If you have sent any plaintext confidential emails to someone (most likely you did), have you ever questioned yourself about the mail being tampered with or read by anyone during transit? If not, you should!

Any unencrypted email is like a postcard. It can be seen by anyone (crackers/security hackers, corporations, governments, or anyone with the required skills), during its transit.

In 1991 Phil Zimmermann, a free speech activist, and anti-nuclear pacifist developed Pretty Good Privacy (PGP), the first software available to the general public that utilized RSA (a public key cryptosystem, will discuss it later) for email encryption and signing. Zimmermann, after having had a friend post the program on the worldwide Usenet, got prosecuted by the U.S. government; later he was charged by the FBI for illegal weapon export because encryption tools were considered as such (all charges were eventually dropped). Zimmermann later founded PGP Inc., which is now part of Symantec Corporation.

In 1997 PGP Inc. submitted a standardization proposal to the Internet Engineering Task Force. The standard was...

Markdown is a widely used markup language, which is now not only used for creating documentation or notes but also for creating static websites (using Hugo or Jekyll). It is supported by major sites like GitHub, Bitbucket, GitLab, Stack Exchange, and Reddit.

Markdown follows a simple easy-to-read and easy-to-write plain text formatting syntax. By just using non-alphabetic characters like asterisk (*), hashtag (#), backtick (`), or dash (-), you can format text as bold, italics, lists, headings, tables and so on.

Now, to write in Markdown, you can choose any Markdown applications available for Windows, macOS, and Linux desktop. You can even use web-based in-browser Markdown editors like StackEdit. But if you’re specifically looking for the best Markdown editor for Linux desktop, I present you two Markdown editors: Mark Text and Typora.

I’ve also tried other popular Markdown apps available for Linux platforms such as Joplin, Remarkable, ReText, and Mark My Words. But the reason I chose Mark Text and Typora is the seamless live preview features with distraction free user interface. Unlike other...

Transmission Control is an essential aspect of network activity and governs the behavior of many services we take for granted. When sending your emails or just browsing the web you are relying on TCP to send and receive your packets in a reliable fashion. Thanks to two DARPA scientists, Vinton Cerf and Bob Kahn who developed TCP/IP in 1970, we have a specific set of rules that define how we communicate over a network. When Vinton and Bob first conceptualized TCP/IP, they set up a basic network topology and a device that can interface between two other hosts.

In the Figure 1 we have two networks connected by a single gateway. The gateway plays an essential role in the development of any network and bares the responsibility of routing data properly between these two networks.

Since the gateway must understand the addresses of each host on the network, it is necessary to have a standard format in every packet that arrives. Vince and Bob called this the internetwork header prefixed to the packet by the source host.

The source and destination entries, along with the IP address, uniquely...

At times, we need to write shell scripts that are interactive and user executing them need to monitor the progress. For such requirements, we can implement a simple progress bar that gives an idea about how much task has been completed by the script or how much the script has executed.

To implement it, we only need to use the “echo” command with the following options and a backslash-escaped character.

-n : do not append a newline
-e : enable interpretation of backslash escapes
r : carriage return (go back to the beginning of the line without printing a newline)

For the sake of understanding, we will use “sleep 2” command to represent an ongoing task or a step in our shell script. In a real scenario, this could be anything like downloading files, creating backup, validating user input, etc. Also, to give an example we are assuming only four steps in our script below which is why we are using 20,40,60,80 (%) as progress indicator. This can be adjusted as per the number of steps in a script. For instance, a script with three steps can be represented by 33,66,99 (%) or a script with ten steps...

Just two days ago, Ubuntu marked the 16th anniversary of its first ever release, Ubuntu 4.10 “Warty Warthog,” which showed Linux could be a more user friendly operating system.

Back to now, after the six months of development cycle and the release of the current long-term Ubuntu 20.04 “Focal Fossa,” Canonical has announced a new version called Ubuntu 20.10 “Groovy Gorilla” along with its seven official flavor: Kubuntu, Lubuntu, Ubuntu MATE, Ubuntu Kylin, Xubuntu, Ubuntu Budgie, and Ubuntu Studio.

Ubuntu 20.10 is a short term or non-LTS release, which means it will be supported for 9 months until July 2021. Though v20.10 does not seem a major release, it does come with a lot of exciting and new features. So, let’s see what Ubuntu 20.10 “Groovy Gorilla” has to offer:

New Features in Ubuntu 20.10 “Groovy Gorilla”

Ubuntu desktop for Raspberry Pi 4

Starting with one of the most important enhancements, Ubuntu...

Introduction

The btrfs filesystem has taunted the Linux community for years, offering a stunning array of features and capability, but never earning universal acclaim. Btrfs is perhaps more deserving of patience, as its promised capabilities dwarf all peers, earning it vocal proponents with great influence. Still, none can argue that btrfs is unfinished, many features are very new, and stability concerns remain for common functions.

Most of the intended goals of btrfs have been met. However, Red Hat famously cut continued btrfs support from their 7.4 release, and has allowed the code to stagnate in their backported kernel since that time. The Fedora project announced their intention to adopt btrfs as the default filesystem for variants of their distribution, in a seeming juxtaposition. SUSE has maintained btrfs support for their own distribution and the greater community for many years.

For users, the most desirable features of btrfs are transparent compression and snapshots; these features are stable, and relatively easy to add as a veneer to stock CentOS (and its peers). Administrators are...

