
 
-// TestGoldenAddCmd initializes the project "github.com/spf13/testproject"
-// in GOPATH, adds "test" command
-// and compares the content of all files in cmd directory of testproject
-// with appropriate golden files.
-// Use -update to update existing golden files.
 func TestGoldenAddCmd(t *testing.T) {
-	projectName := "github.com/spf13/testproject"
-	project := NewProject(projectName)
-	defer os.RemoveAll(project.AbsPath())
-
-	viper.Set("author", "NAME HERE <EMAIL ADDRESS>")
-	viper.Set("license", "apache")
-	viper.Set("year", 2017)
-	defer viper.Set("author", nil)
-	defer viper.Set("license", nil)
-	defer viper.Set("year", nil)
-
-	// Initialize the project first.
-	initializeProject(project)
 
-	// Then add the "test" command.
-	cmdName := "test"
-	cmdPath := filepath.Join(project.CmdPath(), cmdName+".go")
-	createCmdFile(project.License(), cmdPath, cmdName)
+	wd, _ := os.Getwd()
+	command := &Command{
+		CmdName:   "test",
+		CmdParent: parentName,
+		Project: &Project{
+			AbsolutePath: fmt.Sprintf("%s/testproject", wd),
+			Legal:        getLicense(),
+			Copyright:    copyrightLine(),
 
-	expectedFiles := []string{".", "root.go", "test.go"}
-	gotFiles := []string{}
-
-	// Check project file hierarchy and compare the content of every single file
-	// with appropriate golden file.
-	err := filepath.Walk(project.CmdPath(), func(path string, info os.FileInfo, err error) error {
-		if err != nil {
-			return err
-		}
+			// required to init
+			AppName: "testproject",
+			PkgName: "github.com/spf13/testproject",
+			Viper:   true,
+		},
+	}
 
-		// Make path relative to project.CmdPath().
-		// E.g. path = "/home/user/go/src/github.com/spf13/testproject/cmd/root.go"
-		// then it returns just "root.go".
-		relPath, err := filepath.Rel(project.CmdPath(), path)
-		if err != nil {
-			return err
+	// init project first
+	command.Project.Create()
+	defer func() {
+		if _, err := os.Stat(command.AbsolutePath); err == nil {
+			os.RemoveAll(command.AbsolutePath)
 		}
-		relPath = filepath.ToSlash(relPath)
-		gotFiles = append(gotFiles, relPath)
-		goldenPath := filepath.Join("testdata", filepath.Base(path)+".golden")
+	}()
 
-		switch relPath {
-		// Known directories.
-		case ".":
-			return nil
-		// Known files.
-		case "root.go", "test.go":
-			if *update {
-				got, err := ioutil.ReadFile(path)
-				if err != nil {
-					return err
-				}
-				ioutil.WriteFile(goldenPath, got, 0644)
-			}
-			return compareFiles(path, goldenPath)
-		}
-		// Unknown file.
-		return errors.New("unknown file: " + path)
-	})
-	if err != nil {
+	if err := command.Create(); err != nil {
 		t.Fatal(err)
 	}
 
-	// Check if some files lack.
-	if err := checkLackFiles(expectedFiles, gotFiles); err != nil {
+	generatedFile := fmt.Sprintf("%s/cmd/%s.go", command.AbsolutePath, command.CmdName)
+	goldenFile := fmt.Sprintf("testdata/%s.go.golden", command.CmdName)
+	err := compareFiles(generatedFile, goldenFile)
+	if err != nil {
 		t.Fatal(err)
 	}
 }
diff --git a/cobra/cmd/init_test.go b/cobra/cmd/init_test.go
index 40eb403..9540b2d 100644
--- a/cobra/cmd/init_test.go
+++ b/cobra/cmd/init_test.go
@@ -1,83 +1,42 @@
 package cmd
 
 import (
-	"errors"
-	"io/ioutil"
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
-
-	"github.com/spf13/viper"
 )
 
-// TestGoldenInitCmd initializes the project "github.com/spf13/testproject"
-// in GOPATH and compares the content of files in initialized project with
-// appropriate golden files ("testdata/*.golden").
-// Use -update to update existing golden files.
 func TestGoldenInitCmd(t *testing.T) {
-	projectName := "github.com/spf13/testproject"
-	project := NewProject(projectName)
-	defer os.RemoveAll(project.AbsPath())
-
-	viper.Set("author", "NAME HERE <EMAIL ADDRESS>")
-	viper.Set("license", "apache")
-	viper.Set("year", 2017)
-	defer viper.Set("author", nil)
-	defer viper.Set("license", nil)
-	defer viper.Set("year", nil)
 
