A Gnome Shell Extension for NUT (Network UPS Tools)
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What is it?

walNUT is nothing more than a Gnome Shell extension providing a graphical interface to NUT (Network UPS Tools). It provides you a handy panel menu and icon to monitor your devices and execute NUT’s instant commands.

Before you start, you need an already up and running NUT on the machine that will monitor the UPSes (it’s not necessary to have NUT installed on the same computer you want walNUT to run in, provided that it isn’t the one that’s in charge of communicating with the UPS): having said that, if everything goes well with upsc, upsrw and upscmd, chances are high that walNUT will work right out of the box.


Since the GJS implementation of NUT’s net protocol doesn’t support yet TLS, if you need it, you can get it using the walNUT version that relies on upsc, upsrw and upscmd:

1. Installation

You can install this extension for your user by executing:

cd ~/.local/share/gnome-shell/extensions
git clone --depth 1 https://github.com/zykh/walNUT.git walnut@networkupstools
glib-compile-schemas walnut@networkupstools/schemas/

After the installation you’ll need to restart Gnome Shell:

  • ALT+F2 to open the command prompt

  • Enter r to restart Gnome Shell

Then you can enable the extension through Gnome Tweak Tool (Shell Extensions → walNUT → On) or through https://extensions.gnome.org/local/


Users of previous versions of walNUT, when upgrading, must always recompile the schema:

cd ~/.local/share/gnome-shell/extensions/walnut@networkupstools
git fetch
git merge
glib-compile-schemas schemas/

2. First execution

Once you’ve installed walNUT, when it’s executed for the first time, or every time its device list is empty, it’ll try and search automatically for new devices at localhost:3493.
So, for most installations, it should have already found your devices. If not, you have to add them through the find new devices box.

It’s important that you understand how walNUT communicates with you and how you can customize it: please read panel icon/label, panel menu and preferences sections.

3. Panel icon/label

walNUT's icon and label are customizable through the preferences.
Here is explained how they behave.

Panel Icon

The panel icon standardly displays only battery charge [A], but it can display also device load [B], if available.
In that case the ‘seed’ of the walnut will be split up in two pieces: the leftmost [1] will display battery charge, the rightmost [2] load level.

In case you set also to Display load in panel icon in the preferences and battery charge is not available, the left side of the ‘seed’ [3] will be full and transparent.

Panel Icon - Online/On Battery + Charged/Charging

The panel icon displays also the state of the line: if the device is on line (mains is not absent, ups.status: OL) there will be a small lightning [C] at the right of the nut that wont be displayed if the device is on battery [D].
That lightning will show also if the device is charged or not: if battery charge is 100% or if battery charge is not available and the device isn’t telling us it’s charging or discharging (ups.status: CHRG/DISCHRG) we’ll assume it’s charged and the lightning will be transparent [E], otherwise it’ll be at full opacity [F].

Panel Icon - Caution

For other status (ups.status: BYPASS, TRIM, ..) or if an alarm arises (ups.status: ALARM + ups.alarm) there will be an exclamation mark on the right top angle of the nut.

Panel Icon - Ghost

If battery charge is not available or if also Display load in panel icon option is selected in the preferences and both device load and battery charge aren’t available the icon will be a full transparent nut.

Panel Icon - Error

That’s the icon displayed in case of errors.

Panel Labels

walNUT can also display a label, at the right of the icon in the panel, with battery charge [G], device load [H] or both [I], if available.


The icon shows charge/load through 3 bars:

Icon Bars Meaning

3 bars for charge/load

3 bars

More than 75%

2 bars for charge/load

2 bars

Between 50% and 75%

1 bar for charge/load

1 bar

Between 25% and 50%

No bars for charge/load

no bars

Less than 25%

4. Panel menu

Here’s a quick overview of the panel menu.
Standardly the menu looks like this:

Panel Menu

With all the available options set:

Panel Menu - Complete

The menu can be split up in various sections:

In case of errors, the menu appears like this:

Panel Menu - Error

Where the device list [A] is visible or not, depending on the type of error [L].

4.1. Device list

Device List

Devices are listed in hostname:port alphabetical order and then alphabetically by their name.

Every device stored in walNUT's own list will be prompted for availability every time you change some option or Gnome Shell is refreshed (e.g. return from screen block ..and so on) or 15 minutes after the last update.
Device List opened

Not available devices are signaled with a (N/A) [A] at their right. You can choose either to display or not not available devices in the preferences.

4.2. Device model

Device Model

If available both device manufacturer and device model will be shown here.

