diff --git a/shinigami/cli.py b/shinigami/cli.py
index e73a886..bc3c9db 100644
--- a/shinigami/cli.py
+++ b/shinigami/cli.py
@@ -59,14 +59,14 @@ def __init__(self) -> None:
         scan = subparsers.add_parser('scan', parents=[common], help='terminate processes on one or more clusters')
         scan.set_defaults(callable=Application.scan)
         scan.add_argument('-c', '--clusters', nargs='+', required=True, help='cluster names to scan')
-        scan.add_argument('-i', '--ignore-nodes', nargs='*', help='ignore given nodes')
+        scan.add_argument('-i', '--ignore-nodes', nargs='*', default=[], help='ignore given nodes')
         scan.add_argument('-u', '--uid-whitelist', nargs='+', type=loads, default=[0], help='user IDs to scan')
 
         # Subparser for the `Application.terminate` method
         terminate = subparsers.add_parser('terminate', parents=[common], help='terminate processes on a single node')
         terminate.set_defaults(callable=Application.terminate)
         terminate.add_argument('-n', '--nodes', nargs='+', required=True, help='the DNS name of the node to terminate')
-        terminate.add_argument('-u', '--uid-whitelist', nargs='+', type=loads, required=True, help='user IDs to scan')
+        terminate.add_argument('-u', '--uid-whitelist', nargs='+', type=loads, default=[0], help='user IDs to scan')
 
 
 class Application: