1. The first step in installing the Htop tool is to enable the EPEL repository.

# dnf install https://dl.Fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm _After installing the EPEL repository, update your system.# dnf update

 2. To install the htop tool, just run the following command:

# dnf install htopOnce installed, more information about htop can be found by running the command.# dnf info htop

 3. To start htop, just run the command.

# htop

Add rpmForge source to yum under CentOS, use yum to install htop 

Add rpmForge software source for CentOS

wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.3.4-1.el3.rf.x86_64.rpm rpm -Uvh rpmforge-release - 0.3.4-1.el3.rf.x86_64 
.rpm 

After the command is executed, two files are generated under /etc/yum.repos.d/ 

mirrors-rpmforge rpmforge.repo

Then just yum -y install htop