Polybar — Fast and Customizable Status Bar for Linux

Introduction

Polybar is a status bar designed for use with tiling window managers like i3, bspwm, and Openbox. It emphasizes ease of configuration through a declarative INI format while remaining fast and resource-efficient, rendering information via a modular system of built-in and custom modules.

What Polybar Does

• Displays workspace indicators, window titles, and system tray
• Shows real-time system info: CPU, RAM, disk, temperature, network, battery
• Renders custom shell script output as first-class modules
• Supports fonts, colors, underlines, and per-module formatting via format strings
• Handles multi-monitor setups with per-output bar instances

Architecture Overview

Polybar is written in C++ and renders directly to an X11 window (or via XCB). Each bar is a single process that ticks modules at configurable intervals. Built-in modules query /proc, sysfs, or D-Bus for system data. Custom/script modules fork shell commands and parse their stdout. IPC commands allow external control via polybar-msg.

Self-Hosting & Configuration

• Install from package manager or compile from source (requires cmake, xcb libs)
• Config file lives at ~/.config/polybar/config.ini (INI format with sections per bar/module)
• Define bars with position, size, fonts, and a list of modules for left/center/right
• Create custom modules using type = custom/script with exec and interval keys
• Launch via a shell script called from your WM's startup (e.g., i3 exec_always)

Key Features

• Declarative INI configuration: no programming needed for common setups
• Rich built-in modules: i3/bspwm workspaces, ALSA/PulseAudio volume, MPRIS media
• Custom/script modules for displaying any shell command output
• IPC interface: send commands (hide, show, toggle module) from scripts
• Highly themeable with hex colors, gradients, ramp icons, and format overrides

Comparison with Similar Tools

• i3bar/swaybar — simpler, protocol-driven; less visual customization
• Waybar — Wayland-native alternative with similar module system; required for Sway/Hyprland
• lemonbar — minimal pipe-based bar; more flexible but harder to configure
• tint2 — panel for Openbox; supports taskbar but less module variety
• Eww (ElKowars Widgets) — Lisp-like config for arbitrary desktop widgets; steeper learning curve

FAQ

Q: Does Polybar work on Wayland? A: No. Polybar is X11-only. For Wayland compositors, use Waybar instead.

Q: How do I add a custom script module? A: Define a module section with type = custom/script, set exec = /path/to/script.sh and interval = 5.

Q: Can I use Nerd Font icons in Polybar? A: Yes. Add a Nerd Font as a secondary font in your bar config and reference glyphs in module labels.

Q: How do I reload the config without restarting? A: Polybar does not hot-reload. Use a launch script that kills existing instances and restarts the process.

Sources

• https://github.com/polybar/polybar
• https://polybar.github.io