diff --git a/tiktok_hashtag_analysis/__main__.py b/tiktok_hashtag_analysis/__main__.py
index 8a9e5ee..3c3bbfd 100644
--- a/tiktok_hashtag_analysis/__main__.py
+++ b/tiktok_hashtag_analysis/__main__.py
@@ -6,6 +6,8 @@ from .base import TikTokDownloader, load_hashtags_from_file
 
 
 def create_parser():
+    """Create parser tp parse input command-line arguments."""
+
     parser = argparse.ArgumentParser(
         description="Analyze hashtags within posts scraped from TikTok."
     )
@@ -51,12 +53,20 @@ def create_parser():
         help="Directory to save scraped data and visualizations to",
         default=Path(".").resolve().parent / "data",
     )
+    parser.add_argument(
+        "--config",
+        type=str,
+        help="File name of configuration file to store TikTok credentials to",
+        default=None,
+    )
     parser.add_argument("--log", type=str, help="File to write logs to", default=None)
 
     return parser
 
 
 def main():
+    """Parse and process command-line arguments, scrape specified hashtags, and perform specified analyses."""
+
     parser = create_parser()
     args = parser.parse_args()
 
@@ -79,7 +89,9 @@ def main():
     else:
         hashtags = args.hashtags
 
-    downloader = TikTokDownloader(hashtags=hashtags, data_dir=args.output_dir)
+    downloader = TikTokDownloader(
+        hashtags=hashtags, data_dir=args.output_dir, config_file=args.config
+    )
 
     downloader.run(
         download=args.download, plot=args.plot, table=args.table, number=args.number
diff --git a/tiktok_hashtag_analysis/auth.py b/tiktok_hashtag_analysis/auth.py
index 17b8f3c..5d5ac16 100644
--- a/tiktok_hashtag_analysis/auth.py
+++ b/tiktok_hashtag_analysis/auth.py
@@ -2,17 +2,22 @@ import os
 import configparser
 from pathlib import Path
 import logging
+from typing import Optional
 
 
 class Authorization:
     """Handle authorization for TikTok, using the `msToken`."""
 
-    def __init__(self):
-        self.config_file = Path.home() / ".tiktok"
-        self.section = "TikTok"
-        self.ms_token = None
+    def __init__(self, config_file: Optional[str] = None):
+        if config_file:
+            self.config_file = Path(config_file)
+        else:
+            self.config_file = Path.home() / ".tiktok"
 
-    def get_token(self):
+        self.section = "TikTok"
+        self.get_token()
+
+    def get_token(self) -> str:
         """Load the "msToken" cookie taken from TikTok, which the scraper requires."""
 
         # Step 1: check if MS_TOKEN is defined as environment variable
@@ -37,14 +42,14 @@ class Authorization:
 
         return self.ms_token
 
-    def load_token(self):
+    def load_token(self) -> Optional[str]:
         """Parse a config file and extract the token."""
 
         config = configparser.ConfigParser()
         config.read(self.config_file)
         return config.get(section=self.section, option="MS_TOKEN", fallback=None)
 
-    def dump_token(self, ms_token):
+    def dump_token(self, ms_token: str):
         """Write the token to a config file."""
 
         config = configparser.ConfigParser()
@@ -52,10 +57,10 @@ class Authorization:
         config.add_section(self.section)
         config.set(section=self.section, option="MS_TOKEN", value=ms_token)
 
-        with open(self.config_file, "w") as f:
+        with open(self.config_file, "w", encoding="utf-8") as f:
             config.write(f)
 
-    def input_token(self):
+    def input_token(self) -> str:
         """Allow user to manually enter the token in the terminal."""
 
         print(
diff --git a/tiktok_hashtag_analysis/base.py b/tiktok_hashtag_analysis/base.py
index 74df81b..77623a3 100644
--- a/tiktok_hashtag_analysis/base.py
+++ b/tiktok_hashtag_analysis/base.py
@@ -17,6 +17,8 @@ import seaborn as sns
 
 from TikTokApi import TikTokApi
 
+from .auth import Authorization
+
 warnings.filterwarnings("ignore", message="Glyph (.*) missing from current font")
 sns.set_theme(style="darkgrid")
 
@@ -38,13 +40,11 @@ def load_hashtags_from_file(file: str) -> List[str]:
     return process_hashtag_list(hashtags=hashtags)
 
 
-async def _fetch_hashtag_data(hashtag: str) -> List[Dict]:
+async def _fetch_hashtag_data(hashtag: str, ms_token: str) -> List[Dict]:
     """Fetch data for videos containing a specified hashtag, asynchronously."""
     data = []
     async with TikTokApi() as api:
-        await api.create_sessions(
-            ms_tokens=[os.environ["MS_TOKEN"]], num_sessions=1, sleep_after=3
-        )
+        await api.create_sessions(ms_tokens=[ms_token], num_sessions=1, sleep_after=3)
         async for video in api.hashtag(name=hashtag).videos(count=1000):
             data.append(video.as_dict)
     return data
@@ -101,13 +101,16 @@ def aggregate_cooccurring_hashtags(hashtag_file: Path) -> Counter:
 class TikTokDownloader:
     """Main class for scraping data from TikTok."""
 
-    def __init__(self, hashtags: List[str], data_dir: str):
+    def __init__(self, hashtags: List[str], data_dir: str, config_file: str = None):
         self.hashtags = process_hashtag_list(hashtags)
         logging.info(f"Hashtags to scrape: {hashtags}")
 
         self.data_dir = Path(data_dir)
         os.makedirs(self.data_dir, exist_ok=True)
 
+        self.auth = Authorization(config_file=config_file)
+        self.ms_token = self.auth.ms_token
+
     def get_hashtag_posts(self, hashtag: str):
         """Fetch data about posts that used a specified hashtag and merge with
         existing data, if it exists."""
@@ -125,7 +128,9 @@ class TikTokDownloader:
             already_fetched_data = []
 
         # Scrape posts that use the specified hashtag
-        fetched_data = asyncio.run(_fetch_hashtag_data(hashtag=hashtag))
+        fetched_data = asyncio.run(
+            _fetch_hashtag_data(hashtag=hashtag, ms_token=self.ms_token)
+        )
         if len(fetched_data) == 0:
             logging.warning(f"No posts were found for the hashtag: {hashtag}")