Add basic setup and usage instructions

README.md

-# bulk_mailer
+# Bulk Mailer
 
-A little bulk e-mail program
\ No newline at end of file
+A little script that sends a bunch of e-mails at once.
+
+Sender-, SMTP- and recipient information is read from a YAML database (see [example](db.example.yml)), except for the SMTP password, which is prompted for.
+The message to send is read from a message template, opening and sender name are filled in and e-mails are sent one at a time.
+
+
+## Requirements
+
+* Python3
+* pyyaml
+
+### Installation
+
+To install pyyaml globally with pip:
+```
+pip3 install pyyaml
+```
+
+If you do not want to install it globally, you can use a Python virtual environment:
+```
+python3 -m venv venv
+. venv/bin/activate
+pip3 install pyyaml
+```
+In this case you must activate the virtual environment before running the script.
+
+
+## Usage
+
+Please see `./bulk_mailer.py --help` for usage information.
+
+
+## Limitations
+
+* The program assumes that the server uses STARTTLS (usually port 587).

bulk_mail.py

@@ -36,7 +36,7 @@ def parse_cmdline():
     parser = ArgumentParser(description=globals()['__doc__'])
     parser.add_argument('-v', '--verbose', action='store_true', help='enable verbose output')
     parser.add_argument('database', default='db.yml',
-                        help='YAML database containing sender and recipient information')
+                        help='YAML file containing sender- and recipient information')
     parser.add_argument('template', default='message.txt',
                         help='file containing message template')
     return parser.parse_args()