nixmon

A system monitor for the terminal, written in pure Nix. A btop clone that demonstrates advanced Nix programming techniques.

Features

• CPU usage with per-core breakdown and sparklines
• Memory and swap monitoring with visual progress bars
• Disk usage for mounted filesystems with usage percentages
• Network throughput with historical graphs and interface statistics
• Process list sorted by resource usage with filtering and selection
• Temperature sensors
• Battery status (macOS)
• Multiple color themes (default, nord, gruvbox, dracula, monokai, solarized)
• Auto-resize to fill terminal window
• Mouse support for scrolling and interaction
• Keyboard shortcuts for navigation and control

Requirements

• Nix with flakes enabled
• macOS or Linux

Installation

Quick Install (Recommended)

Install globally so you can run nixmon from anywhere, just like btop:

# From the nixmon directory
./install.sh

# Or from anywhere, pointing to the flake
./install.sh /path/to/nixmon

# Or install directly from GitHub (once published)
nix profile install github:0xatrilla/nixmon#nixmon

After installation, simply run:

nixmon

The nixmon command will be available in your PATH, just like any other system command.

Alternative: Run Without Installation

Run directly with Nix (no installation needed):

# From GitHub (once published)
nix run github:0xatrilla/nixmon

# Or from local directory
nix run .

Update

nix profile upgrade nixmon

Uninstall

nix profile remove nixmon

Configuration

Environment Variables

• NIXMON_THEME: Color theme (default, nord, gruvbox, dracula, monokai, solarized)
• NIXMON_REFRESH: Refresh interval in seconds (default: 2)

Example:

NIXMON_THEME=nord nixmon

Configuration File

Create ~/.config/nixmon/nixmon.conf (or $XDG_CONFIG_HOME/nixmon/nixmon.conf) with btop-style keys:

color_theme = "nord"
update_ms = 1500
proc_sorting = "cpu"
proc_reversed = false
net_iface = "auto"
disk_filter = ""

disk_filter accepts a regex; prefix with ! to exclude matches.

Keyboard Shortcuts

• q, Esc - Quit
• +, = - Increase refresh rate
• -, _ - Decrease refresh rate
• t - Cycle themes
• e - Edit config
• s - Cycle sort key (CPU/MEM/PID/NAME)
• r - Toggle sort order
• f - Clear process filter
• ↑/↓ - Move process selection
• Enter, i - Toggle process details
• k - Kill selected process
• h, ? - Toggle help overlay

Mouse Support

• Scroll wheel - Scroll process list
• Click - Select process

Additional Commands

After installation, several commands are available:

• nixmon - Run the system monitor
• nixmon-themes - Preview available themes
• nixmon-export-json - Export current metrics to JSON
• nixmon-export-csv - Export current metrics to CSV

Implementation

nixmon is implemented entirely in the Nix language, demonstrating advanced Nix programming techniques including:

• Pure functional data processing
• ANSI terminal rendering with Unicode box-drawing characters
• System metrics collection via /proc (Linux) and system commands (macOS)
• State management for delta calculations (CPU usage, network speed, etc.)
• Real-time terminal UI with flicker reduction
• Signal handling for terminal resize events
• Mouse event parsing and handling
• Modular architecture with separate modules for UI, metrics, and platform-specific code

License

MIT