diff --git a/common/config.go b/common/config.go
index 4d1a240..6105f67 100644
--- a/common/config.go
+++ b/common/config.go
@@ -10,6 +10,9 @@ import (
 	"github.com/mitchellh/go-homedir"
 )
 
+/*
+VERSION shows the version of RRH.
+*/
 const VERSION = "0.2"
 
 const (
@@ -39,6 +42,9 @@ const (
 	Ignore          = "IGNORE"
 )
 
+/*
+Config shows the values of configuration variables.
+*/
 type Config struct {
 	Home             string `json:"rrh_home"`
 	AutoDeleteGroup  string `json:"rrh_auto_delete_group"`
@@ -56,6 +62,10 @@ func (config *Config) isOnErrorIgnoreOrWarn() bool {
 	return onError == Ignore || onError == Warn
 }
 
+/*
+PrintErrors prints errors and returns the status code by following the value of RrhOnError.
+If the value of RrhOnError is Ignore or Warn, this method returns 0, otherwise, non-zero value.
+*/
 func (config *Config) PrintErrors(errs []error) int {
 	if config.GetValue(RrhOnError) != Ignore {
 		for _, err := range errs {
@@ -85,6 +95,9 @@ func availableValueOnError(value string) (string, error) {
 	return "", fmt.Errorf("%s: Unknown value of RRH_ON_ERROR (must be %s, %s, %s, or %s)", value, Fail, FailImmediately, Warn, Ignore)
 }
 
+/*
+Update method updates the config value with the given `value`.
+*/
 func (config *Config) Update(label string, value string) error {
 	switch label {
 	case RrhAutoDeleteGroup:
@@ -124,11 +137,15 @@ func (config *Config) Update(label string, value string) error {
 		}
 		return err
 	case RrhConfigPath:
-		return fmt.Errorf("%s: does not set on config file. set on environment.", label)
+		return fmt.Errorf("%s: does not set on config file. set on environment", label)
 	}
 	return fmt.Errorf("%s: Unknown variable name", label)
 }
 
+/*
+IsSet returns the bool value of the given label.
+If the label is not RrhAutoCreateGroup, RrhAutoDeleteGroup, and RrhSortOnUpdating, this method always returns false.
+*/
 func (config *Config) IsSet(label string) bool {
 	var value = config.GetValue(label)
 	if label != RrhAutoCreateGroup && label != RrhAutoDeleteGroup && label != RrhSortOnUpdating {
@@ -137,16 +154,25 @@ func (config *Config) IsSet(label string) bool {
 	return strings.ToLower(value) == "true"
 }
 
+/*
+GetValue returns the value of the given variable name.
+*/
 func (config *Config) GetValue(label string) string {
 	var value, _ = config.GetString(label)
 	return value
 }
 
+/*
+GetDefaultValue returns the default value of the given variable name.
+*/
 func (config *Config) GetDefaultValue(label string) string {
 	var value, _ = config.findDefaultValue(label)
 	return value
 }
 
+/*
+GetString returns the value of the given variable name and the definition part of the value.
+*/
 func (config *Config) GetString(label string) (value string, readFrom string) {
 	switch label {
 	case RrhAutoDeleteGroup:
@@ -215,6 +241,9 @@ func configPath() string {
 	return home
 }
 
+/*
+StoreConfig saves the store.
+*/
 func (config *Config) StoreConfig() error {
 	var configPath = config.GetValue(RrhConfigPath)
 	var err1 = CreateParentDir(configPath)
@@ -228,6 +257,10 @@ func (config *Config) StoreConfig() error {
 	return err2
 }
 
+/*
+OpenConfig reads the config file and returns it.
+The load path is based on `RrhConfigPath` of the environment variables.
+*/
 func OpenConfig() *Config {
 	bytes, err := ioutil.ReadFile(configPath())
 	if err != nil {
diff --git a/common/config_test.go b/common/config_test.go
index 660b9b5..8c1b758 100644
--- a/common/config_test.go
+++ b/common/config_test.go
@@ -80,7 +80,7 @@ func TestConfigUnset(t *testing.T) {
 	baseConfig.StoreConfig()
 }
 