-	os.Args = []string{"cobra", "init", projectName}
-	if err := rootCmd.Execute(); err != nil {
-		t.Fatal("Error by execution:", err)
+	wd, _ := os.Getwd()
+	project := &Project{
+		AbsolutePath: fmt.Sprintf("%s/testproject", wd),
+		PkgName:      "github.com/spf13/testproject",
+		Legal:        getLicense(),
+		Copyright:    copyrightLine(),
+		Viper:        true,
+		AppName:      "testproject",
 	}
 
-	expectedFiles := []string{".", "cmd", "LICENSE", "main.go", "cmd/root.go"}
-	gotFiles := []string{}
+	err := project.Create()
+	if err != nil {
+		t.Fatal(err)
+	}
 
-	// Check project file hierarchy and compare the content of every single file
-	// with appropriate golden file.
-	err := filepath.Walk(project.AbsPath(), func(path string, info os.FileInfo, err error) error {
-		if err != nil {
-			return err
+	defer func() {
+		if _, err := os.Stat(project.AbsolutePath); err == nil {
+			os.RemoveAll(project.AbsolutePath)
 		}
+	}()
 
-		// Make path relative to project.AbsPath().
-		// E.g. path = "/home/user/go/src/github.com/spf13/testproject/cmd/root.go"
-		// then it returns just "cmd/root.go".
-		relPath, err := filepath.Rel(project.AbsPath(), path)
+	expectedFiles := []string{"LICENSE", "main.go", "cmd/root.go"}
+	for _, f := range expectedFiles {
+		generatedFile := fmt.Sprintf("%s/%s", project.AbsolutePath, f)
+		goldenFile := fmt.Sprintf("testdata/%s.golden", filepath.Base(f))
+		err := compareFiles(generatedFile, goldenFile)
 		if err != nil {
-			return err
+			t.Fatal(err)
 		}
-		relPath = filepath.ToSlash(relPath)
-		gotFiles = append(gotFiles, relPath)
-		goldenPath := filepath.Join("testdata", filepath.Base(path)+".golden")
-
-		switch relPath {
-		// Known directories.
-		case ".", "cmd":
-			return nil
-		// Known files.
-		case "LICENSE", "main.go", "cmd/root.go":
-			if *update {
-				got, err := ioutil.ReadFile(path)
-				if err != nil {
-					return err
-				}
-				if err := ioutil.WriteFile(goldenPath, got, 0644); err != nil {
-					t.Fatal("Error while updating file:", err)
-				}
-			}
-			return compareFiles(path, goldenPath)
-		}
-		// Unknown file.
-		return errors.New("unknown file: " + path)
-	})
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// Check if some files lack.
-	if err := checkLackFiles(expectedFiles, gotFiles); err != nil {
-		t.Fatal(err)
 	}
 }
diff --git a/cobra/cmd/project_test.go b/cobra/cmd/project_test.go
index 037f7c5..ed5b054 100644
--- a/cobra/cmd/project_test.go
+++ b/cobra/cmd/project_test.go
@@ -1,24 +1,3 @@
 package cmd
 
-import (
-	"testing"
-)
-
-func TestFindExistingPackage(t *testing.T) {
-	path := findPackage("github.com/spf13/cobra")
-	if path == "" {
-		t.Fatal("findPackage didn't find the existing package")
-	}
-	if !hasGoPathPrefix(path) {
-		t.Fatalf("%q is not in GOPATH, but must be", path)
-	}
-}
-
-func hasGoPathPrefix(path string) bool {
-	for _, srcPath := range srcPaths {
-		if filepathHasPrefix(path, srcPath) {
-			return true
-		}
-	}
-	return false
-}
+/* todo: write tests */
diff --git a/cobra/cmd/testdata/main.go.golden b/cobra/cmd/testdata/main.go.golden
index cdbe38d..4ad570c 100644
--- a/cobra/cmd/testdata/main.go.golden
+++ b/cobra/cmd/testdata/main.go.golden
@@ -1,21 +1,22 @@
-// Copyright © 2017 NAME HERE <EMAIL ADDRESS>
-//
-// 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.
+/*
+Copyright © 2019 NAME HERE <EMAIL ADDRESS>
 
