Cap

A minimal GNOME Shell extension that caps your daily Wi-Fi data usage. Cap tracks traffic via /proc/net/dev, shows live rates in the top bar, and terminates the Wi-Fi interface with nmcli the moment the daily limit is reached.

GNOME Shell 45+ (ESM imports). Tested on GNOME 48.

Install

From extensions.gnome.org

Install from the GNOME Extensions website.

From source

git clone https://github.com/anorak999/Cap.git
cd Cap
./install.sh      # compiles schemas, symlinks, and enables

Restart GNOME Shell to load:

• Wayland — log out and back in.
• X11 — Alt+F2 → r → Enter.

To remove:

./uninstall.sh

How it works

• Telemetry — /proc/net/dev is read once per second. Receive and transmit deltas are summed (rx + tx) and accumulated per wireless interface matching /^wl/.
• Cutoff — when usage exceeds the daily limit, Cap emits a notification and runs nmcli radio wifi off.
• Midnight rollover — usage resets to 0. Wi-Fi stays off; re-enable it from the dropdown or GNOME quick settings.
• Re-enable — raise the limit above current usage, or press the Re-enable Wi-Fi button.

Top bar

Shows ↓ {rx} ↑ {tx} live rates. Turns amber at 90% of the daily limit.

Dropdown styles

Three switchable panel styles in gnome-extensions prefs cap@anorak:

Style	Description
Default	Progress bar, slider, numeric entry.
Orbit	Ring gauge with card-style limit control.
Strata	Flat row-list with inline bar and status pill.

Settings

Key	Type	Default	Notes
daily-limit-mb	i	1024	100 – 50,000 MB
used-bytes	x	0	Resets at midnight
current-date	s	""	Tracked day (YYYY-MM-DD)
popup-style	s	"default"	default, orbit, or strata

Requirements

• GNOME Shell 45+
• nmcli on $PATH (ships with NetworkManager)

License

GPL-3.0-or-later.