If your device isn’t providing one of device manufacturer/model or both or if you want a more appealing label, you can override one of them or both in ups.conf.

You can choose whether to display or not this information changing its option in the preferences.

4.3. Device status

Device Status

Device status will show: line status [A] (online/on battery), and then, on the second row, every status reported by the device [B] (bypass, trim, ..).

4.4. Device alarm

Device Alarm

If an alarm is set (ups.status: ALARM and ups.alarm) it’ll be shown here.

An alarm will be signaled also through an ‘exclamation mark’ on the panel icon.

4.5. Data table

Data Table

If available, [A] battery charge, [B] device load, [C] backup time and [D] device temperature will be shown here.
Battery icon [1] will display actual charge through the number of horizontal bars (as the ones of panel icon).

You can choose whether to display or not these data changing their options in the preferences.

4.6. Raw vars

Raw Vars

If you want a deep dive in all the variables available for a device you have to select the Display raw data option in the preferences: raw vars will be displayed in a scrollable submenu.

If a variable is settable, a + will be shown at the left of its name: clicking on this var will open a new box where you’ll be able to change its value.

Settable vars

Clicking again on the variable will close the box: the changes done won’t be discarded so that you can go back and edit the var starting from where you left.

In order to set a variable you have to provide a valid username and password (as set in upsd.user configuration file).

If the variable is of type ‘STRING’ you can insert a value in the text box [A]: if you then click on the ‘Set’ button [B] the provided value will be sent to the driver. If you click on the ‘Undo and close’ button [C] the provided value will be discarded and the box closed.

Settable vars - STRING

In case the provided value is longer than the acceptable length, you’ll be notified of the error and you won’t be able to click on the ‘Set’ button [B].

Settable vars - STRING, error

If the variable is of type ‘ENUM’, the enumerated values will be listed in the box: if you click on one of them [D] the corresponding value will be sent to the driver. Also the actually chosen option will be shown, but it won’t be clickable [E].

Settable vars - ENUM

If the variable is of type ‘RANGE’, the available ranges will be shown in the box and you’ll then be able to choose the one you need to use.

Settable vars - RANGE, more than one

Once a range is chosen (provided that more than one range is available) [F], its limits [G, H] will be displayed at the right and left of the actual value [I].

Settable vars - RANGE, edit

You can then change the value either dragging the slider [J], or scrolling the mouse wheel over it or you can choose to increase or decrease the value by one unit at a time clicking on the -/+ buttons [K, L].

Settable vars - RANGE, buttons

If you click on the ‘Set’ button [M] the provided value will be sent to the driver. If you click on the ‘Undo and close’ button [N] the provided value will be discarded and the box closed.

In case only one range is available, only its limits will be shown.

Settable vars - RANGE

4.7. Device commands

Device Commands

If you want to execute NUT’s instant commands through walNUT you have to set the Display device commands option in the preferences.

You can also pass to the command some extra data filling, before you click on the command, the entry [A] that will appear next to the device commands submenu when it is opened.

Device Commands - Extra data

Note that, when you click on a command, it’ll be executed.


walNUT standardly displays also a localized description of the commands [B], but if you think that it steals too much space you can set not to display it [C] in the preferences.

Device Commands - Sub Menu, with or w/o description

Once a command has been executed, you’ll be notified whether it has been successfully sent to the driver [D] or not [E].

Device Commands - Notify

4.8. Control buttons

Control Buttons

At the bottom of the panel menu there’s a handful of control buttons, some of which will open their own box [A] just before the controls row [B].

Control Buttons + Control Box

The buttons will show:

4.9. Credentials box

Credentials Box

Clicking on the ‘credentials’ button [A] the credentials box [B] will open. This box is used to store username and password for devices so that you don’t have to be prompted for them every time you execute a command.

If you want to delete username, password or both (e.g. so that you will be prompted for them from now on), you have to save them empty.

If you click on the [1] ‘undo and close’ button any change you made to user/password before clicking on [2] ‘save’ button will be discarded.

Standardly the password is hidden, but if you want, you can choose not to hide it in the preferences.

4.10. Find new devices/find new devices box

Find new devices Box

In order to find new devices, once you clicked on the [A] ‘find’ button, you have to insert the devices' hostname [1] and port [2] and then click on the [B] ‘start search’ button.

If the hostname isn’t given it’ll be localhost, while port, if not given, will fall back to 3493.

You will be notified either if new devices are found [C] or not [D].

Find new devices - Notify

4.11. Delete devices/delete devices box

Delete device Box

If you want to delete a device, first you have to select it from the device list, and then you have to click on the [A] ‘delete’ button.
A new box [B] will appear asking you if you really want to delete it [1] or not [2].