+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 main
 
 import "github.com/spf13/testproject/cmd"
 
 func main() {
-	cmd.Execute()
+  cmd.Execute()
 }
diff --git a/cobra/cmd/testdata/root.go.golden b/cobra/cmd/testdata/root.go.golden
index d74f4cd..d3b889b 100644
--- a/cobra/cmd/testdata/root.go.golden
+++ b/cobra/cmd/testdata/root.go.golden
@@ -1,89 +1,97 @@
-// Copyright © 2017 NAME HERE <EMAIL ADDRESS>
-//
-// 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.
+/*
+Copyright © 2019 NAME HERE <EMAIL ADDRESS>
 
+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 cmd
 
 import (
-	"fmt"
-	"os"
+  "fmt"
+  "os"
+  "github.com/spf13/cobra"
+
+  homedir "github.com/mitchellh/go-homedir"
+  "github.com/spf13/viper"
 
-	homedir "github.com/mitchellh/go-homedir"
-	"github.com/spf13/cobra"
-	"github.com/spf13/viper"
 )
 
+
 var cfgFile string
 
+
 // rootCmd represents the base command when called without any subcommands
 var rootCmd = &cobra.Command{
-	Use:   "testproject",
-	Short: "A brief description of your application",
-	Long: `A longer description that spans multiple lines and likely contains
+  Use:   "testproject",
+  Short: "A brief description of your application",
+  Long: `A longer description that spans multiple lines and likely contains
 examples and usage of using your application. For example:
 
 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.`,
-	// Uncomment the following line if your bare application
-	// has an action associated with it:
-	//	Run: func(cmd *cobra.Command, args []string) { },
+  // Uncomment the following line if your bare application
+  // has an action associated with it:
+  //	Run: func(cmd *cobra.Command, args []string) { },
 }
 
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
-	if err := rootCmd.Execute(); err != nil {
-		fmt.Println(err)
-		os.Exit(1)
-	}
+  if err := rootCmd.Execute(); err != nil {
+    fmt.Println(err)
+    os.Exit(1)
+  }
 }
 
 func init() {
-	cobra.OnInitialize(initConfig)
+  cobra.OnInitialize(initConfig)
+
+  // Here you will define your flags and configuration settings.
+  // Cobra supports persistent flags, which, if defined here,
+  // will be global for your application.
 
-	// Here you will define your flags and configuration settings.
-	// Cobra supports persistent flags, which, if defined here,
-	// will be global for your application.
-	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.testproject.yaml)")
+  rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.testproject.yaml)")
 
-	// Cobra also supports local flags, which will only run
-	// when this action is called directly.
-	rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
+
+  // Cobra also supports local flags, which will only run
+  // when this action is called directly.
+  rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
 }
 
+
 // initConfig reads in config file and ENV variables if set.
 func initConfig() {
-	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 ".testproject" (without extension).
-		viper.AddConfigPath(home)
-		viper.SetConfigName(".testproject")
-	}
-
-	viper.AutomaticEnv() // read in environment variables that match
-
-	// If a config file is found, read it in.
-	if err := viper.ReadInConfig(); err == nil {
-		fmt.Println("Using config file:", viper.ConfigFileUsed())
-	}
+  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 ".testproject" (without extension).
+    viper.AddConfigPath(home)
+    viper.SetConfigName(".testproject")
+  }
+
+  viper.AutomaticEnv() // read in environment variables that match
+
+  // If a config file is found, read it in.
+  if err := viper.ReadInConfig(); err == nil {
+    fmt.Println("Using config file:", viper.ConfigFileUsed())
+  }
 }
+
diff --git a/cobra/cmd/testdata/test.go.golden b/cobra/cmd/testdata/test.go.golden
index ed64427..fb8e0fa 100644
--- a/cobra/cmd/testdata/test.go.golden
+++ b/cobra/cmd/testdata/test.go.golden
@@ -1,17 +1,18 @@
-// Copyright © 2017 NAME HERE <EMAIL ADDRESS>
-//
-// 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.
+/*
+Copyright © 2019 NAME HERE <EMAIL ADDRESS>
 
