Tutorial

Resolve git am Merge Conflicts

5 minutes to read

TL;DR: After git am encounters a merge conflict, the output of git status and the working tree’s state do not show any sign of conflict like a git pull, git merge, or git rebase conflict does, which can be very confusing. To get an experience that is at least somewhat similar to those other Git commands, use git am --reject. Problem When git am is used to apply patches and encounters a merge conflict, it will print a message like this: …

Enable Wi-Fi by Default on OpenWrt

7 minutes to read

On routers with an Ethernet port, OpenWrt has Wi-Fi disabled on the first boot “for security reasons.”1 To enable Wi-Fi, users need to first connect a device to the router via Ethernet, so they can access the router in a wired manner and change its configuration to set up Wi-Fi. This is more inconvenient than most routers’ stock firmware. These routers come with a unique default SSID and password printed on a sticker affixed to the router, and for the initial setup, users can connect to the router wirelessly using these credentials; Ethernet is not required. OpenWrt, however, cannot easily make use of default Wi-Fi credentials. Constant initial Wi-Fi password in the default configuration (which would be common for every OpenWrt device on the first boot) is certainly a security risk; randomized passwords are more secure, but there is no means to inform users of the random password before the users have connected to the router, unlike what router manufacturers can do with the sticker. Therefore, disabling Wi-Fi by default on OpenWrt does improve security. …

Create an External-Facing IPv6 Subnet on OpenWrt

20 minutes to read

Some home Internet users have a need to expose some devices on their home network to the Internet and meanwhile block external access to other devices. For example, some users may wish to allow external access to their home server and prevent their smartphones and workstations from being accessible from the Internet. To achieve this goal, these users can create a subnet exposed to the Internet on their router and put the external-facing devices into this subnet; the other devices can thus be kept on the default local area network (LAN) subnet, protected behind a firewall that blocks external access. The external-facing subnet is commonly referred to as a demilitarized zone (DMZ). …

Slipstream Windows NT 4.0 SP6a into Installation Media

7 minutes to read

Microsoft has once released official Windows installation media with a service pack integrated, such as Windows Vista with SP1 and Windows XP with SP2. The process of integrating a service pack into the installation media is called slipstreaming. By using such a slipstreamed media, users need not install the slipstreamed service pack separately after they have installed Windows. For Windows NT 4.0 Workstation, the latest slipstreamed official installation media that can be found online only have SP1, whereas the latest service pack for Windows NT 4.0 is SP6a. This is unlike Windows 2000, XP, Vista, or 7, all of which have official installation ISOs with the latest available service pack slipstreamed. …

Trim Linux Kernel Configuration

14 minutes to read

Many Linux users who prefer to compile their own kernels definitely want to reduce kernel compilation time and minimize the on-disk footprint of compiled kernels and modules. Achieving these goals is commonly done by trimming the kernel configuration, which entails disabling kernel configuration options that the user does not need. Users can disable options for software features they do not use and hardware that they do not own; for example, those who do not need to use WireGuard can disable it in their kernel configuration, and those who do not own an AMD graphics card or an AMD CPU with integrated graphics can disable the amdgpu driver at kernel build time. …

Set Up a Custom Gentoo Binary Package Host

Updated: 25 minutes to read

Gentoo is a GNU/Linux distribution where users themselves can easily build software packages for the entire operating system from source code. For a long time, building packages on their own was the only choice Gentoo users had because Gentoo only distributed the scripts (i.e. ebuilds) to build the packages, not the packages’ ready-to-run, pre-built binaries like on other distributions. Compiling software packages for a whole operating system takes a considerable amount of time, and Gentoo users had had to deal with it. This all changed at the end of 2023, when the official Gentoo binary package host was launched. It has been providing users with pre-built binary packages for many software packages available in the Gentoo ebuild repository, and users can install these binary packages to skip the build process, thus saving time. …

Build the Same LaTeX Input File Differently According to Command-Line Options

10 minutes to read

You might have encountered situations where you would like to produce different versions of the same document or create several related documents from a single source, such as: All your document versions have exactly the same content, but each version is formatted differently. Example: In parallel with a standard version of your document, you might also want to create a more accessible version of it that uses a larger font size. …

Minimize Steam When Launching a Game Shortcut on Windows

5 minutes to read

The recent Steam client major update has brought predominant user interface changes as well as a regression in user experience: if the Steam client is not running, and the user launches a Steam game from its desktop or Start menu shortcut, then the Steam client window will show up before the game launches; prior to the update, Steam would start minimized in this case, thus the window would not show up on its own. …

Avoid Creating -9999-only Gentoo Packages

Updated: 21 minutes to read

Some Gentoo packages provide a special 9999 version; by convention, the ebuild that bears the 9999 version is a live ebuild, which builds the package from its “live” sources in the project’s version control system (VCS) repository – e.g. a Git repository – instead of “non-live” sources in a .zip or a .tar.* archive. The project’s sources in the VCS repository are usually subject to frequent changes due to development activities, hence they are “live”. …

