print usage on no arguments - graceful handle CTRL+C

get-iso

@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 #
 # @linux-aarhus - root.nix.dk
-# License: GNU GPL, version 3 or later; http://www.gnu.org/licenses/gpl.html
+# License: GNU GPL, version 3 or later; https://www.gnu.org/licenses/gpl.html
 import argparse
 import subprocess
 import sys
@@ -14,6 +14,9 @@ from pathlib import Path
 
 DEF_URL = "https://gitlab.manjaro.org/webpage/iso-info/-/raw/master/file-info.json"
 FOLDER = Path.home()
+PROG_NAME = os.path.basename(__file__)
+PROG_VERSION = "0.1"
+GNU_URL = "https://www.gnu.org/licenses/gpl.html"
 
 
 def download_file(url: str, folder_name: str) -> bool:
@@ -85,17 +88,15 @@ def download(url: str) -> bool:
     return success
 
 
-if __name__ == '__main__':
-    prog_name = os.path.basename(__file__)
-    prog_version = "0.1"
+def main():
     iso_files = init_iso_list(DEF_URL)
     choices = []
     for c in iso_files:
         choices.append(c["name"])
     parser = argparse.ArgumentParser(
-        prog=f"{prog_name}",
+        prog=f"{PROG_NAME}",
         description="This tool will download a named Manjaro ISO and verify the signature",
-        epilog=f"{prog_name} version {prog_version} - License GPL v3 or later")
+        epilog=f"{PROG_NAME} v. {PROG_VERSION} - GPL v3 or later <{GNU_URL}>")
     parser.add_argument("edition",
                         type=str,
                         help="edition e.g. plasma or xfce",
@@ -105,7 +106,8 @@ if __name__ == '__main__':
                         action="store_true",
                         help="Download full ISO")
     args = parser.parse_args()
-
+    if args.edition is None:
+        parser.print_usage()
     edition = [x for x in iso_files if args.edition == x["name"]]
     for x in edition:
         if args.full:
@@ -124,3 +126,11 @@ if __name__ == '__main__':
             print("Download ISO failed")
             sys.exit(0)
     sys.exit(0)
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        print("\n" + "Exit: interrupted by the user.")
+        sys.exit(1)