Installing htop on Ubuntu
Installing on Ubuntu is as simple as apt-get… You can also grab the source from the htop site linked at the bottom of this article.
sudo apt-get install htop
Once installed, just type htop at a terminal to launch it, and notice the great text-mode graph at the top of the display:
But here’s the best part… just use your Up/Down arrow keys to select a process, and then you can kill it with the F9 key if you’d like, or you can change the priority by using the F7 and F8 keys. (note that you’ll have to be root to give anything really high priority).
You can also use the F6 key to change the default sort column really easily:
You can check the setup options for a lot more settings like which columns should show up by default. How to Geek