Run Windows 98 in Vanilla DOSBox

14 minutes to read

As a DOS emulator, DOSBox is theoretically capable of running DOS-based versions of Windows, like Windows 3.1, 95, and 98. Certainly, the compatibility list on DOSBox official website classifies Windows 3.1 and 95 as supported; but for Windows 98, it is just rated runnable – even lower than the intermediate playable tier. Perhaps for this reason, most people would just resort to other DOSBox forks that offer better support for Windows 98, like DOSBox-X, when they want to run this version of Windows. …

Gentoo Configuration Guide: Full Disk LUKS2 with GRUB and systemd

Updated:

This collection is a tutorial which provides instructions to set up LUKS2-based full disk encryption on a Gentoo system using GRUB as the bootloader and systemd as the init system. In particular, setting up LUKS2 for use with GRUB is especially tricky, and this tutorial addresses any intricacies there. This tutorial aims to support both new Gentoo installations and existing ones, so it can be used to encrypt an unencrypted system too. …

Use Git to Manage Kernel Sources on Gentoo

Updated: 12 minutes to read

Gentoo offers its users a wide array of Linux kernel packages in the sys-kernel/* category, each of which may install the kernel in a different way. In particular, the sys-kernel/*-sources packages (such as sys-kernel/gentoo-sources, sys-kernel/vanilla-sources) install only the kernel’s source code and do nothing else. This is suitable for users who prefer to compile and install the kernel on their own but still would like to let the system package manager update the kernel sources automatically. …

Refine Gentoo on Windows Subsystem for Linux

8 minutes to read

This article covers some information that can help perfect a Gentoo installation on Windows Subsystem for Linux (WSL) to maximize its performance, improve its interoperability with Windows, and even unlock new system capabilities. Originally, I had been planning to write a full Gentoo on WSL installation tutorial during September of the last year, but that tutorial was only halfway done before I had to move on for something more important in my real life, which is why I have disappeared from my personal site for almost another half of year (though you could find my development activities on GitHub if you looked at my profile). Now that I can enjoy a short break with some peace of mind, I have decided to at least complete that tutorial. But before I started, I happened to search for “Gentoo WSL” on Google out of curiosity. While I had been away, there was a new Gentoo in WSL article on Gentoo Wiki originally created on November 24, 2021. That article already covers the bulk of what I wanted to mention in my tutorial in a very concise way, and it is easy to find thanks to the fact that it is on Gentoo Wiki, thus I could no longer see the value of repeating the identical things in lengthy and verbose paragraphs on my personal site. …

Gentoo Configuration Guide: systemd

Updated: 5 minutes to read

As of now, the Gentoo Handbook, which is the official Gentoo installation guide, mainly focuses on steps to install a system based on OpenRC instead of systemd. After all, as a project mainly maintained by Gentoo developers, it would be a surprise if Gentoo did not introduce OpenRC as the distribution’s init system with primary support. For people who want to use systemd on Gentoo, the Handbook does include some instructions in itself, but it sometimes asks the users to refer to the standalone systemd article too. In my opinion, that article is very comprehensive but is not well organized: steps that should be performed during the installation process scatter around the entire article, making it easy to miss required steps. Therefore, this article is created as my effort to come up with a clear and working procedure for getting systemd to work on Gentoo. …

Gentoo Configuration Guide: GNOME on systemd

Updated: 5 minutes to read

Getting a perfect GNOME configuration on Gentoo is not hard but is tricky. In other words, it would be a piece of cake once you have done it, but it is not easy to get it right with only one shot for the first time. The GNOME Guide on Gentoo Wiki is a good resource and is enough for a barely functional GNOME installation, but there are plenty of rooms for improvements, like removing the authentication dialog when modifying network settings, and enabling Wayland screen sharing in web browsers like Google Chrome. …

Create a CPU Frequency and Temperature Monitoring Bash Script for Linux-based Systems

4 minutes to read

This post will show you a way to monitor CPU frequency and temperature on Linux-based systems without aid of any programs or packages that are not commonly preinstalled on major GNU/Linux distributions. No extra hardware drivers are required: the magic is done merely by a short Bash script in just a few lines that only relies on mechanisms provided by the Linux kernel itself and some most essential Unix commands. …

Use Btrfs on Fedora Installed from a Raw Image

8 minutes to read

Fedora is moving to Btrfs for its default file system on its “desktop variants” in Fedora 33. This change is welcomed by some users because of some benefits Btrfs is offering. Other Fedora variants still default to ext4, although users may elect to use Btrfs during system installation with the Anaconda installer. But for non-desktop-variant raw image distributions like the Minimal aarch64 image, you do not have the chance to choose a file system other than ext4, because you are applying the image directly instead of using Anaconda. This post will show you how to use Btrfs on a Fedora installation derived from such image by converting the file system after the image is applied. …