+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 cmd
 
 import (
diff --git a/powershell_completions_test.go b/powershell_completions_test.go
new file mode 100644
index 0000000..29b609d
--- /dev/null
+++ b/powershell_completions_test.go
@@ -0,0 +1,122 @@
+package cobra
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestPowerShellCompletion(t *testing.T) {
+	tcs := []struct {
+		name                string
+		root                *Command
+		expectedExpressions []string
+	}{
+		{
+			name: "trivial",
+			root: &Command{Use: "trivialapp"},
+			expectedExpressions: []string{
+				"Register-ArgumentCompleter -Native -CommandName 'trivialapp' -ScriptBlock",
+				"$command = @(\n        'trivialapp'\n",
+			},
+		},
+		{
+			name: "tree",
+			root: func() *Command {
+				r := &Command{Use: "tree"}
+
+				sub1 := &Command{Use: "sub1"}
+				r.AddCommand(sub1)
+
+				sub11 := &Command{Use: "sub11"}
+				sub12 := &Command{Use: "sub12"}
+
+				sub1.AddCommand(sub11)
+				sub1.AddCommand(sub12)
+
+				sub2 := &Command{Use: "sub2"}
+				r.AddCommand(sub2)
+
+				sub21 := &Command{Use: "sub21"}
+				sub22 := &Command{Use: "sub22"}
+
+				sub2.AddCommand(sub21)
+				sub2.AddCommand(sub22)
+
+				return r
+			}(),
+			expectedExpressions: []string{
+				"'tree'",
+				"[CompletionResult]::new('sub1', 'sub1', [CompletionResultType]::ParameterValue, '')",
+				"[CompletionResult]::new('sub2', 'sub2', [CompletionResultType]::ParameterValue, '')",
+				"'tree;sub1'",
+				"[CompletionResult]::new('sub11', 'sub11', [CompletionResultType]::ParameterValue, '')",
+				"[CompletionResult]::new('sub12', 'sub12', [CompletionResultType]::ParameterValue, '')",
+				"'tree;sub1;sub11'",
+				"'tree;sub1;sub12'",
+				"'tree;sub2'",
+				"[CompletionResult]::new('sub21', 'sub21', [CompletionResultType]::ParameterValue, '')",
+				"[CompletionResult]::new('sub22', 'sub22', [CompletionResultType]::ParameterValue, '')",
+				"'tree;sub2;sub21'",
+				"'tree;sub2;sub22'",
+			},
+		},
+		{
+			name: "flags",
+			root: func() *Command {
+				r := &Command{Use: "flags"}
+				r.Flags().StringP("flag1", "a", "", "")
+				r.Flags().String("flag2", "", "")
+
+				sub1 := &Command{Use: "sub1"}
+				sub1.Flags().StringP("flag3", "c", "", "")
+				r.AddCommand(sub1)
+
+				return r
+			}(),
+			expectedExpressions: []string{
+				"'flags'",
+				"[CompletionResult]::new('-a', 'a', [CompletionResultType]::ParameterName, '')",
+				"[CompletionResult]::new('--flag1', 'flag1', [CompletionResultType]::ParameterName, '')",
+				"[CompletionResult]::new('--flag2', 'flag2', [CompletionResultType]::ParameterName, '')",
+				"[CompletionResult]::new('sub1', 'sub1', [CompletionResultType]::ParameterValue, '')",
+				"'flags;sub1'",
+				"[CompletionResult]::new('-c', 'c', [CompletionResultType]::ParameterName, '')",
+				"[CompletionResult]::new('--flag3', 'flag3', [CompletionResultType]::ParameterName, '')",
+			},
+		},
+		{
+			name: "usage",
+			root: func() *Command {
+				r := &Command{Use: "usage"}
+				r.Flags().String("flag", "", "this describes the usage of the 'flag' flag")
+
+				sub1 := &Command{
+					Use:   "sub1",
+					Short: "short describes 'sub1'",
+				}
+				r.AddCommand(sub1)
+
+				return r
+			}(),
+			expectedExpressions: []string{
+				"[CompletionResult]::new('--flag', 'flag', [CompletionResultType]::ParameterName, 'this describes the usage of the ''flag'' flag')",
+				"[CompletionResult]::new('sub1', 'sub1', [CompletionResultType]::ParameterValue, 'short describes ''sub1''')",
+			},
+		},
+	}
+
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			buf := new(bytes.Buffer)
+			tc.root.GenPowerShellCompletion(buf)
+			output := buf.String()
+
+			for _, expectedExpression := range tc.expectedExpressions {
+				if !strings.Contains(output, expectedExpression) {
+					t.Errorf("Expected completion to contain %q somewhere; got %q", expectedExpression, output)
+				}
+			}
+		})
+	}
+}
diff --git a/zsh_completions_test.go b/zsh_completions_test.go
index 34e6949..e53fa88 100644
--- a/zsh_completions_test.go
+++ b/zsh_completions_test.go
@@ -2,88 +2,474 @@ package cobra
 
 import (
 	"bytes"
+	"regexp"
 	"strings"
 	"testing"
 )
 
-func TestZshCompletion(t *testing.T) {
+func TestGenZshCompletion(t *testing.T) {
+	var debug bool
+	var option string
+
 	tcs := []struct {
 		name                string
 		root                *Command
 		expectedExpressions []string
+		invocationArgs      []string
+		skip                string
 	}{
 		{
-			name:                "trivial",
-			root:                &Command{Use: "trivialapp"},
-			expectedExpressions: []string{"#compdef trivial"},
+			name: "simple command",
+			root: func() *Command {
+				r := &Command{
+					Use:  "mycommand",
+					Long: "My Command long description",
+					Run:  emptyRun,
+				}
+				r.Flags().BoolVar(&debug, "debug", debug, "description")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`(?s)function _mycommand {\s+_arguments \\\s+'--debug\[description\]'.*--help.*}`,
+				"#compdef _mycommand mycommand",
+			},
 		},
 		{
-			name: "linear",
+			name: "flags with both long and short flags",
 			root: func() *Command {
-				r := &Command{Use: "linear"}
-
-				sub1 := &Command{Use: "sub1"}
-				r.AddCommand(sub1)
-
-				sub2 := &Command{Use: "sub2"}
-				sub1.AddCommand(sub2)
-
-				sub3 := &Command{Use: "sub3"}
-				sub2.AddCommand(sub3)
+				r := &Command{
+					Use:  "testcmd",
+					Long: "long description",
+					Run:  emptyRun,
+				}
+				r.Flags().BoolVarP(&debug, "debug", "d", debug, "debug description")
 				return r
 			}(),
-			expectedExpressions: []string{"sub1", "sub2", "sub3"},
+			expectedExpressions: []string{
+				`'\(-d --debug\)'{-d,--debug}'\[debug description\]'`,
+			},
 		},
 		{
-			name: "flat",
+			name: "command with subcommands and flags with values",
 			root: func() *Command {
-				r := &Command{Use: "flat"}
-				r.AddCommand(&Command{Use: "c1"})
-				r.AddCommand(&Command{Use: "c2"})
+				r := &Command{
+					Use:  "rootcmd",
+					Long: "Long rootcmd description",
+				}
+				d := &Command{
+					Use:   "subcmd1",
+					Short: "Subcmd1 short description",
+					Run:   emptyRun,
+				}
+				e := &Command{
+					Use:  "subcmd2",
+					Long: "Subcmd2 short description",
+					Run:  emptyRun,
+				}
+				r.PersistentFlags().BoolVar(&debug, "debug", debug, "description")
+				d.Flags().StringVarP(&option, "option", "o", option, "option description")
+				r.AddCommand(d, e)
 				return r
 			}(),
-			expectedExpressions: []string{"(c1 c2)"},
+			expectedExpressions: []string{
+				`commands=\(\n\s+"help:.*\n\s+"subcmd1:.*\n\s+"subcmd2:.*\n\s+\)`,
+				`_arguments \\\n.*'--debug\[description]'`,
+				`_arguments -C \\\n.*'--debug\[description]'`,
+				`function _rootcmd_subcmd1 {`,
+				`function _rootcmd_subcmd1 {`,
+				`_arguments \\\n.*'\(-o --option\)'{-o,--option}'\[option description]:' \\\n`,
+			},
 		},
 		{
-			name: "tree",
+			name: "filename completion with and without globs",
 			root: func() *Command {
-				r := &Command{Use: "tree"}
-
-				sub1 := &Command{Use: "sub1"}
-				r.AddCommand(sub1)
-
-				sub11 := &Command{Use: "sub11"}
-				sub12 := &Command{Use: "sub12"}
-
-				sub1.AddCommand(sub11)
-				sub1.AddCommand(sub12)
+				var file string
+				r := &Command{
+					Use:   "mycmd",
+					Short: "my command short description",
+					Run:   emptyRun,
+				}
+				r.Flags().StringVarP(&file, "config", "c", file, "config file")
+				r.MarkFlagFilename("config")
+				r.Flags().String("output", "", "output file")
+				r.MarkFlagFilename("output", "*.log", "*.txt")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`\n +'\(-c --config\)'{-c,--config}'\[config file]:filename:_files'`,
+				`:_files -g "\*.log" -g "\*.txt"`,
+			},
