Linux top is very useful in seeing system processes. The only problem is the general layout and commands are not obvious while its open. For those reasons, I like htop (htop – interactive process viewer). It lists many options on the bottom of the screen and you can press the letter h to get more detailed information. Once in the application, you can press f5 to activate tree view or you can press the period key to change the sorting column. I also use the f4 key a lot to activate the search functionality. HTop is definitely a must-have application
In a Debian based Linux distro like Ubuntu, Gnome, Kubuntu and plenty more just run this comment below which will install it because htop is not installed by default.