diff --git a/src/corppa/utils/filter.py b/src/corppa/utils/filter.py
index 05e98e7..c919ce1 100644
--- a/src/corppa/utils/filter.py
+++ b/src/corppa/utils/filter.py
@@ -139,7 +139,7 @@ def main():
         print(
             f"Error: requested output file {args.output} already exists; not overwriting"
         )
-        exit(-1)
+        sys.exit(-1)
 
     try:
         save_filtered_corpus(