+		},
+		{
+			name: "repeated variables both with and without value",
+			root: func() *Command {
+				r := genTestCommand("mycmd", true)
+				_ = r.Flags().BoolSliceP("debug", "d", []bool{}, "debug usage")
+				_ = r.Flags().StringArray("option", []string{}, "options")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`'\*--option\[options]`,
+				`'\(\*-d \*--debug\)'{\\\*-d,\\\*--debug}`,
+			},
+		},
+		{
+			name: "generated flags --help and --version should be created even when not executing root cmd",
+			root: func() *Command {
+				r := &Command{
+					Use:     "mycmd",
+					Short:   "mycmd short description",
+					Version: "myversion",
+				}
+				s := genTestCommand("sub1", true)
+				r.AddCommand(s)
+				return s
+			}(),
+			expectedExpressions: []string{
+				"--version",
+				"--help",
+			},
+			invocationArgs: []string{
+				"sub1",
+			},
+			skip: "--version and --help are currently not generated when not running on root command",
+		},
+		{
+			name: "zsh generation should run on root command",
+			root: func() *Command {
+				r := genTestCommand("root", false)
+				s := genTestCommand("sub1", true)
+				r.AddCommand(s)
+				return s
+			}(),
+			expectedExpressions: []string{
+				"function _root {",
+			},
+		},
+		{
+			name: "flag description with single quote (') shouldn't break quotes in completion file",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.Flags().Bool("private", false, "Don't show public info")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`--private\[Don'\\''t show public info]`,
+			},
+		},
+		{
+			name: "argument completion for file with and without patterns",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.MarkZshCompPositionalArgumentFile(1, "*.log")
+				r.MarkZshCompPositionalArgumentFile(2)
+				return r
+			}(),
+			expectedExpressions: []string{
+				`'1: :_files -g "\*.log"' \\\n\s+'2: :_files`,
+			},
+		},
+		{
+			name: "argument zsh completion for words",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.MarkZshCompPositionalArgumentWords(1, "word1", "word2")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`'1: :\("word1" "word2"\)`,
+			},
+		},
+		{
+			name: "argument completion for words with spaces",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.MarkZshCompPositionalArgumentWords(1, "single", "multiple words")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`'1: :\("single" "multiple words"\)'`,
+			},
+		},
+		{
+			name: "argument completion when command has ValidArgs and no annotation for argument completion",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.ValidArgs = []string{"word1", "word2"}
+				return r
+			}(),
+			expectedExpressions: []string{
+				`'1: :\("word1" "word2"\)'`,
+			},
+		},
+		{
+			name: "argument completion when command has ValidArgs and no annotation for argument at argPosition 1",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.ValidArgs = []string{"word1", "word2"}
+				r.MarkZshCompPositionalArgumentFile(2)
+				return r
+			}(),
+			expectedExpressions: []string{
+				`'1: :\("word1" "word2"\)' \\`,
+			},
+		},
+		{
+			name: "directory completion for flag",
+			root: func() *Command {
+				r := genTestCommand("root", true)
+				r.Flags().String("test", "", "test")
+				r.PersistentFlags().String("ptest", "", "ptest")
+				r.MarkFlagDirname("test")
+				r.MarkPersistentFlagDirname("ptest")
+				return r
+			}(),
+			expectedExpressions: []string{
+				`--test\[test]:filename:_files -g "-\(/\)"`,
+				`--ptest\[ptest]:filename:_files -g "-\(/\)"`,
+			},
+		},
+	}
 
