Prevent applications from increasing output volume in PulseAudio

By default, PulseAudio allows an application to change the max volume output to be louder than the one set by the user. I find it annoying that some apps tend to set volume to 100% which ends up increasing the system volume to unreasonable levels. You can prevent it by setting flat-volumes to no in ~/.config/pulse/daemon.conf.

$ echo "flat-volumes = no" >> ~/.config/pulse/daemon.conf 
$ pulseaudio --kill
$ pulseaudio --start

With flat-volumes = no PulseAudio uses relative volumes. Each applications sets its own volume relative to the system output.

References:

`xdg-open` fails when using Firefox under Wayland

Recently I noticed xdg-open started failing opening links in Firefox. Giving me the following error:

Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.

Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.

It happened while I had Firefox running and responding to everything else. I’m running the latest stable Firefox (74 as I’m writing this) on Wayland. Wayland brings a lot of good things, but also a lot of interoperability problems, so I suspected it had something to do with it. Thanks to Martin Stransky I found out that the solution is to set the MOZ_DBUS_REMOTE environment variable prior to launching Firefox. If you are using a desktop file to launch Firefox, you can set the variable in the Exec line like this:

[Desktop Entry]
Type=Application
Name=Firefox
Exec=env MOZ_DBUS_REMOTE=1 MOZ_ENABLE_WAYLAND=1 /home/guyru/.local/firefox/firefox %u
X-MultipleArgs=false
Icon=firefox-esr
Categories=Network;WebBrowser;
Terminal=false
MimeType=text/html;text/xml;application/xhtml+xml;application/xml;application/vnd.mozilla.xul+xml;application/rss+xml;application/rdf+xml;image/gif;image/jpeg;image/png;x-scheme-handler/http;x-scheme-handler/https;

You will need to restart Firefox before the fix will take affect.

Install JetBrains Mono in Debian/Ubuntu

JetBrains Mono is a new monospace typeface designed to be comfortable to read. It has clear distinction between the different letters and relatively high x-height.

The installation instruction were tested on Debian, but should work on every Linux.

Download and unzip the font:

$ wget https://download.jetbrains.com/fonts/JetBrainsMono-1.0.0.zip
$ unzip JetBrainsMono-1.0.0.zip

Install the font to either the user’s font directory

$ mv JetBrainsMono-*.ttf ~/.local/share/fonts/

or the system-wide one:

$ sudo mv JetBrainsMono-*.ttf /usr/share/fonts/

To use the font in gVim set guifont accordingly in ~/.vimrc:

:set guifont=JetBrains\ Mono\ 13

libGL error: unable to load driver: radeonsi_dri.so

After playing with installing and removing the amdgpu and amdgpu-pro drivers, my system could not load the radeonsi. glxinfo returned the following error:

$ DRI_PRIME=1 glxinfo | grep OpenGL
libGL error: unable to load driver: radeonsi_dri.so
libGL error: driver pointer missing
libGL error: failed to load driver: radeonsi

It was solved by cleaning up leftover symlinks and reinstalling libgl-mesa-dri

$ sudo find /usr/lib/ -lname "/opt/amdgpu/*" -print -delete
/usr/lib/i386-linux-gnu/dri/kms_swrast_dri.so
/usr/lib/i386-linux-gnu/dri/r600_dri.so
/usr/lib/i386-linux-gnu/dri/r200_dri.so
/usr/lib/i386-linux-gnu/dri/vmwgfx_dri.so
/usr/lib/i386-linux-gnu/dri/swrast_dri.so
/usr/lib/i386-linux-gnu/dri/radeonsi_dri.so
/usr/lib/i386-linux-gnu/dri/r300_dri.so
/usr/lib/x86_64-linux-gnu/dri/kms_swrast_dri.so
/usr/lib/x86_64-linux-gnu/dri/r600_dri.so
/usr/lib/x86_64-linux-gnu/dri/r200_dri.so
/usr/lib/x86_64-linux-gnu/dri/vmwgfx_dri.so
/usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
/usr/lib/x86_64-linux-gnu/dri/radeonsi_dri.so
/usr/lib/x86_64-linux-gnu/dri/r300_dri.so

$ sudo apt install --reinstall libgl1-mesa-dri

Yubikey doesn’t work on Firefox installed via Snap

Installing Firefox via Snap is an easy way to get the latest Firefox version on your favorite distro, regardless of the version the distro ships with. However, due to Snap’s security model, Yubikeys, or any other FIDO tokens do not work out of the box. To enable U2F devices, like Yubikeys, you need to give the Firefox package the necessary permissions manually:

$ snap connect firefox:u2f-devices

Generating secure passphrases on the command line

The following snippet should work on every system that has coreutils.

$ shuf /usr/share/dict/words --repeat --random-source /dev/random -n 5

You can swap /usr/share/dict/words with any good wordlist, like EFF’s or Arnold Reinhold’s Diceware list.

You can also add it for ease of use to your ~/.bash_aliases

alias passphrase="shuf ~/dotfiles/misc/diceware8k.txt --repeat --random-source /dev/random -n"

And then you could easily use it in bash:

$ passphrase 5
notch
kane
to
drag
cater

Disable Yubikey’s OTP

By default, when you touch a Yubikey it types an OTP code. These codes looks like:

cccjgjgkhcbbirdrfdnlnghhfgrtnnlgedjlftrbdeut

Theoretically they are used for Yubico’s proprietry authentication, but in reality they are mostly annoying. This is especially true for Yubikey Nano, which is impossible to remove without touching it and triggering the OTP.

Yubikey 5 Nano

Disabling the OTP is possible using the Yubikey Manager, and does not affect any other functionality of the Yubikey.

$ sudo apt install yubikey-manager
$ ykman config usb --disable otp
Disable OTP.
Configure USB interface? [y/N]: y

Note for Yubikey 4: the above command will not work and fail withe the following error:

Error: Configuring applications is not supported on this YubiKey. Use the `mode` command to configure USB interfaces.

Instead use the following command:

$ ykman mode FIDO+CCID
Set mode of YubiKey to FIDO+CCID? [y/N]: y
Mode set! You must remove and re-insert your YubiKey for this change to take effect.

virt-manager: Error starting domain

Virtual Machine Manager (virt-manager) doesn’t automatically start your virtual networks. This leads to the following error when starting a vitual machine

Error starting domain: Requested operation is not valid: network 'default' is not active

To solve this error, on Virtual Machine Manger go to Edit->Connection Details->Virtual Networks, select the required network (‘default’ in our case) and press the Start Network button (has a play-button icon). You can avoid having to go through this process by ticking the Autostart checkbox, which will make the network start automatically at boot.