1. Create a file login.properties in this directory, with your credentials:

email=info@example.com
password=secret

2. Compile the source code:

javac -cp ".:lib/*" com/stackexchange/toolbox/chat/MessagePoster.java

3. Run the program, with two arguments: the ID of the room, and the message you want to post. The example below posts This is a test. in the Sandbox chatroom.

java -cp ".:lib/*" com.stackexchange.toolbox.chat.MessagePoster 1 "This is a test."