I want an easy way to run one or more ephermal Linux VMs in Ubuntu desktop, including the possibility to mount host directories into them in an efficient fashion. Those VMs should have the same CPU architecture and hardware features as the host, no need to emulate some foreign CPU or special hardware, and no GUI in the VMs. The intended use case is sandboxing and isolation for security and reproducability reason. To be used as a cheaper alternative to a remote cloud instance. Or as a more secure alternative to Docker/Podman containers, with possibility to install Docker or Podman in the VM, and run containers there without affecting the host or other VMs (it’s not feasible to nest containers in a secure manner without a proper VM).

You can do quite a lot with Docker, but sometimes you want greater capabilities or increased security, then a proper virtual machine with KVM is a good alternative. An example is when you want to run Docker containers in the VM, it’s not easy to nest Docker without forgoing all security.

Just like Alpine Linux is suitable as a base for Docker images, it is also a good option as a guest in a virtual machine.

As I have explained earlier, I am using Leafpad instead of gedit in my Ubuntu system.

However, recent versions of Ubuntu does not have Leafpad available through APT any longer, you have to install it with Snap instead. This is quite annoying, since the Snap packaging of Leafpad is too restrictive, it cannot access hidden files in your home directory, nor anything in ~/bin/. This is not good, since I often want to use Leafpad to edit such files.

Docker’s official documentation on how to enable multi-platform Docker builds is a bit intimidating, suggesting you to run the Docker image tonistiigi/binfmt in privileged mode on your machine. I searched for alternatives on Ubuntu, and found this very detailed description. However, with recent versions of Ubuntu and Docker, it is now much easier than that:

1. Install QEMU’s static user mode emulation binaries:
   sudo apt install qemu-user-static
2. Install Docker Engine with Buildx support according instructions here (do not install docker-ce or docker.io from Ubuntu’s standard repository).
3. Create a Docker Buildx builder:
   docker buildx create --name multiplatform --bootstrap --use
4. Verify it:
   docker buildx inspect

Then you can do multi-platform Docker builds like this:
docker buildx build --platform linux/amd64,linux/arm64 .

I want a simple, fast and lightweight text editor for my Linux desktop. I don’t want to learn a lot of new arcane key bindings, so not Vim or Emacs. I want a real GUI desktop application, not a console based one, so not nano (even though nano is nice when you only have a text console available). I don’t want a full-blown IDE for programming (I already have that) so I don’t need syntax highlighting and similar features.

I regularly use Swedish keyboard layout, but I keep the English layout around in case I would like to temporary switch to it.

Ubuntu 14.04 sometimes mess this up and I suddenly get English layout when I log in. I fix this by installing dconf-editor, go to desktop/ibus/general, and make sure that the values engines-order and preload-engines are the same and in the desired order with the default layout first.

I use Adobe Lightroom 4.4 for photo editing. There is one very annoying aspect of this program, it is not available for Linux (only for Windows and Max OS X).

In order to run Lightroom on my computer, I had to use VirtualBox and install Windows 7 in it. This works, but is quite clumsy and annoying. And since Lightroom is the only reason for me to run Windows, I would like to get rid of it.

Jetty is a popular open source Java application server. In order to run it as a service on a Linux server, they recommend using a horribly overcomplicated and quite fragile script.

In Ubuntu server, there is a better way. Leverage Upstart and its declarative job definitions.

First install Jetty into /opt/jetty and create a jetty user:

useradd --user-group --shell /bin/false --home-dir /opt/jetty/temp jetty

Then create a file /etc/init/jetty.conf with content like this:

I use Adobe Lightroom 4.4 for photo editing. There is one very annoying aspect of this program, it is not available for Linux (only for Windows and Max OS X).

In order to run Lightroom on my computer, I had to use VirtualBox and install Windows 7 in it. This works, but is quite clumsy and annoying. And since Lightroom is the only reason for me to run Windows, I would like to get rid of it.

This is no longer relevant, since the PPA have updated to GIMP 2.8.10, which has fixed the bug.

If you use Ubuntu 12.04 LTS, you only have access to the old GIMP 2.6 in the standard repositories. This is unfortunate since GIMP 2.8 have a lot of new useful features.

The standard way to get GIMP 2.8 is to use the a PPA, as described here. This used to work fine. However, then the PPA upgraded to GIMP 2.8.6, which contains a horrible UI bug (seems like neither the GIMP team, nor the PPA maintainer has any particularly strong QA process).

These instructions are tested with Ubuntu desktop 12.04, but will probably be useful in other Linux distros with GRUB2 as well.

The goal is to block everything except booting the default system. In paricular, it should not be possible for anyone to boot into recovery mode, since that will bypass normal login and give root access directly.

1. Run grub-mkpasswd-pbkdf2 from a terminal and enter the desired password, copy the output.
2. Edit /etc/grub.d/40_custom and add this to the end:

set superusers="root"
password_pbkdf2 root output from grub-mkpasswd-pbkdf2 goes here
password bogus bogus

3. Make /etc/grub.d/40_custom non-readable for users:
   chmod o-r /etc/grub.d/40_custom
4. Edit /etc/grub.d/10_linux according to this diff:

90c90,94
<   printf "menuentry '${title}' ${CLASS} {\n" "${os}" "${version}"
---
>   if ${recovery} || ${in_submenu}; then
>     printf "menuentry '${title}' ${CLASS} --users '' {\n" "${os}" "${version}"
>   else
>     printf "menuentry '${title}' ${CLASS} {\n" "${os}" "${version}"
>   fi
258c262
<     echo "submenu \"Previous Linux versions\" {"
---
>     echo "submenu \"Previous Linux versions\" --users '' {"

5. Edit /etc/grub.d/20_memtest86+ according to this diff:

27c27
< menuentry "Memory test (memtest86+)" {
---
> menuentry "Memory test (memtest86+)" --users "" {
33c33
< menuentry "Memory test (memtest86+, serial console 115200)" {
---
> menuentry "Memory test (memtest86+, serial console 115200)" --users "" {
46c46
< #menuentry "Memory test (memtest86+, experimental multiboot)" {
---
> #menuentry "Memory test (memtest86+, experimental multiboot)" --users "" {
52c52
< #menuentry "Memory test (memtest86+, serial console 115200, experimental multiboot)" {
---
> #menuentry "Memory test (memtest86+, serial console 115200, experimental multiboot)" --users "" {

6. Run update-grub

(I am not sure if it is possible to abuse memtest86+, but better safe than sorry.)

Ubuntu has mechanism to log user activity such as used documents. This is used to facilitate searching, but can also be intrusive to your privacy.

Here is a way to disable this logging without breaking Unity or any other part of the system, execute these commands in a terminal:

1. sudo mv /etc/xdg/autostart/zeitgeist-datahub.desktop /etc/xdg/autostart/zeitgeist-datahub.desktop-inactive
2. rm ~/.local/share/recently-used.xbel
3. mkdir ~/.local/share/recently-used.xbel
4. rm -rf ~/.local/share/zeitgeist

then log out and log in again.

The new Ubuntu release 11.04 Natty contains the new Unity desktop environment which is quite controversal. I have tried it for a while and I think it is neat but too buggy and immature. However, it is easy to revert to the old Gnome 2 desktop environment and have things working almost as in 10.10.

First do a normal distribution upgrade to 11.04, then go to System Settings -> Login Screen and select Ubuntu Classic as default session and reboot.