-func ExampleConfigCommand_Run() {
+func ExampleConfigCommand() {
 	os.Setenv(RrhConfigPath, "../testdata/config.json")
 	os.Setenv(RrhHome, "../testdata/")
 	var command, _ = ConfigCommandFactory()
@@ -96,7 +96,7 @@ func ExampleConfigCommand_Run() {
 	// RRH_AUTO_DELETE_GROUP: false (config_file)
 	// RRH_SORT_ON_UPDATING: true (config_file)
 }
-func ExampleConfigCommand_Run_2() {
+func ExampleConfigCommand_Run() {
 	os.Setenv(RrhConfigPath, "../testdata/config.json")
 	os.Setenv(RrhHome, "../testdata/")
 	var command, _ = ConfigCommandFactory()
diff --git a/common/database.go b/common/database.go
index 5ba0638..a3d41d8 100644
--- a/common/database.go
+++ b/common/database.go
@@ -255,6 +255,9 @@ func (db *Database) ContainsCount(groupID string) int {
 	return groups[groupID]
 }
 
+/*
+FindRelationsOfGroup returns the repository ids belonging to the specified group.
+*/
 func (db *Database) FindRelationsOfGroup(groupId string) []string {
 	var repositories = []string{}
 	for _, relation := range db.Relations {
@@ -296,6 +299,9 @@ func (db *Database) Unrelate(groupID string, repoID string) {
 	db.Relations = newRelations
 }
 
+/*
+UnrelateRepository deletes all relations of the specified repository.
+*/
 func (db *Database) UnrelateRepository(repoID string) {
 	var newRelations = []Relation{}
 	for _, relation := range db.Relations {
@@ -306,6 +312,9 @@ func (db *Database) UnrelateRepository(repoID string) {
 	db.Relations = newRelations
 }
 
+/*
+UnrelateGroup deletes all relations about the specified group.
+*/
 func (db *Database) UnrelateFromGroup(groupID string) {
 	var newRelations = []Relation{}
 	for _, relation := range db.Relations {
diff --git a/common/rrhtime.go b/common/rrhtime.go
index 3073521..de93904 100644
--- a/common/rrhtime.go
+++ b/common/rrhtime.go
@@ -5,6 +5,9 @@ import (
 	"time"
 )
 
+/*
+RrhTime represents the time for RRH command, for marshaling a specific format.
+*/
 type RrhTime struct {
 	time time.Time
 }
diff --git a/fetch/fetch_all_cmd.go b/fetch/fetch_all_cmd.go
index 512893d..b8f1a1f 100644
--- a/fetch/fetch_all_cmd.go
+++ b/fetch/fetch_all_cmd.go
@@ -58,7 +58,7 @@ func (fetch *FetchAllCommand) printError(errs []error) {
 	}
 }
 
-func (fetch *FetchAllCommand) execFetch(db *common.Database, fetchOptions *FetchOptions) int {
+func (fetch *FetchAllCommand) execFetch(db *common.Database, fetchOptions *fetchOptions) int {
 	var onError = db.Config.GetValue(common.RrhOnError)
 
 	var fetch2 = FetchCommand{}
@@ -84,8 +84,8 @@ func (fetch *FetchAllCommand) execFetch(db *common.Database, fetchOptions *Fetch
 	return 0
 }
 
-func (fetch *FetchAllCommand) parse(args []string) (*FetchOptions, error) {
-	var options = FetchOptions{"origin", []string{}}
+func (fetch *FetchAllCommand) parse(args []string) (*fetchOptions, error) {
+	var options = fetchOptions{"origin", []string{}}
 	flags := flag.NewFlagSet("fetch-all", flag.ExitOnError)
 	flags.Usage = func() { fmt.Println(fetch.Help()) }
 	flags.StringVar(&options.remote, "r", "origin", "remote name")
diff --git a/fetch/fetch_cmd.go b/fetch/fetch_cmd.go
index 6d1ccad..415c78a 100644
--- a/fetch/fetch_cmd.go
+++ b/fetch/fetch_cmd.go
@@ -8,14 +8,23 @@ import (
 	"github.com/tamada/rrh/common"
 )
 