If you want to delete a device that’s not currently available, check first to have enabled the Display not available devices option in the preferences.

5. Device credentials

If you want to execute a device’s instant commands or to set a settable variable, you have to provide a valid username and password (as set in upsd.user configuration file). You can either save them through the credentials box or insert them in the credentials dialog every time you execute a command.

If the saved user and password prove to be wrong you will be prompted for them with a credential dialog when you try to execute a command.
If you choose to save the user and password and then use them for both instant commands and settable vars, be sure that the provided username has the appropriate options set for both of them in upsd.user configuration file (e.g. actions = set and instcmds = all).

5.1. Credentials dialog

Credentials dialog

The credentials dialog will prompt you to insert a valid username or password either if they’ve not been saved through the credentials box or if they proved to be wrong [A].

Credentials dialog - error
The [B] ‘execute’ button will be sensitive only if both username and password are not empty.
Once you have inserted the username and the password, when you click on the [B] ‘execute’ button, the command will be sent to the driver.

6. Preferences

To fine tune walNUT to suit your needs you may want to change some options.

Preferences Button

You can access the preferences from the [A] preferences button in the panel menu.

A new window will open, where you can set the various options.

Preferences - General/Panel

General/Panel tab - extension general options and panel icon/label options:

Available Options
# Option Description

General options


Seconds before next update

The seconds after walNUT updates the data from the device. (default: 15)


Temperature unit

The unit (Centigrade or Fahrenheit) walNUT should display the temperature in. (default: Centigrade)

Panel options


Display load in the icon

Whether the device load should be displayed in the panel icon or not. (default: OFF)


Display load in the label

Whether the device load should be displayed in the panel label or not. (default: OFF)


Display charge in the label

Whether the battery charge should be displayed in the panel label or not. (default: OFF)

Preferences - Menu

Menu tab - panel menu options:

Available Options
# Option Description


Display not available devices

Display also not available devices in the submenu in the panel menu (chosen device will be always displayed, also if not available, in spite of this option). (default: OFF)


Display device model

Show also device model (‘manufacturer - model’), if available, in the panel menu. (default: ON)


Display battery charge

Show also battery charge, if available, in the panel menu. (default: ON)


Display load level

Show also load level, if available, in the panel menu. (default: ON)


Display backup time

Show also backup time, if available, in the panel menu. (default: ON)


Display device temperature

Show also device temperature, if available, in the panel menu. (default: ON)


Display raw data

Show also raw data in a submenu. (default: OFF)


Display device commands

Display available device commands. You’ll need upsd user and password to execute them. (default: OFF)


Display description of device commands

Display also a localized description of available device commands in the submenu. (default: ON)


Hide password at credentials box

Whether the password at credentials box should be hidden or not. (default: ON)

7. Help

If this manual doesn’t answer your questions or for every problem you may encounter, you can find some help at NUT’s list:

If you want to help, you are welcomed in NUT’s list and NUT’s developers list:

7.1. Translators

A guide to translate extensions can be found in Gnome Shell extensions' FAQ.

walNUT's documentation is done in AsciiDoc and then processed either to the html version and to the Mallard version for Yelp.

The help files must be put in the extension’s help subdir, creating a directory named after the desired locale’s language code (e.g. en, it, ..) or, for country-specific locales, language code and country code (e.g. pt_BR, pt_PT).

The html version must be compiled with:

asciidoc --backend=xhtml11 \
	 -a lang=XX \
	 --out-file help.html \

Where help.html is the name the help file must have, manual.txt is the name of your source file and XX is the desired locale’s language code (e.g. it, es, ..).

While the Mallard version needs some further steps:

  1. Download this Mallard backend for AsciiDoc (documentation here)

  2. Install the backend

    asciidoc --backend install mallard.zip
  3. Compile your source file (e.g. manual.txt) with:

    asciidoc --backend=mallard \
    	 -a chunked=1 \
    	 -a toc \
    	 --out-file temp.page \
  4. Download chunkenizer bash script (documentation here)

  5. Give chunkenizer bash script executable permissions:

    chmod +x chunkenizer
  6. Process the previously created temp file temp.page with it:

    ./chunkenizer --yelp temp.page outdir

    Where outdir is the output directory named after your locale (e.g. pt_BR).


If you want to use english manual’s images you have to make a symbolic link to their directory in your locale dir:

ln -s ../C/img img

8. Author

Daniele Pezzini <hyouko@gmail.com>