To install RuneScape NXT client in Ubuntu 18.04, run following commands as user root.
First become user root with command
Now run following commands one by one
echo "deb http://archive.ubuntu.com/ubuntu/ trusty main" > /etc/apt/sources.list.d/ubuntu_14.04_aka_trusty.temp.list apt-get update apt-get -y install libglew1.10 libpng12-0 rm /etc/apt/sources.list.d/ubuntu_14.04_aka_trusty.temp.list apt-get -y install libcurl3 wget -O - https://content.runescape.com/downloads/ubuntu/runescape.gpg.key | apt-key add - echo "deb [trusted=yes] https://content.runescape.com/downloads/ubuntu trusty non-free" > /etc/apt/sources.list.d/runescape.list apt-get update apt-get install -y runescape-launcher
Jagex need to update their game client and fix GPG key for the repository. Every time i do apt update, i get annoying GPG key error, i disabled RuneScape apt repository with
mv /etc/apt/sources.list.d/runescape.list /etc/apt/sources.list.d/runescape.list.disabled
This won’t get you updated RuneScape client, that jagex never update. So no big issue, you can re enable if they ever managed to do an update to Game client.