Tag Archives: Linuxcom

An Introduction to Linux Virtual Interfaces: Tunnels | Linux.com


Linux has supported many kinds of tunnels, but new users may be confused by their differences and unsure which one is best suited for a given use case. In this article, I will give a brief introduction for commonly used tunnel interfaces in the Linux kernel. There is no code analysis, only a brief introduction to the interfaces and their usage on Linux. Anyone with a network background might be interested in this information. A list of tunnel interfaces, as well as help on specific tunnel configuration, can be obtained by issuing the iproute2 command ip link help.

This post covers the following frequently used interfaces:

After reading this article, you will know what these interfaces are, the differences between them, when to use them, and how to create them.

Read more at Red Hat Developers 

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Move your Dotfiles to Version Control | Linux.com


There is something truly exciting about customizing your operating system through the collection of hidden files we call dotfiles. In What a Shell Dotfile Can Do For You, H. “Waldo” Grunenwald goes into excellent detail about the why and how of setting up your dotfiles. Let’s dig into the why and how of sharing them.

What’s a dotfile?

“Dotfiles” is a common term for all the configuration files we have floating around our machines. These files usually start with a . at the beginning of the filename, like .gitconfig, and operating systems often hide them by default. For example, when I use ls -a on MacOS, it shows all the lovely dotfiles that would otherwise not be in the output.

dotfiles on master
➜ ls
README.md  Rakefile   bin       misc    profiles   zsh-custom

dotfiles on master
➜ ls -a
.               .gitignore      .oh-my-zsh      README.md       zsh-custom
..              .gitmodules     .tmux           Rakefile
.gemrc          .global_ignore .vimrc           bin
.git            .gvimrc         .zlogin         misc
.gitconfig      .maid           .zshrc          profiles

If I take a look at one, .gitconfig, which I use for Git configuration, I see a ton of customization. I have account information, terminal color preferences, and tons of aliases that make my command-line interface feel like mine. 

Read more at OpenSource.com

How to Monitor Disk IO in Linux | Linux.com


iostat is used to get the input/output statistics for storage devices and partitions. iostat is a part of the sysstat package. With iostat, you can monitor the read/write speeds of your storage devices (such as hard disk drives, SSDs) and partitions (disk partitions). In this article, I am going to show you how to monitor disk input/output using iostat in Linux. So, let’s get started.

Installing iostat on Ubuntu/Debian:

The iostat command is not available on Ubuntu/Debian by default. But, you can easily install the sysstat package from the official package repository of Ubuntu/Debian using the APT package manager. iostat is a part of the sysstat package as I’ve mentioned before.

First, update the APT package repository cache with the following command:

Read more at LinuxHint

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C Programming Tutorial Part 3 – Variables Basics | Linux.com


Up until now, we’ve discussed the basics of what a C program is, how to compile and execute it, and what are preprocessors. If you have gone through these tutorials, it’s time we discuss the next topic, which is variables. 

Variables are one of the core elements of C programming as they store values for programmers to use as per their requirement. Let’s understand their basics through an example. Following is a basic C program:

#include <stdio.h>

int main (void)
{
 int a = 10;
 char b = 'z';
 float c = 1.5;
 printf("n a=%d, b=%c, c=%f n", a,b,c);
 return 0;
}

In previous C programming tutorials, we have already explained things like what is ‘stdio.h,’ what does ‘#include’ mean, and what is a function (especially ‘main’). So, we’ll directly jump onto the variables part.

Read more at HowToForge

Introduction to YAML: Creating a Kubernetes Deployment | Linux.com


There’s an easier and more useful way to use Kubernetes to spin up resources outside of the command line: creating configuration files using YAML. In this article, we’ll look at how YAML works and use it to define first a Kubernetes Pod, and then a Kubernetes Deployment.

YAML Basics

It’s difficult to escape YAML if you’re doing anything related to many software fields — particularly Kubernetes, SDN, and OpenStack. YAML, which stands for Yet Another Markup Language, or YAML Ain’t Markup Language (depending who you ask) is a human-readable text-based format for specifying configuration-type information. For example, in this article, we’ll pick apart the YAML definitions for creating first a Pod, and then a Deployment.

Using YAML for K8s definitions gives you a number of advantages, including:

  • Convenience: You’ll no longer have to add all of your parameters to the command line
  • Maintenance: YAML files can be added to source control, so you can track changes
  • Flexibility: You’ll be able to create much more complex structures using YAML than you can on the command line

YAML is a superset of JSON, which means that any valid JSON file is also a valid YAML file. So on the one hand, if you know JSON and you’re only ever going to write your own YAML (as opposed to reading other people’s) you’re all set. On the other hand, that’s not very likely, unfortunately. Even if you’re only trying to find examples on the web, they’re most likely in (non-JSON) YAML, so we might as well get used to it.  Still, there may be situations where the JSON format is more convenient, so it’s good to know that it’s available to you.

Read more at CNCF