Monitoring Your Linux Server with htop

🔍 Why use htop?

When your server slows down or you want to monitor the system activity in real-time, htop is a simple, effective, and visual tool. It’s a modern alternative to the top command.

With htop, you can:

• View CPU, memory, and swap usage
• Identify resource-intensive processes
• Sort, filter, and kill processes easily
• Use a colorful, interactive, and clear interface

🛠️ Installing htop

➤ On Debian / Ubuntu:

sudo apt update
sudo apt install htop

➤ On CentOS / RHEL / Fedora:

sudo dnf install htop  # or 'yum install htop' on CentOS 7

👁️‍🗨️ Understanding the htop interface

Simply run:

htop

You’ll see an interface split into two parts:

🧠 At the top:

• Colored CPU bars: each core is shown
• RAM and Swap usage
• Uptime: how long the system has been running

📋 At the bottom:

A list of running processes with:

• PID: process ID
• USER: who is running the process
• %CPU and %MEM: resource usage
• COMMAND: the command executed

🛠️ Useful Features in htop

• Sort: press F6 to choose sorting criteria (CPU, memory, etc.)
• Kill a process: use arrow keys to select, then press F9
• Search a process: F3 and type the name
• Show threads: press H
• Tree view: press F5 to toggle
• Customize display: F2 to configure colors, columns, etc.

🧪 Real-world example: “My server is slow…”

You SSH into your server and type htop:

• Is an app using 100% of the CPU? You’ll spot it easily.
• High memory usage? Maybe apache2 or mysql is misconfigured.
• Zombie processes? You’ll see them too.

🚀 Alternatives to htop

If you like htop, you might also enjoy:

Install glances:

sudo apt install glances          # Debian/Ubuntu
sudo dnf install glances          # CentOS/RHEL

✅ Conclusion

htop is one of the easiest tools to quickly understand what’s happening on your server. Whether you’re a beginner or an experienced sysadmin, it’s an essential daily companion.