How to generate CPU usage charts in the terminal

Why monitor your processor through the terminal?

When a computer starts freezing or a remote hosting server experiences sudden slowdowns, many people immediately reach for a graphical task manager. However, on Linux systems and remote servers, launching a graphical interface consumes significant RAM and CPU cycles precisely from the machine that is already overwhelmed. In practice, this means your diagnostic tool can actually worsen the exact problem you are trying to investigate, masking the real culprits behind the system slowdown.

This is precisely where command-line interface (CLI) tools shine. They are lightweight utilities running directly in your text terminal, consuming minimal resources. Besides being mandatory for managing remote servers via SSH connections, they offer instant visual feedback on what is happening under the hood. Before performing complex maintenance tasks or even attempting to test hardware components on the workbench, mastering terminal-based CPU monitoring ensures you observe the exact behavior of your processing cores.

Understanding the basics: the good old top command

The traditional utility across almost all Unix-based operating systems is the top command. Typing it in your terminal brings up a dynamic table refreshing every few seconds, listing running processes ordered by resource consumption. At the top section, you get a numerical summary of total CPU utilization broken down between user processes, operating system tasks, and idle time.

While extremely useful because it comes pre-installed on virtually every Linux distribution, top can be visually cluttered when you need a quick overview of performance spikes. It outputs raw numbers in plain text, forcing analysts to mentally correlate core behavior over time. For those preferring a more intuitive visualization without leaving the terminal, modern alternatives transform numerical data into dynamic, colorful graphs.

Htop and Btop: visual graphs right on your screen

If you want to turn raw text lines into colorful, easy-to-understand progress bars, htop is the natural successor to the classic command. It adds distinct colors to differentiate CPU usage across individual cores, while supporting mouse clicks to scroll through process lists or kill frozen tasks effortlessly. Another outstanding tool for deep investigations is btop, which renders historical charts for CPU, memory, and disks with an impressive visual interface.

These tools draw horizontal progress bars and Unicode character-based line graphs directly inside your terminal window. This allows you to immediately spot whether a single core is choking on a heavy task or if the workload is well-balanced across all available cores. For advanced performance analyses that can later be exported into reports, many engineers combine these visualizations with plotting utilities like specialized data plotting tools for long-term auditing.

Tracking spikes with simple one-liner commands

Sometimes you do not need a full interactive interface, but rather a quick way to record how your processor behaves while running a heavy script. For these scenarios, simple commands combined with system utilities help capture snapshot statistics of CPU load. The mpstat command, for instance, is part of the sysstat package and details processor usage statistically based on user-defined time intervals.

You can configure mpstat to print a status line every two seconds in your terminal, allowing you to pipe that output into a text file for later examination. If you need to correlate processing spikes with network disruptions or dropped TCP connections caused by connection floods, it pays to cross-reference that information using efficient TCP connection auditing commands. This helps you figure out whether high CPU usage stems from malicious network traffic or poorly optimized internal processes.

Conclusion and monitoring best practices

Mastering terminal-based CPU monitoring is a transformative skill for anyone working with operating systems, from dedicated server administrators to homelab enthusiasts. Tools like top, htop, and btop offer the perfect balance between operational lightweightness and visual clarity, allowing you to spot bottlenecks and processing spikes without taxing the target machine. By integrating these habits into your daily maintenance routine, you gain the autonomy to diagnose failures quickly and keep your computing environments stable and predictable.