+/*
+FetchCommand represents a command.
+*/
 type FetchCommand struct {
-	options *FetchOptions
+	options *fetchOptions
 }
 
+/*
+FetchCommandFactory returns an instance of command.
+*/
 func FetchCommandFactory() (cli.Command, error) {
-	return &FetchCommand{}, nil
+	return &FetchCommand{&fetchOptions{}}, nil
 }
 
+/*
+Help returns the help message of the command.
+*/
 func (fetch *FetchCommand) Help() string {
 	return `rrh fetch [OPTIONS] [GROUPS...]
 OPTIONS
@@ -25,10 +34,16 @@ ARGUMENTS
                             if no value is specified, run on the default group.`
 }
 
+/*
+Synopsis returns the help message of the command.
+*/
 func (fetch *FetchCommand) Synopsis() string {
 	return "run \"git fetch\" on the given groups."
 }
 
+/*
+Run performs the command.
+*/
 func (fetch *FetchCommand) Run(args []string) int {
 	var fetchOptions, err = fetch.parse(args)
 	if err != nil {
@@ -65,7 +80,7 @@ func (fetch *FetchCommand) perform(db *common.Database) int {
 	return errorFlag
 }
 
-type FetchOptions struct {
+type fetchOptions struct {
 	remote string
 	// key      string
 	// userName string
@@ -73,8 +88,8 @@ type FetchOptions struct {
 	args []string
 }
 
-func (fetch *FetchCommand) parse(args []string) (*FetchOptions, error) {
-	var options = FetchOptions{"origin", []string{}}
+func (fetch *FetchCommand) parse(args []string) (*fetchOptions, error) {
+	var options = fetchOptions{"origin", []string{}}
 	flags := flag.NewFlagSet("fetch", flag.ExitOnError)
 	flags.Usage = func() { fmt.Println(fetch.Help()) }
 	flags.StringVar(&options.remote, "r", "origin", "remote name")
diff --git a/list/list_cmd.go b/list/list_cmd.go
index 22dfb87..848e131 100644
--- a/list/list_cmd.go
+++ b/list/list_cmd.go
@@ -98,21 +98,21 @@ func (options *listOptions) printRepo(repo Repo, result ListResult, formatString
 	fmt.Println()
 }
 
-func (options *listOptions) printSimple(result ListResult) bool {
-	if !options.noOmit && result.OmitList {
-		if len(result.Repos) == 1 {
-			fmt.Printf("%s (1 repository)\n", result.GroupName)
-		} else {
-			fmt.Printf("%s (%d repositories)\n", result.GroupName, len(result.Repos))
-		}
-		return true
+func (options *listOptions) isPrintSimple(result ListResult) bool {
+	return !options.noOmit && result.OmitList && len(options.args) == 0
+}
+
+func (options *listOptions) printRepositoryName(result ListResult) {
+	if len(result.Repos) == 1 {
+		fmt.Printf("%s (1 repository)\n", result.GroupName)
+	} else {
+		fmt.Printf("%s (%d repositories)\n", result.GroupName, len(result.Repos))
 	}
-	return false
 }
 
 func (options *listOptions) printResult(result ListResult) {
-	if !options.printSimple(result) {
-		fmt.Println(result.GroupName)
+	options.printRepositoryName(result)
+	if !options.isPrintSimple(result) {
 		if options.description || options.all {
 			fmt.Printf("    Description  %s", result.Description)
 			fmt.Println()
diff --git a/list/list_test.go b/list/list_test.go
index 1a36ea1..2198dc6 100644
--- a/list/list_test.go
+++ b/list/list_test.go
@@ -21,10 +21,10 @@ func ExampleListCommand_Run() {
 	var list, _ = ListCommandFactory()
 	list.Run([]string{"--desc", "--path"})
 	// Output:
-	// group1
+	// group1 (1 repository)
 	//     Description  desc1
 	//     repo1        path1
-	// group2
+	// group2 (0 repositories)
 	//     Description  desc2
 	// group3 (1 repository)
 }