Top shows you a great deal of information about the top running programs on your server, load averages, memory usage and more. Now imagine Top a little more colorful with some graphical representations of CPU, memory and swap usage, and a full range of shortcuts and functions that can help you manage tasks and find exactly what you need. Enter Htop, an alternative to Top that greatly expands its functionality.
To install htop on your RHEL, CentOS or Fedora system, you need to use the RepoForge repository. The easiest way is to download the appropriate RPM and install it. For example, for the 64-bit version of RHEL 6:
# wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
# rpm -ivh rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
Then install via yum:
# yum install htop
On a Debian or Ubuntu Server, it should be in the main repository. To install, type:
# apt-get install htop
At the top, you will see meters for each CPU/core, memory and swap. It will also show you the number of running tasks, the load average and uptime. The middle section will look nearly identical to top with PID, user, memory and cpu usage, and the commands. At the bottom, you have a menu with function key shortcuts that allow you to manipulate tasks. You can select tasks with your keyboard or mouse.
For more help with htop, press F1 within htop or see this documentation.