htop is an interactive process viewer for Linux, which is a powerful alternative to the start ‘top’ utility. Some of the benefits of htop:

Supports mouse interactions
Better sorting and selective display
Color formatted display
Resource graphs
Process treeview

Installing htop
To install htop to Redhat or CentOS (5.X) Linux easily via the yum package manager, the rpmforge package repository must be installed. To install, retrieve, and install the following RPM for your architecture (32bit or 64bit).

32-bit
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.i386.rpm
rpm -Uhv rpmforge-release*.rf.i386.rpm

64-bit
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el5.rf.x86_64.rpm
rpm -Uhv rpmforge-release*.rf.x86_64.rpm

Now that the rpmforge repository is installed, you can install the htop package easily via yum by typing: yum install htop