I have a systemd timer and service that runs my backup script daily. The
script runs on root privileges.
If the backup script notices an error I would like to report the error
as a notification in normal user's desktop. In the past this worked with
"wall" command in the backup script:
wall "The backup failed. See the journal for more info."
KDE Plasma desktop has a background service which delivers "wall"
messages as desktop notifications. This doesn't work anymore. "wall"
messages doesn't show in desktop even though the background service is
running.
I don't know when it stopped working but my first guess is that some of
those features have not been ported to Wayland yet. I switched from X11
to Wayland a couple of months ago (and it's great; I'm not going back).
I also upgraded from Debian 12 to 13 last summer.
So, the general question is: how could a background root script give a
desktop notification for the current / all users?
--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: DD3B8E8ABD28B98176E6A7CCCC9A5E615FCC1D93
/ old key: 6965F03973F0D4CA22B9410F0F2CAE0E07608462


--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Hello,

wall is now provided by the bsdutils package (priority: required): is it installed?

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-03-02, Teemu Likonen wrote:

I don't know when it stopped working but my first guess is that some of
those features have not been ported to Wayland yet. I switched from X11
to Wayland a couple of months ago (and it's great; I'm not going back).
I also upgraded from Debian 12 to 13 last summer.

You could look at this bug report about wall https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1115259

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

* 2026-03-02 12:38:09+0100, Michel Verdier wrote:

You could look at this bug report about wall https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1115259

That is probably saying that "wall" will not be fixed for the operation.
I'm not fixed to "wall". We can ditch it. The general question is: How
could a background root script give a desktop notification for the
current / all users?
--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: DD3B8E8ABD28B98176E6A7CCCC9A5E615FCC1D93
/ old key: 6965F03973F0D4CA22B9410F0F2CAE0E07608462


--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 02/03/26 at 08:46, Teemu Likonen wrote:

So, the general question is: how could a background root script give a desktop notification for the current / all users?

Have you tried "notify-send"? It is provided by the "fyi" package.

kind regards.
--
Franco Martelli

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 2026-03-02, Teemu Likonen wrote:

I'm not fixed to "wall". We can ditch it. The general question is: How
could a background root script give a desktop notification for the
current / all users?

If you are on a single system you could use xmessage from the package
x11-utils

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

* 2026-03-02 14:29:24+0100, Franco Martelli wrote:

On 02/03/26 at 08:46, Teemu Likonen wrote:

So, the general question is: how could a background root script give
a desktop notification for the current / all users?

Have you tried "notify-send"? It is provided by the "fyi" package.

Not that one (before) but those notification daemons tend to require the
same user. So does "fyi":
$ sudo fyi Title Message
error: failed to connect: /usr/bin/dbus-launch terminated abnormally
without any error message
So root can't easily send notifications for other users.
Maybe I'll make my backup script's error messages go to a specific text
file and write a user's systemd path unit that triggers on changes of
that file. The triggered service would print "fyi" notification with
file's content as the message. Something like that.
But a good operating system should have an easy uniform way for any
maintenance task to inform desktop user. Maybe systemd people will come
up with something some day. They are good at thinking of big picture.
--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: DD3B8E8ABD28B98176E6A7CCCC9A5E615FCC1D93
/ old key: 6965F03973F0D4CA22B9410F0F2CAE0E07608462


--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 02/03/26 at 08:46, Teemu Likonen wrote:

KDE Plasma desktop has a background service which delivers "wall"
messages as desktop notifications. This doesn't work anymore.

Do you refer to "kwrited"? "kwrited" is for X11 maybe you could ask to
KDE guys whether there is something for Wayland.

Kind regards.
--
Franco Martelli

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On 02/03/26 at 16:18, Teemu Likonen wrote:

Not that one (before) but those notification daemons tend to require the
same user. So does "fyi":

$ sudo fyi Title Message
error: failed to connect: /usr/bin/dbus-launch terminated abnormally
without any error message

So root can't easily send notifications for other users.

Yes, but if you want to ditch "wall" then you could try to play with
this code in your script:

uid=1000 gid=1000
setpriv --reuid "$uid" --regid "$gid" --init-groups \
env XDG_RUNTIME_DIR=/run/user/"$uid" DISPLAY=:0 XDG_CURRENT_DESKTOP=KDE
fyi TEST test

Of course you have to change 1000 if your user id is different, the "id" command will tell you which value of uid and gid to use. Also the
DISPLAY value matters. Here it works, but I'm on KDE+X11, not Wayland sorry.

Unlike the "wall" command, you will have to write a "setpriv" command
for each user you want to notify if something goes wrong in the script.

Kind regards.
--
Franco Martelli

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Mon, 2026-03-02 at 09:46 +0200, Teemu Likonen wrote:

So, the general question is: how could a background root script give
a desktop notification for the current / all users?

