System Monitor

A terminal and web system monitor written in Sun.

Install

The installer supports Linux x86_64/ARM64 and Apple Silicon macOS. Run it as yourself to install under ~/.local for your user only, or with sudo to install under /usr/local for all users:

curl -fsSL https://raw.githubusercontent.com/namo-robotics/system_monitor/main/scripts/install.sh | bash

curl -fsSL https://raw.githubusercontent.com/namo-robotics/system_monitor/main/scripts/install.sh | sudo bash

PREFIX overrides the install root. To build from source instead, see Build and run.

Uninstall

The same script removes everything it installed in that scope, including the daemon if one was set up. Run it as yourself or with sudo to match the install:

curl -fsSL https://raw.githubusercontent.com/namo-robotics/system_monitor/main/scripts/install.sh | bash -s -- --uninstall

Run as a daemon

On Linux x86_64, where the web dashboard is built, the installer asks whether to also run the dashboard as a systemd service, and on which loopback port (default 29583). The default answer is no, and without a terminal it never asks. A user install starts the service with your login session; a sudo install starts it at boot under an unprivileged dynamic account. Either way the dashboard listens only on 127.0.0.1, so use SSH port forwarding for remote access.

For unattended installs, DAEMON=0|1 and PORT answer the questions ahead of time:

curl -fsSL https://raw.githubusercontent.com/namo-robotics/system_monitor/main/scripts/install.sh | DAEMON=1 PORT=29583 bash

A per-user service stops when you log out unless you run loginctl enable-linger "$USER" once.

Usage

Start system_monitor to open Processes, with horizontal tabs for all five monitors in the same terminal window. Press 1–5 to switch directly and q to quit.

Key	Monitor	Shows
1	Process	CPU, resident memory, process history, ROS 2 labels and process controls
2	Disk	Mounted filesystems, total/used/available space and capacity percentage
3	Service	Loaded systemd services, including inactive and failed units; launchd jobs on macOS
4	Network	Linux interface state, receive/send rates and totals, errors and drops
5	Temperature	Linux hwmon sensors, Celsius temperatures and critical thresholds; thermal-zone fallback

Use Up/Down to select or scroll rows. Up from the first row focuses the tab bar; Left/Right switches tabs, and Down/Enter returns to the view. Tab toggles focus between tabs and content; b also focuses the tabs. The focused tab is highlighted yellow. Number shortcuts work from either area, including while paused. Tabs use shorter labels in narrow terminals.

Space pauses the display while collection continues. Long rows are clipped to the terminal width; widen the terminal to see more. Process controls are c/m to sort, f/0/a for top 5/10/all, t/k to terminate/kill, and ? for help. The top-five shortcut is now f, because 5 selects Temperature. Process actions are available only while the process table has focus.

Each resource terminal tab uses a bordered table and a dotted history graph:

Tab	Terminal graph
Disk	Used capacity percentage for the selected filesystem
Service	Active and failed service counts
Network	Receive/send KiB/s for the selected interface
Temperature	Selected sensor temperature and its critical threshold

Use Up/Down to choose the row to chart. Graphs collect while that tab is open, including while the display is paused. History survives tab switches; missing measurements and sampling gaps stay blank. --graph-window sets the time span. Resource charts share one quarter of the interactive --memory-limit budget; process history uses the remainder. Resource history is also capped at 2,048 frames and is not included in process recordings. The styled views need at least 65 columns and 18 rows. Unsupported collectors show availability details.

Build and run

Use a current Sun compiler. On Linux x86_64:

scripts/ci-toolchain.sh
bash scripts/setup-musl.sh
scripts/build.sh
build/system_monitor

The build script prefers .ci/toolchain/bin/sun, then falls back to sun on PATH. Set SUN_BIN to override the compiler explicitly.

Or select a view directly:

build/system_monitor --monitor disk
build/system_monitor --monitor service
build/system_monitor --monitor network --interval 0.5
build/system_monitor --monitor temperature --samples 1
build/system_monitor --monitor process --top 5 --sort cpu
build/system_monitor --monitor process --record session.jsonl
build/system_monitor --replay session.jsonl

Redirected input/output defaults to the process view for compatibility with scripts. Use --monitor NAME --samples N for finite resource snapshots without terminal escape sequences. Network rates display N/A on the first sample, when an interface appears, or after a counter reset.

The web dashboard is available on Linux x86_64, with horizontal tabs for all five monitors. It opens on Processes; select another tab to switch views:

build/system_monitor --ui both  # http://127.0.0.1:29583

The tabs are Processes, Disks, Services, Network, and Temperature. Direct links such as http://127.0.0.1:29583/#network open a specific tab. Each browser selects its own view independently of the terminal. The four resource tabs show live host data, including when process recordings are being replayed. Pause affects only the display; data collection continues. Recording/replay and labels apply to process data. With web hosting enabled, process collection continues even when another terminal monitor is selected.

Each tab includes a table and a visualization:

Monitor	Visualization
Processes	CPU or memory history for the top five processes
Disks	Usage bars for the fullest filesystems
Services	Service counts grouped by active state
Network	Receive/send traffic history, with an interface selector
Temperature	Sensor readings with reported critical-threshold markers

The four resource tables support filtering and sorting by column. Missing measurements show N/A; charts never substitute zero for unavailable readings. Network history covers the last minute observed by the browser and continues collecting while another tab is selected.

Platforms and data sources

• Linux x86_64 / ARM64: process data from procfs, disk capacity via df, services via systemctl, network data from procfs/sysfs, temperatures from sysfs.
• Apple Silicon macOS: process support, disk capacity via df, current-domain launchd jobs via launchctl, and network totals via netstat. Network rates and temperature sensors are currently Linux-only.
• Missing utilities, service managers, permissions or sensors produce an unavailable message. Monitoring does not require root. Service monitoring is read-only and lists loaded services, not every installed unit file.

The new views have been exercised on Linux x86_64. Native ARM64 and macOS validation runs in the CI matrix; it has not been performed locally.

Tests

SUN_BIN="$PWD/.ci/toolchain/bin/sun" scripts/test.sh

Includes collector calculations, CLI validation, all five terminal tabs, arrow navigation and focus, and the process, recording, terminal and HTTP checks.

The dashboard DOM tests cover tables, charts, filtering, sorting, missing data, and bounded network history. They require Node.js and the test-only jsdom package; the dashboard itself has no external dependencies:

npm install --prefix /tmp/system-monitor-dom jsdom@29.1.1
NODE_PATH=/tmp/system-monitor-dom/node_modules node tests/dashboard.cjs

Build and usage details. Distributed under the MIT license.