Cable Labelmaker

A small local app for designing and printing wraparound cable labels on 24 mm Brother laminated tape. It renders a print-accurate preview and sends labels directly to a Brother PT-D600 over USB.

What it does

• Repeats compact, rotated text around the cable for visibility from several sides.
• Supports one, two, or three stacked lines with a consistent 20-dot type size.
• Previews the full 24 mm tape, including the printer's unprintable margins.
• Prints one label or a batch directly over USB.
• Runs locally by default and can optionally be exposed inside a Tailscale tailnet.
• Supports Apple silicon macOS and x86_64/arm64 Linux.

The default label is 48 mm long. This leaves enough overlap for a durable wrap on typical network cables.

Install a release

Download the archive for your platform from the latest GitHub release, extract it, and run the included installer from the extracted directory:

# macOS
scripts/install-macos-service.sh

# Linux
scripts/install-linux-service.sh

Each archive is self-contained. The installer exposes cablelabel at ~/.local/bin/cablelabel and starts the local web app at http://127.0.0.1:9462/. The macOS app is locally signed but not notarized, so the first launch can require Control-click, Open, and confirmation.

Build and install on macOS

Requirements:

• Apple silicon Mac
• uv
• ImageMagick (brew install imagemagick)
• Brother PT-D600 connected over USB

scripts/build-mac-app.sh
scripts/install-macos-service.sh

The installer copies the app to /Applications/Cable Labelmaker.app, installs a LaunchAgent, exposes the CLI at ~/.local/bin/cablelabel, and keeps the web app available at http://127.0.0.1:9462/. The app is locally signed but not notarized. macOS can require one Control-click, Open, and confirmation on first launch.

Build and install on Linux

Linux bundles support x86_64 and arm64. Persistent installation uses a systemd user service. The installer also adds a udev rule for PT-D600 USB access.

Debian and Ubuntu build requirements:

sudo apt install curl file libudev-dev pkg-config shellcheck

Install uv, then build and install:

scripts/build-linux-app.sh
scripts/install-linux-service.sh

The arm64 build also requires a Rust toolchain because ptouch-rs does not publish a Linux arm64 binary. The build compiles its pinned v0.5.0 source. Linux bundles include a pinned Roboto Condensed Bold font and its Apache 2.0 license, so previews and prints do not depend on system-installed fonts.

The installer places versioned bundles under ~/.local/opt/cablelabel, exposes the CLI at ~/.local/bin/cablelabel, enables cablelabel.service, and checks http://127.0.0.1:9462/ before reporting success. It installs the PT-D600 udev rule with the service user as its stable device owner, while retaining desktop-session access. It uses sudo only to install and reload that rule.

For a headless machine that must start the user service before login, enable lingering once:

loginctl enable-linger "$USER"

Use --port PORT with either installer to select another local port. Quit any other program using the PT-D600 before printing because only one process can own the USB device.

Make labels

Put one cable on each row. Use |, ->, →, ↔, or <-> to split a label into as many as three stacked lines:

AT&T UPLINK
ROUTER P3 | FLEX P9 | 2.5G
OFFICE -> SWITCH 08

Clean the cable, wrap firmly, and overlap at least 12 mm of tape onto itself.

Command line

The installer provides the same cablelabel command on macOS and Linux. If ~/.local/bin is not already on your PATH, add it in your shell profile:

export PATH="$HOME/.local/bin:$PATH"

Check the connected printer and make a preview without using tape:

cablelabel status
cablelabel preview "AT&T UPLINK" --output att-uplink.png

Printing is an explicit command. Multiple arguments form a batch, --copies repeats each label, and --stdin reads one label per nonblank line:

cablelabel print "AT&T UPLINK" "COMCAST UPLINK"
printf '%s\n' "ROUTER | PORT 3" "SWITCH | PORT 9" | cablelabel print --stdin

Quote labels containing spaces, |, or other shell metacharacters. Use --length MM on preview or print to select a 39–70 mm wrap length. Run cablelabel serve --help for web-server options.

For agents

Install from an extracted GitHub release exactly as a human would:

# macOS
scripts/install-macos-service.sh

# Linux
scripts/install-linux-service.sh

When working from a source checkout instead, build first with scripts/build-mac-app.sh or scripts/build-linux-app.sh.

For source-tree automation without installing, replace cablelabel in the examples below with:

uv run --with-requirements requirements.txt python main.py

Pass global --json before the subcommand. Successful and failed commands emit one JSON object on stdout, making it safe to parse without scraping prose:

cablelabel --json status
cablelabel --json preview "ROUTER | PORT 3" --output /tmp/router-p3.png
cablelabel --json print "AT&T UPLINK"
printf '%s\n' "ONE" "TWO | PORT 2" | cablelabel --json print --stdin

Only the print subcommand produces physical output. status, preview, --help, and --version never print a label. Do not invoke print merely to test connectivity; use status and inspect a preview PNG first.

Exit codes are stable automation contracts:

Code	Meaning
0	Success
1	Unexpected internal failure
2	Invalid arguments, label text, length, or output path
3	Printer unavailable or failure before any label printed
4	Partial batch: at least one label printed before failure

On a partial batch, the JSON object includes printed, total, zero-based failed_index, and failed_label. An agent should not blindly retry the whole batch because doing so would duplicate labels that already printed.

Printer failures also include a stable reason and retryable boolean. Reasons are busy, not_found, access_denied, timeout, engine_unavailable, and command_failed. Use these fields for control flow and keep error for humans.

The long-running server can also be launched deterministically:

cablelabel --json serve --port 9462 --no-browser

It emits its startup JSON object before serving. Stop it with SIGINT or SIGTERM; do not infer readiness from process existence when an HTTP health check against the emitted url is available.

Tests and temporary automation can pass --port 0. The operating system then selects a free port, which is reported in the startup JSON.

Tailnet access

Cable Labelmaker binds only to localhost. Tailscale Serve can add HTTPS inside your tailnet without opening the app to the public internet.

Replace the example hostname with the machine's Tailscale DNS name:

scripts/install-linux-service.sh \
  --trusted-origin "https://label-host.example.ts.net:9462"
tailscale serve --bg --https=9462 http://127.0.0.1:9462

Use scripts/install-macos-service.sh on macOS. Then open the trusted HTTPS URL. You can repeat --trusted-origin when more than one origin is needed.

Do not use Tailscale Funnel. Cable Labelmaker has no application-level login; tailnet identity and access controls are its remote security boundary.

Development

Run the platform-specific gate used by CI:

make check

Runtime configuration:

Variable	Default	Purpose
CABLELABEL_PORT	9462	Local listening port
CABLELABEL_TRUSTED_ORIGINS	empty	Comma-separated HTTPS origins allowed through a trusted reverse proxy
CABLELABEL_OPEN_BROWSER	1	Set to 0 for a headless service

Direct-print engine

vowstar/ptouch-rs provides USB transport. Builds pin version 0.5.0, verify downloaded SHA-256 digests, and bundle its GPL license. The Linux arm64 bundle compiles the same pinned source with Cargo's lockfile. See THIRD_PARTY_NOTICES.md.

License

The original Cable Labelmaker source is available under the MIT License.