diff --git a/args.go b/args.go
index c4d820b8..e5a34c16 100644
--- a/args.go
+++ b/args.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 )
 
+// PositionalArgs defines positional arguments callback
 type PositionalArgs func(cmd *Command, args []string) error
 
 // Legacy arg validation has the following behaviour:
diff --git a/cobra.go b/cobra.go
index 6505c070..d01becc8 100644
--- a/cobra.go
+++ b/cobra.go
@@ -52,7 +52,7 @@ var EnableCommandSorting = true
 // if the CLI is started from explorer.exe.
 // To disable the mousetrap, just set this variable to blank string ("").
 // Works only on Microsoft Windows.
-var MousetrapHelpText string = `This is a command line tool.
+var MousetrapHelpText = `This is a command line tool.
 
 You need to open cmd.exe and run it from there.
 `
@@ -61,7 +61,7 @@ You need to open cmd.exe and run it from there.
 // if the CLI is started from explorer.exe. Set to 0 to wait for the return key to be pressed.
 // To disable the mousetrap, just set MousetrapHelpText to blank string ("").
 // Works only on Microsoft Windows.
-var MousetrapDisplayDuration time.Duration = 5 * time.Second
+var MousetrapDisplayDuration = 5 * time.Second
 
 // AddTemplateFunc adds a template function that's available to Usage and Help
 // template generation.
diff --git a/cobra/cmd/project.go b/cobra/cmd/project.go
index dd2f7ea2..a71cae31 100644
--- a/cobra/cmd/project.go
+++ b/cobra/cmd/project.go
@@ -2,9 +2,10 @@ package cmd
 
 import (
 	"fmt"
-	"github.com/spf13/cobra/cobra/tpl"
 	"os"
 	"text/template"
+
+	"github.com/spf13/cobra/cobra/tpl"
 )
 
 // Project contains name, license and paths to projects.
@@ -18,14 +19,15 @@ type Project struct {
 	AppName      string
 }
 
+// Command structure
 type Command struct {
 	CmdName   string
 	CmdParent string
 	*Project
 }
 
+// Create project receiver
 func (p *Project) Create() error {
-
 	// check if AbsolutePath exists
 	if _, err := os.Stat(p.AbsolutePath); os.IsNotExist(err) {
 		// create directory
@@ -80,6 +82,7 @@ func (p *Project) createLicenseFile() error {
 	return licenseTemplate.Execute(licenseFile, data)
 }
 
+// Create command receiver
 func (c *Command) Create() error {
 	cmdFile, err := os.Create(fmt.Sprintf("%s/cmd/%s.go", c.AbsolutePath, c.CmdName))
 	if err != nil {
diff --git a/cobra/tpl/main.go b/cobra/tpl/main.go
index 5e5a0fae..f6fe8977 100644
--- a/cobra/tpl/main.go
+++ b/cobra/tpl/main.go
@@ -1,5 +1,6 @@
 package tpl
 
+// MainTemplate defines main template string
 func MainTemplate() []byte {
 	return []byte(`/*
 {{ .Copyright }}
@@ -15,6 +16,7 @@ func main() {
 `)
 }
 
+// RootTemplate defines root template string
 func RootTemplate() []byte {
 	return []byte(`/*
 {{ .Copyright }}
@@ -108,6 +110,7 @@ func initConfig() {
 `)
 }
 
+// AddCommandTemplate defines add command template string
 func AddCommandTemplate() []byte {
 	return []byte(`/*
 {{ .Project.Copyright }}
diff --git a/command.go b/command.go
index 05fd9f34..ca6dc139 100644
--- a/command.go
+++ b/command.go
@@ -28,8 +28,8 @@ import (
 	flag "github.com/spf13/pflag"
 )
 
-// NotRunnable defines subcommand error
-var NotRunnable = errors.New("subcommand is required")
+// ErrSubCommandRequired defines subcommand error
+var ErrSubCommandRequired = errors.New("subcommand is required")
 
 // FParseErrWhitelist configures Flag parse errors to be ignored
 type FParseErrWhitelist flag.ParseErrorsWhitelist
@@ -232,7 +232,7 @@ func (c *Command) SetErr(newErr io.Writer) {
 	c.errWriter = newErr
 }
 
-// SetOut sets the source for input data
+// SetIn sets the source for input data
 // If newIn is nil, os.Stdin is used.
 func (c *Command) SetIn(newIn io.Reader) {
 	c.inReader = newIn
@@ -301,7 +301,7 @@ func (c *Command) ErrOrStderr() io.Writer {
 	return c.getErr(os.Stderr)
 }
 
-// ErrOrStderr returns output to stderr
+// InOrStdin returns output to stderr
 func (c *Command) InOrStdin() io.Reader {
 	return c.getIn(os.Stdin)
 }
@@ -790,7 +790,7 @@ func (c *Command) execute(a []string) (err error) {
 	}
 
 	if !c.Runnable() {
-		return NotRunnable
+		return ErrSubCommandRequired
 	}
 
 	c.preRun()
@@ -927,7 +927,7 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 		// If command wasn't runnable, show full help, but do return the error.
 		// This will result in apps by default returning a non-success exit code, but also gives them the option to
 		// handle specially.
-		if err == NotRunnable {
+		if err == ErrSubCommandRequired {
 			cmd.HelpFunc()(cmd, args)
 			return cmd, err
 		}
@@ -947,6 +947,7 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 	return cmd, err
 }
 
+// ValidateArgs validates arguments
 func (c *Command) ValidateArgs(args []string) error {
 	if c.Args == nil {
 		return nil
diff --git a/command_test.go b/command_test.go
index e7961c8f..b26bd4ab 100644
--- a/command_test.go
+++ b/command_test.go
@@ -836,7 +836,7 @@ func TestHelpExecutedOnNonRunnableChild(t *testing.T) {
 	rootCmd.AddCommand(childCmd)
 
 	output, err := executeCommand(rootCmd, "child")
-	if err != NotRunnable {
+	if err != ErrSubCommandRequired {
 		t.Errorf("Expected error")
 	}