-				sub2 := &Command{Use: "sub2"}
-				r.AddCommand(sub2)
+	for _, tc := range tcs {
+		t.Run(tc.name, func(t *testing.T) {
+			if tc.skip != "" {
+				t.Skip(tc.skip)
+			}
+			tc.root.Root().SetArgs(tc.invocationArgs)
+			tc.root.Execute()
+			buf := new(bytes.Buffer)
+			if err := tc.root.GenZshCompletion(buf); err != nil {
+				t.Error(err)
+			}
+			output := buf.Bytes()
 
-				sub21 := &Command{Use: "sub21"}
-				sub22 := &Command{Use: "sub22"}
+			for _, expr := range tc.expectedExpressions {
+				rgx, err := regexp.Compile(expr)
+				if err != nil {
+					t.Errorf("error compiling expression (%s): %v", expr, err)
+				}
+				if !rgx.Match(output) {
+					t.Errorf("expected completion (%s) to match '%s'", buf.String(), expr)
+				}
+			}
+		})
+	}
+}
 
-				sub2.AddCommand(sub21)
-				sub2.AddCommand(sub22)
+func TestGenZshCompletionHidden(t *testing.T) {
+	tcs := []struct {
+		name                string
+		root                *Command
+		expectedExpressions []string
+	}{
+		{
+			name: "hidden commands",
+			root: func() *Command {
+				r := &Command{
+					Use:   "main",
+					Short: "main short description",
+				}
+				s1 := &Command{
+					Use:    "sub1",
+					Hidden: true,
+					Run:    emptyRun,
+				}
+				s2 := &Command{
+					Use:   "sub2",
+					Short: "short sub2 description",
+					Run:   emptyRun,
+				}
+				r.AddCommand(s1, s2)
 
 				return r
 			}(),
-			expectedExpressions: []string{"(sub11 sub12)", "(sub21 sub22)"},
+			expectedExpressions: []string{
+				"sub1",
+			},
+		},
+		{
+			name: "hidden flags",
+			root: func() *Command {
+				var hidden string
+				r := &Command{
+					Use:   "root",
+					Short: "root short description",
+					Run:   emptyRun,
+				}
+				r.Flags().StringVarP(&hidden, "hidden", "H", hidden, "hidden usage")
+				if err := r.Flags().MarkHidden("hidden"); err != nil {
+					t.Errorf("Error setting flag hidden: %v\n", err)
+				}
+				return r
+			}(),
+			expectedExpressions: []string{
+				"--hidden",
+			},
 		},
 	}
 
 	for _, tc := range tcs {
 		t.Run(tc.name, func(t *testing.T) {
+			tc.root.Execute()
 			buf := new(bytes.Buffer)
-			tc.root.GenZshCompletion(buf)
+			if err := tc.root.GenZshCompletion(buf); err != nil {
+				t.Error(err)
+			}
 			output := buf.String()
 
-			for _, expectedExpression := range tc.expectedExpressions {
-				if !strings.Contains(output, expectedExpression) {
-					t.Errorf("Expected completion to contain %q somewhere; got %q", expectedExpression, output)
+			for _, expr := range tc.expectedExpressions {
+				if strings.Contains(output, expr) {
+					t.Errorf("Expected completion (%s) not to contain '%s' but it does", output, expr)
 				}
 			}
 		})
 	}
 }
+
+func TestMarkZshCompPositionalArgumentFile(t *testing.T) {
+	t.Run("Doesn't allow overwriting existing positional argument", func(t *testing.T) {
+		c := &Command{}
+		if err := c.MarkZshCompPositionalArgumentFile(1, "*.log"); err != nil {
+			t.Errorf("Received error when we shouldn't have: %v\n", err)
+		}
+		if err := c.MarkZshCompPositionalArgumentFile(1); err == nil {
+			t.Error("Didn't receive an error when trying to overwrite argument position")
+		}
+	})
+
+	t.Run("Refuses to accept argPosition less then 1", func(t *testing.T) {
+		c := &Command{}
+		err := c.MarkZshCompPositionalArgumentFile(0, "*")
+		if err == nil {
+			t.Fatal("Error was not thrown when indicating argument position 0")
+		}
+		if !strings.Contains(err.Error(), "position") {
+			t.Errorf("expected error message '%s' to contain 'position'", err.Error())
+		}
+	})
+}
+
+func TestMarkZshCompPositionalArgumentWords(t *testing.T) {
+	t.Run("Doesn't allow overwriting existing positional argument", func(t *testing.T) {
+		c := &Command{}
+		if err := c.MarkZshCompPositionalArgumentFile(1, "*.log"); err != nil {
+			t.Errorf("Received error when we shouldn't have: %v\n", err)
+		}
+		if err := c.MarkZshCompPositionalArgumentWords(1, "hello"); err == nil {
+			t.Error("Didn't receive an error when trying to overwrite argument position")
+		}
+	})
+
+	t.Run("Doesn't allow calling without words", func(t *testing.T) {
+		c := &Command{}
+		if err := c.MarkZshCompPositionalArgumentWords(0); err == nil {
+			t.Error("Should not allow saving empty word list for annotation")
+		}
+	})
+
+	t.Run("Refuses to accept argPosition less then 1", func(t *testing.T) {
+		c := &Command{}
+		err := c.MarkZshCompPositionalArgumentWords(0, "word")
+		if err == nil {
+			t.Fatal("Should not allow setting argument position less then 1")
+		}
+		if !strings.Contains(err.Error(), "position") {
+			t.Errorf("Expected error '%s' to contain 'position' but didn't", err.Error())
+		}
+	})
+}
+
+func BenchmarkMediumSizeConstruct(b *testing.B) {
+	root := constructLargeCommandHierarchy()
+	// if err := root.GenZshCompletionFile("_mycmd"); err != nil {
+	// 	b.Error(err)
+	// }
+
+	for i := 0; i < b.N; i++ {
+		buf := new(bytes.Buffer)
+		err := root.GenZshCompletion(buf)
+		if err != nil {
+			b.Error(err)
+		}
+	}
+}
+
+func TestExtractFlags(t *testing.T) {
+	var debug, cmdc, cmdd bool
+	c := &Command{
+		Use:  "cmdC",
+		Long: "Command C",
+	}
+	c.PersistentFlags().BoolVarP(&debug, "debug", "d", debug, "debug mode")
+	c.Flags().BoolVar(&cmdc, "cmd-c", cmdc, "Command C")
+	d := &Command{
+		Use:  "CmdD",
+		Long: "Command D",
+	}
+	d.Flags().BoolVar(&cmdd, "cmd-d", cmdd, "Command D")
+	c.AddCommand(d)
+
+	resC := zshCompExtractFlag(c)
+	resD := zshCompExtractFlag(d)
+
+	if len(resC) != 2 {
+		t.Errorf("expected Command C to return 2 flags, got %d", len(resC))
+	}
+	if len(resD) != 2 {
+		t.Errorf("expected Command D to return 2 flags, got %d", len(resD))
+	}
+}
+
+func constructLargeCommandHierarchy() *Command {
+	var config, st1, st2 string
+	var long, debug bool
+	var in1, in2 int
+	var verbose []bool
+
+	r := genTestCommand("mycmd", false)
+	r.PersistentFlags().StringVarP(&config, "config", "c", config, "config usage")
+	if err := r.MarkPersistentFlagFilename("config", "*"); err != nil {
+		panic(err)
+	}
+	s1 := genTestCommand("sub1", true)
+	s1.Flags().BoolVar(&long, "long", long, "long description")
+	s1.Flags().BoolSliceVar(&verbose, "verbose", verbose, "verbose description")
+	s1.Flags().StringArray("option", []string{}, "various options")
+	s2 := genTestCommand("sub2", true)
+	s2.PersistentFlags().BoolVar(&debug, "debug", debug, "debug description")
+	s3 := genTestCommand("sub3", true)
+	s3.Hidden = true
+	s1_1 := genTestCommand("sub1sub1", true)
+	s1_1.Flags().StringVar(&st1, "st1", st1, "st1 description")
+	s1_1.Flags().StringVar(&st2, "st2", st2, "st2 description")
+	s1_2 := genTestCommand("sub1sub2", true)
+	s1_3 := genTestCommand("sub1sub3", true)
+	s1_3.Flags().IntVar(&in1, "int1", in1, "int1 description")
+	s1_3.Flags().IntVar(&in2, "int2", in2, "int2 description")
+	s1_3.Flags().StringArrayP("option", "O", []string{}, "more options")
+	s2_1 := genTestCommand("sub2sub1", true)
+	s2_2 := genTestCommand("sub2sub2", true)
+	s2_3 := genTestCommand("sub2sub3", true)
+	s2_4 := genTestCommand("sub2sub4", true)
+	s2_5 := genTestCommand("sub2sub5", true)
+
+	s1.AddCommand(s1_1, s1_2, s1_3)
+	s2.AddCommand(s2_1, s2_2, s2_3, s2_4, s2_5)
+	r.AddCommand(s1, s2, s3)
+	r.Execute()
+	return r
+}
+
+func genTestCommand(name string, withRun bool) *Command {
+	r := &Command{
+		Use:   name,
+		Short: name + " short description",
+		Long:  "Long description for " + name,
+	}
+	if withRun {
+		r.Run = emptyRun
+	}
+
+	return r
+}