I made some changes to /etc/sysctl.conf. I know it will take effect next time Linux boots. However, how to make the changes to sysctl.conf take effect without rebooting Linux? You can force Linux to reload the new configuration in /etc/sysctl.conf by: execute the following command as root: sysctl -p For more details, check the manual…
How to make a swap partition on Linux? First, make a new partition (or reuse an existing one if you like). I suggest using cfdisk to create it: https://www.systutorials.com/docs/linux/man/8-cfdisk/ Then, turn the new partition (say, /dev/sdc1) to a swap # mkswap /dev/sdc1 Lastly, turn it on # swapon /dev/sdc1 You can check whether its status…
How to set swap priority in Linux? Can I use 2 swap partition at the same time? You can set the priority of swap in Linux by swapon. For example, to set /dev/sdc1‘s priority to 0: # swapoff /dev/sdc1; swapon -p 0 /dev/sdc1 You can also put one entry into the /etc/fstab to make it…
Each time I play a video and lock the iPhone by pushing the power button, the video is automatically stopped. If I want to play a MTV and just listen to the music when I walking, I’d like the video play in the background. Is there a method to make this happen? I can do…
There is a ‘/b/’ in the posts’ URLs on fclose.com . What does it mean? It originally means “blog” when the blogs are first set up. This site changes to not only a blog (one good example is this forum) over time. However, the URLs are kept unchanged and the ‘/b/’ has no special meanings…
As a WordPress user, you may have noticed that the default HTML editor lacks some of the features that you need for your content. Fortunately, you can add custom buttons to the WordPress HTML editor to make your content creation experience more efficient and productive. In this post, we will explore how to add custom…
What are the Google Chrome keyboard and mouse shortcuts for Linux and Windows? Keyboard shortcuts of Chrome can make it easier to control the browser and save our time. Here are a list of commonly used shortcuts: Ctrl+T Opens a new tab. Press Ctrl and click a link. Or click a link with your middle…
How to set the global user name and user email for git? We may be asked to set our global user name and user email if it is the first time that we use git on a machine: Your name and email address were configured automatically based on your username and hostname. Please check that…
How to efficiently archive a very large sparse file, say 1TB? The sparse file may contains a small amount of data, say 32MB. SEEK_HOLE and SEEK_DATA The SEEK_HOLE/SEEK_DATA functionalities play the trick and makes `tar` and `cp` handle the large sparse file very efficiently. `lseek` with `SEEK_HOLE` returns the offset of the start of the…
Introduction In this tutorial, we will be learning as how to deploy .NET Core 2.0 MVC web application on Microsoft Public Cloud i.e. Microsoft Azure, using Microsoft Visual Studio 2017 v15.3 For novice Cloud developers, aspiring .NET / Cloud architects, and all other IT professionals associated with the .NET Core framework & Cloud computing, especially…
Introduction In general, if we want to debug Linux Kernel, there are lots of tools such as Linux Perf, Kprobe, BCC, Ktap, etc, and we can also write kernel modules, proc subsystems or system calls for some specific debugging aims. However, if we have to instrument kernel to achieve our goals, usually we would not…
Abstract Most popular task monitor systems (such as top, iotop, proc, etc) can only get tasks’ disk I/O information like tasks’ I/O utilization percentage every seconds due to kernel timer/tick frequency and high time cost of system interfaces. This article presents I/O Microscopy, a new way to get tasks’ disk I/O information with high accuracy….
With Google algorithm becoming more intelligent with each passing day, the margin for errors has significantly reduced over the past decade. Back in the day, you might get away with keyword stuffing but today, the same offense will strike off your website from Google search engine results. No one wants that, right. To save you…
The word “viral” has received a lot of attention over the last few years and is applied to different types of content to describe how quickly it has spread and gained popularity. Many times, you’ll hear people speak about their idea and how fast it will spread while assuming that it will “go viral”, but…
Call forwarding is useful if you are expected to be unavailable for receiving calls or lose cell phone coverage for some time. Call forwarding is not something that is “new” to modern phones. It is a feature which is invented in 1960s (the patent expired in 1980) of some telephone switching systems. But with iPhone/iOS,…
Building Linux kernel may sound a complex and geek-only thing. However, as Linux kernel itself has much less depended tools/packages compared to other software packages, it is quite easy to compile, build and install a Linux kernel from the source code in an existing Linux OS. Building Linux kernel is needed if you need to…
In today’s time, data visualization has become a significant part of the success story of an organization. With the help of right techniques, visualizing data can reveal insights which the management staff can use in their decision-making in order to make sound data-driven decisions. Mapping software is among the robust data visualization tools that you…
Motivation Recently, I find it is hard to know the percentage of time that one process uses to wait for synchronous I/O (eg, read, etc). One way is to use the taskstats API provided by Linux Kernel [1]. However, for this way, the precision may be one problem. With this problem, I dig into Linux…
Making a career choice is difficult. And, if you have decided on becoming a programmer, the difficulty is just beginning. The most important thing is to first decide the language that you want to learn and this is often the most difficult decision. The good part is that you know you need to focus on…
There are many Vim tutorials and Vim tips on the Web. However, I find the vimtutor provides the best tutorial among those so far as I found on the Web while the vimtutor seems usually reachable from a terminal which is not obviously known to Vim beginners who are usually Linux beginners too. This page…