diff --git a/sort_known_hosts.py b/sort_known_hosts.py
index dd396ab..29bae13 100755
--- a/sort_known_hosts.py
+++ b/sort_known_hosts.py
@@ -2,8 +2,8 @@
 
 from __future__ import annotations
 
+import argparse
 import sys
-import os
 from pathlib import Path
 from collections import namedtuple
 
@@ -19,7 +19,7 @@ class Entry(namedtuple('Entry', ['host', 'algorithm', 'hash'])):
         return f'{self.algorithm}{self.separator}{self.hash}'
 
 
-def run(args) -> None:
+def run(args: argparse.Namespace) -> None:
     filename: Path = getattr(args, 'input', Path())
     file_path = filename.resolve()
     if not file_path.is_file():
@@ -73,20 +73,20 @@ def run(args) -> None:
         )
     )
     if output is None:
-        sys.stdout.write(output_lines)
+        for line in output_lines:
+            print(line, end='')
     else:
         output_file = output.resolve()
-        if not output_file.parent.exists():
-            os.makedirs(output_file.parent)
         if output_file.is_dir():
             print('Can not write to directory.')
+            sys.exit(1)
+        if not output_file.parent.exists():
+            output_file.parent.mkdir(parents=True)
         with output_file.open('w', encoding='utf-8') as wfp:
             wfp.writelines(output_lines)
 
 
 def main() -> None:
-    import argparse
-
     parser = argparse.ArgumentParser(
         formatter_class=argparse.ArgumentDefaultsHelpFormatter
     )
@@ -94,7 +94,7 @@ def main() -> None:
         '-i',
         '--input',
         type=Path,
-        default=f'{os.path.expanduser("~")}/.ssh/known_hosts',
+        default=f'{Path("~").expanduser()}/.ssh/known_hosts',
         help='file to read',
     )
     parser.add_argument('-o', '--output', type=Path, help='file to write')