USB Issue on Raspberry Pi 4 Running Fedora - Complex Solution

Updated: 7 minutes to read

In the previous post we looked at a very simple solution to fix the USB ports on Raspberry Pi 4B 4GB/8GB RAM models running Fedora, which involves a trade-off between the USB ports' functionality and the amount of RAM available to the operating system. This post will give you another solution that takes more steps but no longer limits available memory to 3 GiB. As said in the previous post, no action is required for the 2GB model. The symptoms of this issue are available there as well. …

USB Issue on Raspberry Pi 4 Running Fedora - Simple Solution

3 minutes to read

When Fedora runs on Raspberry Pi 4B 4GB/8GB RAM models, the USB ports might not be working out-of-box as of Fedora 32 and Linux kernel 5.8. In this post, I will introduce a very simple solution to this problem that only requires you to add one line to a configuration file. Notes and Caveats If you are using the 2GB model, then rest assured - the USB ports should work out-of-box, and you do not need to do anything. This issue exists only on the 4GB and 8GB models. …

Build a Multilingual Jekyll Site

Updated:

Jekyll is a static website generator. It creates static HTML documents directly, making hosting a website as easy as setting up an HTTP server. Yet it is still very powerful: it can generate HTML documents from Markdown, which makes writing and formatting articles and posts easy and fun; it supports plugins that add more feature to itself, the generated site, or even both. Thanks to plugin developers, we have multilingual plugins for Jekyll which allow us to make our site useful to more people in different parts of the world by presenting translated and localized contents. However, there are still a few things that require extra care and some possible improvements on the site’s user experience that are not offered by those plugins, which will be covered by the guides in this collection. We will walk through all the steps needed to set up a multilingual Jekyll site similar to the one you are currently viewing. …

Perform Manual dnf history undo

8 minutes to read

My choices of GNU/Linux distributions are Fedora for desktop computers and CentOS for servers. Both of them feature DNF - Red Hat’s package manager front-end for RPM, which is the primary reason I use these distributions. Although one might argue that it is slow, DNF is very clear on not only what it will do for an action but also what it has done: it maintains a history of package installation and removal operations, which are called “transactions”. You can undo a transaction with dnf history undo or roll back to a previous state with dnf history rollback. Other common package managers, like APT and Pacman, also save operation logs, but they generally do not offer a similar operation reverting functionality. …

Install Raspberry Pi’s vcgencmd on Fedora

Updated: 5 minutes to read

This post is a continuation of my previous one about setting up a cluster of Raspberry Pis running Fedora. After I got the cluster to compute something, @ColsonXu, the cluster’s owner, asked me if I could monitor the CPU temperature of each Raspberry Pi by running this command: $ /opt/vc/bin/vcgencmd measure_temp The vcgencmd program is included in Raspberry Pi OS (formerly called Raspbian) as a utility for retrieving information about Raspberry Pi’s hardware. However, it is not included in Fedora’s software repositories. Luckily though, the source code of vcgencmd, along with the entire userland package that contains the program, is available, so we can compile it on our own. …

Set Up Fedora on a Raspberry Pi Cluster

14 minutes to read

First and foremost, I would like to thank @ColsonXu for giving me this opportunity to play with some Raspberry Pis. He had got a few Raspberry Pi 4’s and built a cluster with them for computing purposes, but there was nothing to compute until the morning when @mrdarcychen found an article about running Rosetta@home on Raspberry Pi from Fedora Magazine, and Colson approved the plan. I was able to take the job of installing software required to run Rosetta@home on the Raspberry Pis. …

Use Cygwin’s Shell or Git Bash in Windows Terminal

5 minutes to read

Recently, Microsoft has made the first stable release of Windows Terminal, a new terminal program for Windows 10. Windows Terminal allows you to add and use multiple shells, like Windows PowerShell, the old command prompt, and any shell in your Windows Subsystem for Linux (WSL) environments. It also provides way more features and customization options than the old Windows console host conhost.exe, which has been used for command prompt and WSL. …

Share GTA V Game Files Between Steam and Epic Games

Updated: 5 minutes to read

After Epic Games announced that it would give away free copies of GTA V for a week, many people started to claim this gift on that game platform. Even some existing GTA V players who have already purchased the game on Steam had decided to get another free copy so they could have two or more GTA Online accounts. It appears that if you have already installed GTA V via Steam, you still need to download a full copy of the game files via Epic Games. However, by doing some tricks, you can let Steam and Epic Games share the same set of GTA V game files to avoid downloading the game again and thus save disk space. We will use the MKLINK command on Windows, which is not well-known, to create a link to the existing game files. The link works as if the linked files and folders are exactly there, but it occupies very little space. …