config: add show/file subcommands which print the config/its path (fixes #1086)

cmd/config/config.go

@@ -1,6 +1,9 @@
 package config
 
 import (
+	"fmt"
+	"os"
+
 	"github.com/ncw/rclone/cmd"
 	"github.com/ncw/rclone/fs"
 	"github.com/spf13/cobra"
@@ -11,10 +14,35 @@ func init() {
 }
 
 var commandDefintion = &cobra.Command{
-	Use:   "config",
+	Use:   "config [function]",
 	Short: `Enter an interactive configuration session.`,
+	Long: "`rclone config`" + `
+ enters an interactive configuration sessions where you can setup
+new remotes and manage existing ones. You may also set or remove a password to
+protect your configuration.
+
+Additional functions:
+
+  * ` + "`rclone config edit`" + ` – same as above
+  * ` + "`rclone config file`" + ` – show path of configuration file in use
+  * ` + "`rclone config show`" + ` – print (decrypted) config file
+`,
 	Run: func(command *cobra.Command, args []string) {
-		cmd.CheckArgs(0, 0, command, args)
+		cmd.CheckArgs(0, 1, command, args)
-		fs.EditConfig()
+		if len(args) == 0 {
+			fs.EditConfig()
+			return
+		}
+
+		switch args[0] {
+		case "edit":
+			fs.EditConfig()
+		case "show":
+			fs.ShowConfig()
+		case "file":
+			fs.ShowConfigLocation()
+		default:
+			fmt.Fprintf(os.Stderr, "Unknown subcommand %q, %s only supports edit, show and file.\n", args[0], command.Name())
+		}
 	},
 }

fs/config.go

@@ -436,6 +436,8 @@ func LoadConfig() {
 		configData, _ = goconfig.LoadFromReader(&bytes.Buffer{})
 	} else if err != nil {
 		log.Fatalf("Failed to load config file %q: %v", ConfigPath, err)
+	} else {
+		Debugf(nil, "Using config file from %q", ConfigPath)
 	}
 
 	// Load filters
@@ -1096,6 +1098,29 @@ func CopyRemote(name string) {
 	SaveConfig()
 }
 
+// ShowConfigLocation prints the location of the config file in use
+func ShowConfigLocation() {
+	if _, err := os.Stat(ConfigPath); os.IsNotExist(err) {
+		fmt.Println("Configuration file doesn't exist, but rclone will use this path:")
+	} else {
+		fmt.Println("Configuration file is stored at:")
+	}
+	fmt.Printf("%s\n", ConfigPath)
+}
+
+// ShowConfig prints the (unencrypted) config options
+func ShowConfig() {
+	var buf bytes.Buffer
+	if err := goconfig.SaveConfigData(configData, &buf); err != nil {
+		log.Fatalf("Failed to serialize config: %v", err)
+	}
+	str := buf.String()
+	if str == "" {
+		str = "; empty config\n"
+	}
+	fmt.Printf("%s", str)
+}
+
 // EditConfig edits the config file interactively
 func EditConfig() {
 	for {