k314159's questions

I've installed the unicode package using apt install unicode on Ubuntu 24.04 LTS:

unicode/noble,noble,now 3.1-1 all [installed]
  display unicode character properties

The help text shows a peculiar option "--brexit-ascii":

  --ascii               Display ASCII table
  --brexit-ascii, --brexit
                        Display ASCII table (EU-UK Trade and Cooperation
                        Agreement version)

What exactly is this "ASCII table (EU-UK Trade and Cooperation Agreement version)"? I couldn't find any technical information about it. Is there actually such a thing or is it some sort of political protest from the developer?

Is there a way to specify a keyboard shortcut to switch to a specific window? I know about Alt+Tab, Alt+`, Alt+Esc etc. But all of those keys cycle through all windows, which is not what I'm looking for. I would like a key that takes me straight to a specific window, irrespective of which window is currently in focus.

My use case is that I use Google Meet for meetings while also looking at other windows (slides, web pages, code editors, Slack). I'm muted most of the time, and when I want to talk, I can press the space bar to temporarily unmute myself ("push-to-talk" feature). But that only works when I'm in the Google Meet window. So what I'm looking for is a key that I press, followed by the space bar, so that I can quickly start talking on Google Meet.

I want to connect via RDP from an Ubuntu 20.04 laptop to an Ubuntu 22.04 desktop.

I've read in the release notes that the 22.04 release support RDP connections. I enabled Remote Desktop sharing in GNOME Settings. However, when I try to connect from my laptop, the Remmina client gets stuck on "Reconnection attempt 1 of 20" (flicking between attempt 0 and 1).

When I look at tutorials on the web for making RDP connections to 22.04, they say we should install xrdp. Is this right? The 22.04 release notes say "RDP is now available for sharing your desktop remotely." If we really have to install an RDP server, what does it mean that "RDP is now available"? How is 22.04 different from previous versions with xrdp installed?

How can I add a terminal application (such as less or python) if that application doesn't appear in the list when I press the "Show Applications" button?

Is it possible to make the task bar appear on both displays in a dual-screen setup, instead of just in the primary display?

What does the setting "Automatically Delete Temporary Files" actually do? Two parts to this question: (1) what is meant by "automatically" ? Every day? Every login session? Every millisecond? (2) What is meant by "temporary files"? Are these the files in the /tmp directory? That seems to be cleaned every time I reboot, in spite of having this option in GNOME's Settings disabled.

When I look at a PDF of an A4 paper (or US Letter-sized paper), and set the zoom scale to 100%, the paper on the screen looks twice the actual width (42 cm instead of 21 cm). This happens with all PDF files. On the other hand, if I look at the file at 100% using Adobe Reader on Windows, it displays at the correct size. In both cases, my screen is HD at about 100 dpi. Why is evince wrong? Is there a setting to correct it?

Both my laptop (Ubuntu 20.04) and desktop (Ubuntu 21.10) have the same issue.

By comparison, Google Chrome displays the same PDF files correctly.

On my laptop:

$ evince --version
GNOME Document Viewer 3.36.10

On my desktop:

$ evince --version
GNOME Document Viewer 40.4

I've seen this question:

How to set visible columns default for the 'Files' file manager?

and would like to ask how to do it now in Ubuntu 21.10 (Files 40.2) because the Preferences dialog no longer has the tabs that previous versions had; i.e. now that the set of columns to use as default is no longer shown as a tab in Preferences, how can we set the default?

I am using the built-in VNC server, which I believe is called gnome-remote-desktop and is enabled using GNOME Settings -> Sharing -> Screen sharing.

I enabled it on my desktop PC and can connect successfully to it from my laptop PC (the idea behind this is to make it easier to use a single keyboard and screen without having to press button to switch between the two).

However, in order to connect to it, I need to be logged in on the desktop PC. Can I run this server as a service so that I can connect to my PC from my laptop and then log in?

(This question is similar to this one from 2015 but this question is about gnome-remote-desktop whereas the other question was about the now-discontinued vino. Also, in the 6 years that have passed, there may be better solutions.)

I have a Canon Pixma MG6450 connected through the wireless network to my Ubuntu 21.04 system. The driver was downloaded from Canon's website. It uses a bash script to install itself.

Printing is very slow, at about 1 page per hour. The same document can be printed from my Windows PC in less than a minute. This delay seems independent of software: it's very slow whether I'm printing a PDF using evince, a diagram created in Gimp, or a bash script printed from gedit.

What steps can I take to diagnose where the bottleneck is?

Using this lz4 command:

$ apt search ^lz4$
Sorting... Done
Full Text Search... Done
lz4/focal,now 1.9.2-2 amd64 [installed,automatic]
  Fast LZ compression algorithm library - tool

$ lz4 --version
*** LZ4 command line interface 64-bits v1.9.2, by Yann Collet ***

This command normally creates a filename.lz4 file (just like gzip does):

$ lz4 -9 -k filename

However, this command does not, and instead writes to stdout when I'm not telling it to:

$ t=$(lz4 -9 -k filename)
Warning : using stdout as default output. Do not rely on this behavior: use explicit `-c` instead ! 
bash: warning: command substitution: ignored null byte in input

Why is it doing this? Is it a bug, or is there a reason documented somewhere?

Until yesterday, my wifi has been running perfectly for as long as I've had this system (many months). Since yesterday, it has been dropping every 20-30 minutes, and reconnecting automatically after about 30 seconds (usually on 2nd attempt).

I've looked at the many existing "wifi keeps disconnecting" questions on this site but none of them has solved my issue.

I've got a desktop with a wifi USB dongle, with very strong signal.

Taking advice from answers to similar questions, I've already disabled power management on wifi and USB, but the issue persists.

When the wifi drops, the command sudo journalctl -fu NetworkManager shows the following line:

NetworkManager[...]: <warn>  [161...] sup-iface[0x...,wlx...]: connection disconnected (reason -14)

Is there a list of Network Manager reason codes from which I can see what -14 means?

I ran a command using Alt+F2 .

I then realised that the command would have output something important to standard output and/or standard error.

Is there a way to display the output of that command? (Is it logged somewhere? Is there a way to get a hidden window that contains the output of all commands launched via Alt+F2? Or is it too late?)

When an application is running, there is a small red dot next to the icon on the GNOME launcher sidebar (Ubuntu Dock). When two instances of the same application are running, there are two small red dots.

When I launch Slack to connect to my employer's workspace, the Slack application launches a Chrome page to authenticate my credentials. When that happens, I see two small red dots against the Slack icon. How do I get it to show me one red dot against Slack and one red dot against Chrome? I know it's possible because this is the behaviour on my other PC, which runs Fedora.