journalctl: show human readable text if no namespace is found

The common case will be that no namespaces are defined, hence by default
we'd just output "NAMESPACE" and exit, which is very confusing.

Generate a nice message instead, how many of our tools do it. Suppress
it on --quiet however.

diff --git a/src/journal/journalctl-misc.c b/src/journal/journalctl-misc.c
index c7a49eefea2a35e22a61c01ac10dd9bb64ce4675..9d878e8e0564b357ba46a1c9f919e3facad4540f 100644 (file)
--- a/src/journal/journalctl-misc.c
+++ b/src/journal/journalctl-misc.c
@@ -261,9 +261,14 @@ int action_list_namespaces(void) {
                 }
         }
 
-        r = table_print_with_pager(table, arg_json_format_flags, arg_pager_flags, !arg_quiet);
-        if (r < 0)
-                return table_log_print_error(r);
+        if (table_isempty(table) && FLAGS_SET(arg_json_format_flags, JSON_FORMAT_OFF)) {
+                if (!arg_quiet)
+                        log_notice("No namespaces found.");
+        } else {
+                r = table_print_with_pager(table, arg_json_format_flags, arg_pager_flags, !arg_quiet);
+                if (r < 0)
+                        return r;
+        }
 
         return 0;
 }