Fix r2env use, listing installed versions

r2env/core.py

@@ -35,7 +35,8 @@ class R2Env:
         print_console(" [*] {0} ({1})".format(r2_version, r2_path))
 
     def show_config(self):
-        return json.dumps(self._config)
+        print_console("[*] Current r2env config:")
+        print_console(json.dumps(self._config))
 
     def list_available_packages(self):
         print_console("[*] List of available Radare packages")
@@ -70,8 +71,12 @@ class R2Env:
             return
         self._package_manager.uninstall_package(package)
 
-    def use(self, package):
+    def use(self, package=None):
         self.exit_if_r2env_not_initialized()
+        if not package:
+            print_console("[x] Package not defined. Please use 'r2env use' with one installed package. ", ERROR)
+            self.list_installed_packages()
+            return
         cur_ver = self._get_current_version()
         new_dst_dir = self._package_manager.get_package_path(package)
         if cur_ver:

r2env/repl.py

@@ -28,7 +28,7 @@ def show_help():
     print_console(HELP_MESSAGE)
 
 
-actions_with_argument = ["install", "uninstall", "use"]
+actions_with_argument = ["install", "uninstall"]
 actions = {
     "init": R2Env().init,
     "version": R2Env().get_r2_path,
@@ -58,7 +58,7 @@ def run_action(action, args, use_meson):
 
 def exit_if_not_argument_is_set(args):
     if len(args) < 1:
-        print_console("[x] Missing package argument.", ERROR)
+        print_console("[x] Missing package argument. ( as for example: radare2@latest)", ERROR)
         sys.exit(-1)