Don't always write default config, do it via defaults

README.md

@@ -20,6 +20,7 @@ your own risk.
 	download <appid...>   Download an app
 	install <appid...>    Install an app
 	uninstall <appid...>  Uninstall an app
+	defaults              Reset to the default settings
 
 ### Missing commands
 

cmd/fdroidcl/defaults.go

@@ -0,0 +1,41 @@
+// Copyright (c) 2015, Daniel Martí <mvdan@mvdan.cc>
+// See LICENSE for licensing information
+
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+)
+
+var cmdDefaults = &Command{
+	UsageLine: "defaults",
+	Short:     "Reset to the default settings",
+}
+
+func init() {
+	cmdDefaults.Run = runDefaults
+}
+
+func runDefaults(args []string) {
+	if len(args) > 0 {
+		log.Fatalf("No arguments allowed")
+	}
+	writeConfig(&config)
+}
+
+func writeConfig(c *userConfig) {
+	f, err := os.Create(configPath())
+	if err != nil {
+		log.Fatalf("Error when creating config file: %v", err)
+	}
+	defer f.Close()
+	b, err := json.MarshalIndent(c, "", "\t")
+	if err != nil {
+		log.Fatalf("Error when encoding config file: %v", err)
+	}
+	if _, err := f.Write(b); err != nil {
+		log.Fatalf("Error when writing config file: %v", err)
+	}
+}

cmd/fdroidcl/main.go

@@ -43,6 +43,10 @@ func mustConfig() string {
 	return subdir(dir, cmdName)
 }
 
+func configPath() string {
+	return filepath.Join(mustConfig(), "config.json")
+}
+
 type Repo struct {
 	ID  string `json:"id"`
 	URL string `json:"url"`
@@ -62,24 +66,11 @@ var config = userConfig{
 }
 
 func readConfig() {
-	p := filepath.Join(mustConfig(), "config.json")
-	f, err := os.Open(p)
+	f, err := os.Open(configPath())
 	if err != nil {
 		if !os.IsNotExist(err) {
 			log.Fatalf("Error when opening config file: %v", err)
 		}
-		f, err := os.Create(p)
-		if err != nil {
-			log.Fatalf("Error when creating config file: %v", err)
-		}
-		defer f.Close()
-		b, err := json.MarshalIndent(&config, "", "\t")
-		if err != nil {
-			log.Fatalf("Error when encoding config file: %v", err)
-		}
-		if _, err := f.Write(b); err != nil {
-			log.Fatalf("Error when writing config file: %v", err)
-		}
 		return
 	}
 	defer f.Close()
@@ -161,6 +152,7 @@ var commands = []*Command{
 	cmdDownload,
 	cmdInstall,
 	cmdUninstall,
+	cmdDefaults,
 }
 
 func main() {