What It Does

Rainbarf is a small tool that displays your computer's CPU and memory usage as a colorful chart in your terminal's status bar. Instead of just showing numbers, it creates a visual bar graph that updates in real time, making it easy to spot when your system is under load at a glance.

How It Works

The tool monitors your CPU and RAM usage, then draws a horizontal bar chart using colored blocks. Each color represents a different type of memory: green for free memory, yellow for active memory, blue for inactive, red for wired memory, and so on. The chart scrolls like a stock ticker, showing CPU history over the last several minutes. If your laptop has a battery, rainbarf can also display the current charge level and remaining time on the right side of the bar. You configure it once in your terminal settings, and it updates automatically every time your terminal refreshes.

Who Uses It and Why

This is built specifically for people who use tmux (a terminal multiplexer that power users rely on for managing multiple terminal windows). Instead of constantly running a separate system monitor or keeping an eye on your Activity Monitor, you get a live dashboard built right into your terminal's footer. Developers, system administrators, and anyone who spends a lot of time in the terminal would find this useful—it's especially handy when you're running long processes and want to see if your machine is getting overwhelmed without switching windows.

Notable Details

Rainbarf is lightweight and written in Perl, which means it runs efficiently without eating the resources it's monitoring. It stores CPU history in a file so the chart persists across terminal sessions, and it works on Mac, Linux, and FreeBSD. The README mentions some quirks around color schemes depending on your terminal, but the tool includes options like RGB color mode and brightness adjustments to handle different setups.