If no better & more generic solution pops up, you could have the backup
script write its "message" to a file in a specific location, and then
in the desktop user session watch that file for changes, sending its
content to the notify daemon (which can be done with a simple script & 'inotifywait'). For your personal use that might be sufficient,
although a more generic solution would be nice...


--
Jan Claeys

(please don't CC me when replying to the list)

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

* 2026-03-05 16:04:53+0100, Jan Claeys wrote:

On Mon, 2026-03-02 at 09:46 +0200, Teemu Likonen wrote:

So, the general question is: how could a background root script give
a desktop notification for the current / all users?

If no better & more generic solution pops up, you could have the backup script write its "message" to a file in a specific location, and then
in the desktop user session watch that file for changes, [...]

I did that. A systemd .path unit watches for changes in the file and
triggers a .service unit for showing the notification. Simple enough but
indeed there's a need for a good generic solution.
--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: DD3B8E8ABD28B98176E6A7CCCC9A5E615FCC1D93
/ old key: 6965F03973F0D4CA22B9410F0F2CAE0E07608462


--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Thu, Mar 05, 2026 at 07:42:05PM +0200, Teemu Likonen wrote:
[...]

I did that. A systemd .path unit watches for changes in the file and
triggers a .service unit for showing the notification. Simple enough but indeed there's a need for a good generic solution.

Uh-oh. That's what notification in the age of systemd has come to.
Cheers
--
tom s


--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

The ArchWiki (https://wiki.archlinux.org/title/Desktop_notifications#Send_notifications_to_all_graphical_users)
offers this snippet:

# for id in $(loginctl list-sessions -j | jq -r '.[] | .session')ÿ; do
if [[ $(loginctl show-session $id --property=Type) =~ (wayland|x11) ]]ÿ; then
systemd-run --machine=$(loginctl show-session $id --property=Name --value)@.host --user \
notify-send 'Hello world!' 'This is an example notification.'
fi
done

On 02/03/2026 07:46, Teemu Likonen wrote:

I have a systemd timer and service that runs my backup script daily. The script runs on root privileges.

If the backup script notices an error I would like to report the error
as a notification in normal user's desktop. In the past this worked with "wall" command in the backup script:

wall "The backup failed. See the journal for more info."

KDE Plasma desktop has a background service which delivers "wall"
messages as desktop notifications. This doesn't work anymore. "wall"
messages doesn't show in desktop even though the background service is running.

I don't know when it stopped working but my first guess is that some of
those features have not been ported to Wayland yet. I switched from X11
to Wayland a couple of months ago (and it's great; I'm not going back).
I also upgraded from Debian 12 to 13 last summer.

So, the general question is: how could a background root script give a desktop notification for the current / all users?

--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

* 2026-03-05 20:41:00+0000, Darac Marjal wrote:

The ArchWiki (https://wiki.archlinux.org/title/Desktop_notifications#Send_notifications_to_all_graphical_users)
offers this snippet:

# for id in $(loginctl list-sessions -j | jq -r '.[] | .session')ÿ; do
if [[ $(loginctl show-session $id --property=Type) =~ (wayland|x11) ]]ÿ; then
systemd-run --machine=$(loginctl show-session $id --property=Name --value)@.host --user \
notify-send 'Hello world!' 'This is an example notification.'
fi
done

Thank you! I knew that the systemd guys had all the basic pieces
together already. Now they only need to write the final pieces of the
new /usr/bin/wall-for-the-desktop-generation tool. I wrote my own in the
Fish shell:
#!/usr/bin/fish
set notify_program /usr/bin/fyi
set notify_args $argv
for session in (loginctl list-sessions --no-legend | cut -d' ' -f1)
set -l type (loginctl show-session $session -p Type --value)
if string match -qr '^(wayland|X11)$' $type
set -l user (loginctl show-session $session -p Name --value)
systemd-run --user -M $user@ -- $notify_program $notify_args
end
end
(Fish shell does not have sh-like word splitting so similar quoting is
not needed.)
--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: DD3B8E8ABD28B98176E6A7CCCC9A5E615FCC1D93
/ old key: 6965F03973F0D4CA22B9410F0F2CAE0E07608462


--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

On Thu, 2026-03-05 at 20:41 +0000, Darac Marjal wrote:

if [[ $(loginctl show-session $id --property=Type) =~ (wayland|

x11) ]]; then

Why the check for wayland/X11 ?

Better to just try to send a notification and let it fail for sessions
that don't support it rather than sending nothing to a session that is
not wayland or X11 but still supports notifications. (I'm sure not all X11/wayland sessions support it either...)


--
Jan Claeys

(please don't CC me when replying to the list)

--- PyGate Linux v1.5.13
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)