To install this very useful Linux monitoring tool on your Linux system, firstly add this line to your /etc/apt/sources.lst file. deb http://apt.izzysoft.de/ubuntu generic universedeb http://apt.izzysoft.de/ubuntu generic universe Then download the required GPG key for the apt packages. wget http://apt.izzysoft.de/izzysoft.ascwget http://apt.izzysoft.de/izzysoft.asc And then add this GPG key to apt. jason$ sudo apt-key add izzysoft.asc OKjason$ sudo …