Running this script you will get the chat_id of the telegram conversation with your bot.
Python3 required.
python3 chatid.py <BotId>
Or, if your python path is /usr/bin/env python3, just:
./chatid.py <BotId>
The <BotId> is the token that BotFather give you when the bot is created.
./chatid.py XX:YYY-YYY
botId: XX:YYY-YYY
HTTP response code: 200
ChatId: 372472551