push: improve 'no remote specified' hint

dvc/config.py

@@ -24,15 +24,7 @@ def __init__(self, msg):
 
 
 class NoRemoteError(ConfigError):
-    def __init__(self, command):
-        msg = (
-            "no remote specified. Setup default remote with\n"
-            "    dvc remote default <name>\n"
-            "or use:\n"
-            "    dvc {} -r <name>\n".format(command)
-        )
-
-        super().__init__(msg)
+    pass
 
 
 def supported_cache_type(types):

dvc/data_cloud.py

@@ -39,7 +39,26 @@ def get_remote(self, remote=None, command="<command>"):
         if remote:
             return self._init_remote(remote)
 
-        raise NoRemoteError(command)
+        has_non_default_remote = bool(
+            self.repo.config.list_options(
+                Config.SECTION_REMOTE_REGEX, Config.SECTION_REMOTE_URL
+            )
+        )
+
+        if has_non_default_remote:
+            error_msg = (
+                "no remote specified. Setup default remote with\n"
+                "    dvc remote default <remote name>\n"
+                "or use:\n"
+                "    dvc {} -r <remote name>".format(command)
+            )
+        else:
+            error_msg = (
+                "no remote specified. Create a default remote with\n"
+                "    dvc remote add -d <remote name> <remote url>"
+            )
+
+        raise NoRemoteError(error_msg)
 
     def _init_remote(self, remote):
         return Remote(self.repo, name=remote)