#Following the instructions at http://wiki.ros.org/melodic/Installation/Ubuntu

harry@harry-GE60-2QD:~$ sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
harry@harry-GE60-2QD:~$ sudo apt-key adv --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
Executing: /tmp/apt-key-gpghome.jUjq65I4yK/gpg.1.sh --keyserver hkp://ha.pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116
gpg: key 5523BAEEB01FA116: "ROS Builder <rosbuild@ros.org>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1
harry@harry-GE60-2QD:~$ sudo apt-get update
Ign:1 cdrom://Kubuntu 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.2) cosmic InRelease
Err:2 cdrom://Kubuntu 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.2) cosmic Release
  Please use apt-cdrom to allow APT to recognise this CD-ROM. 'apt-get update' cannot be used to add new CD-ROMs
Hit:3 http://gb.archive.ubuntu.com/ubuntu cosmic InRelease
Ign:4 http://dl.google.com/linux/chrome/deb stable InRelease
Get:5 http://gb.archive.ubuntu.com/ubuntu cosmic-updates InRelease [83.2 kB]
Hit:6 http://dl.google.com/linux/chrome/deb stable Release
Get:7 http://security.ubuntu.com/ubuntu cosmic-security InRelease [79.6 kB]
Hit:8 http://gb.archive.ubuntu.com/ubuntu cosmic-backports InRelease
Hit:10 http://archive.canonical.com/ubuntu cosmic InRelease
Ign:11 http://packages.ros.org/ros/ubuntu cosmic InRelease
Err:12 http://packages.ros.org/ros/ubuntu cosmic Release
  404  Not Found [IP: 140.211.166.134 80]
Reading package lists... Done
E: The repository 'cdrom://Kubuntu 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.2) cosmic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://packages.ros.org/ros/ubuntu cosmic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
harry@harry-GE60-2QD:~$