To use the command line tool htop

To use the command line tool htop, you first need to install it on your system. On Ubuntu or Debian-based systems, you can use the command sudo apt-get install htop to install it. On Fedora or CentOS-based systems, use the command sudo yum install htop.

Once it is installed, you can open it by typing htop in your terminal. The interface displays a real-time view of the processes running on your system, including the process ID, user, CPU usage, and memory usage. You can use the arrow keys to navigate and the q key to exit the program.

You can also use various command line options when running htop. For example, you can use the -u option followed by a username to only show processes owned by that user, or use the -p option followed by a process ID to only show that specific process.

htop also provides many other features like filtering, sorting, process management and more, you can refer the man page of htop for more info.