Get ID from command line

downloader.py

@@ -20,16 +20,25 @@ import requests
 from bs4 import BeautifulSoup as bs
 from os import mkdir
 from os.path import exists
+from sys import argv
 
 ### Copyleft message
 
 print("""Copyleft ilikecats <ilikecats@sdf.org>
 This program is licensed under the GNU GPL v3-or-later.""")
 
-### Set this to the comic id.
-### TODO command line arg
+### Set this to the comic id or `False` (False means get ID from command  line)
 
-comic_id = "breaking-cat-news"
+comic_id = False
+
+### If comic_id is false, get id from command line. If command line has no args,
+### exit with error.
+if comic_id == False:
+    if len(argv) == 2:
+        comic_id = argv[1]
+    else:
+        print("Error: Comic ID not provided via command line. Set ID in source or provide ID.")
+        exit(1)
 
 ### Check   that   comic   actually  exists  (bonus:  gocomics  does  the  input
 ### sanitization  for  you;  as  long  as it exists, you can assume the input is