Joular Core ⚡

This is a command line program that uses Joular Core - Rustic library to monitor energy on all platforms and operating systems.

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Screenshots

CLI — Linux, Windows, macOS, Raspberry Pi

Process and application monitoring

Numeric and CSV output modes

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CLI Options

Run joularcore --help for a complete list. The main options are:

Option	Description
-p, --pid <PID>	Monitor a specific process by PID
-a, --app <APP>	Monitor an application by name (covers all its processes)
-f, --file <FILE>	Write output to a file. CSV is used by default; with -i, the file receives numeric-only values.
-o, --overwrite	With -f, truncate before each write so only the latest data row/value is kept
-c, --component <cpu|gpu>	Show only CPU or only GPU power
-i, --numeric	Output only the numeric value, no formatting or labels
-s, --silent	Suppress terminal output (file and ring buffer still work)
-r, --ringbuffer	Write power data to the shared-memory ring buffer
-v, --verbose	Show the library's log records, such as why a sensor could not be read. Repeat for more detail.
--app-match <exact|contains>	How --app matches process names (default: exact)
--elevation <never|sudo>	How far to go for privileged sensor access (default: never)
--app-refresh-interval <SECONDS>	How often to rescan for new PIDs belonging to an application (default: 3s; set to 0 to rescan every second)
--cpu-idle-baseline <WATTS>	Subtract a fixed idle CPU baseline before attributing power to a PID or application
--calibrate-cpu-idle-baseline	Measure idle CPU power automatically (5 samples, 1 second each) and use that as the baseline

Notes:

• --pid and --app are mutually exclusive.
• --cpu-idle-baseline and --calibrate-cpu-idle-baseline are mutually exclusive.
• -o only has effect when used with -f.
• When -f is used, the live terminal display is replaced by file output.
• --app-match defaults to exact, which ignores case and a trailing .exe. Earlier releases matched substrings on Linux and macOS; pass --app-match contains for that behaviour. Exact matching avoids over-matching (code would otherwise also match codesign), but it excludes helper processes such as firefox-bin.
• Power interfaces are privileged on most systems. A sensor that cannot be read shows as n/a rather than 0.00; run with -v to see why. On macOS powermetrics needs root, so either run the whole CLI under sudo, or cache a sudo credential and pass --elevation sudo. Joular Core never prompts for a password itself.
• The GUI is a separate program, joularcoregui.

Examples

# Monitor system power
joularcore

# Monitor a specific process
joularcore -p 1234

# Monitor an application by name, write to CSV
joularcore -a firefox -f power.csv

# Include helper processes such as firefox-bin
joularcore -a firefox --app-match contains

# Run silently and write to CSV
joularcore -s -f power.csv

# Only show CPU power, numeric output
joularcore -c cpu -i

# Subtract idle CPU baseline when attributing process power
joularcore -p 1234 --calibrate-cpu-idle-baseline

# On macOS, after caching a sudo credential with `sudo -v`
joularcore --elevation sudo

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🔨 Building

The CLI uses the published joularcore-rustic library from crates.io, so Cargo fetches it for you:

git clone https://github.com/joular/joularcore-cli-rustic.git
cd joularcore-cli-rustic && cargo build --release

The binary lands at target/release/joularcore. Cargo features: vm (default) reads power from files written by a hypervisor, and sbc builds for single-board computers such as the Raspberry Pi (--no-default-features --features sbc).

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🟢 Systemd service on Linux

A ready-to-use systemd unit file is included in the systemd/ directory. It runs Joular Core CLI as a daemon that continuously overwrites /tmp/joularcore-service.csv with the latest power reading. Because overwrite mode truncates before each write, the default service file contains only the latest data row, without a CSV header.

sudo cp systemd/joularcore.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable joularcore
sudo systemctl start joularcore

To use a different output path or add options, edit the ExecStart line in the service file before copying it.

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📜 License

Joular Core CLI is licensed under the GNU General Public License 3 license only (GPL-3.0-only).

Copyright © 2025-2026, Adel Noureddine. All rights reserved. This program and the accompanying materials are made available under the terms of the GNU General Public License v3.0 (GPL-3.0-only) which accompanies this distribution.

Author: Prof. Adel Noureddine