Enumerate Roku devices
sudo nmap -sV -O -n 192.168.X.X/24
Identify the device and other stuff using netcat on the SSDP multicast address, port 1900.
nc -u 239.255.255.250 1900 < Roku_Enum.txt
If the Roku accepts ECP (External Control Protocol) we can use the REST API to the Roku's built in webserver.
The commands are listed here: https://developer.roku.com/docs/developer-program/debugging/external-control-api.md I highly recommend the documentation there for "deep linking" and other stuff to make Roku more fun.
Example viewing everything you could want to know about the device:
http://192.168.X.X:8060/query/device-info
You can also issue commands like a remote:
# Supported keys:
# Home
# Rev
# Fwd
# Play
# Select
# Left
# Right
# Down
# Up
# Back
# InstantReplay
# Info
# Backspace
# Search
# Enter
curl -d '' http://192.168.x.x:8060/keypress/select
Make Roku search for a movie:
curl -d '' http://192.168.1.76:8060/search/browse?keyword=Some%20Crap