The Internet has become the number one resources for news, information, events, and all things social. As most people know there are many ways to create a website of your own and capture your own piece of the internet to share your stories, ideas, or even things you like with others. When doing so it is important to make sure you stay protected on the internet the same way you would in the real world. There are many steps to take in the real world to stay safe, however, in this article we will be talking about staying secure on the web with an SSL certificate.

OpenSSL is a command line tool we can use as a type of "bodyguard" for our webservers and applications. It can be used for a variety of things related to HTTPS, generating private keys and CSRs (certificate signing requests), and other examples. This article will break down what OpenSSL is, what it does, and examples on how to use it to keep your website secure. Most online web/domain platforms provide SSL certificates for a fixed yearly price. This method, although it takes a bit of technical knowledge, can save you some money and keep...

Simply put, a Shell Script is a program that is run by a UNIX/Linux shell. It is a file that contains a series of commands which are executed sequentially as if they were entered on the command line interface (CLI) or terminal.

In this quick tutorial on Shell Scripting, we will write a simple program to toss a coin. Basically, the output of our program should be either HEADS or TAILS (of course, randomly).

To start with, the first line of a shell script should indicate which interpreter/shell is to be used to execute the script. In this tutorial we will be using /bin/bash and it will be denoted as #!/bin/bash which is called a shebang!

Next, we will be using an internal Bash function - a shell variable named RANDOM. It returns a random (actually, pseudorandom) integer in the range 0-32767. We will use this variable to get 2 random values – either 0 (for HEADS) or 1 (for TAILS). This will be done via a simple arithmetic operation in shell using % (Modulus operator, returns remainder), $((RANDOM%2)) and this will be stored in a result variable. So, the second line of our program becomes...

Killing Zombies!

Also known as “defunct” or “dead” process – In simple words, a Zombie process is one that is dead but is present in the system’s process table. Ideally, it should have been cleaned from the process table once it completed its job/execution but for some reason, its parent process didn’t clean it up properly after the execution.

In a just (Linux) world, a process notifies its parent process once it has completed its execution and has exited. Then the parent process would remove the process from process table. At this step, if the parent process is unable to read the process status from its child (the completed process), it won’t be able to remove the process from memory and thus the process being dead still continues to exist in the process table – hence, called a Zombie!

In order to kill a Zombie process, we need to identify it first. The following command can be used to find zombie processes:

$ ps aux | egrep "Z|defunct"

Z in the STAT column and/or [defunct] in the last (COMMAND) column of the output would identify a Zombie process.

Now practically you can’t kill a Zombie...

Let’s get to know the Linux Command Line Interface (CLI).

• Introduction
• A bit of history
• First look at the command line
• Command syntax
• Notes
• Basic commands
  • pwd
  • ls
  • file
  • cat
  • cd
  • clear
  • history
  • cp
  • mv
  • rm

Introduction

The Linux command line is a text interface to your computer.

Also known as shell, terminal, console, command prompts and many others, is a computer program intended to interpret commands.

Allows users to execute commands by manually typing at the terminal, or has the ability to automatically execute commands which were programmed in “Shell Scripts”.

A bit of history

The Bourne Shell (sh) was originally developed by Stephen Bourne while working at Bell Labs.

Released in 1979 in the Version 7 Unix release distributed to colleges and universities.

The Bourne Again Shell (bash) was written as a free and open source replacement for the Bourne Shell.

Given the open nature of Bash, over time it has been adopted as the default shell on most Linux systems.

First look at the command line

Now that we have covered some basics, let’s open a terminal window and see how it looks!

When a terminal is...

Last week, a Red Hat-sponsored community project, Fedora, announced the availability of Fedora 33 Beta. It is a prerelease version of the upcoming Fedora 33 Linux distribution, whose final stable version will arrive in the last week of October.

Fedora 33 is one of the exciting releases as it contains the fundamental shift of the default filesystem from ext4 to btrfs for all Fedora desktop editions and spins, along with other new features and visual changes.

Here are some of the key updates that Fedora 33 Beta includes:

• GNOME 3.38 desktop environment
• Linux Kernel 5.8
• GNU Nano as default terminal text editor
• earlyOOM enabled by default in Fedora 33 KDE
• Fedora IoT as an official edition
• Package update like Ruby, Python, and Perl

For complete details of all features, you can check out the Fedora 33 change set.

Coming to the main topic, you can also upgrade your current Fedora system to the beta version of Fedora 33, which you’ll also be able to upgrade further to the final stable release by simply updating your system once it arrives at the end of October.

So, if you’re the one who wants...

As the Linux Mint team is progressing to release the first point version of Linux Mint 20 series, its founder and project leader Clement Lefebvre has finally revealed the codename for Linux Mint 20.1 as “Ulyssa”. He has also announced that Mint 20.1 will most probably arrive in mid-December (just before Christmas).

Until you wait for its beta release to test Linux Mint 20.1, Clement has also shared some great news regarding the new updates and features that you’ll get in Mint 20.1.

First, packaging of open source Chromium web browser and its updates directly through the official Mint repositories. As the team noticed delays between the official release and the version available in Linux distros, it has now decided to set up their own packaging and build Chromium package based on upstream code, along with some patches from Debian and Ubuntu as well.

As a result, the first test build of Chromium is available to download from here.

In last month's blog, the Mint team introduced a new WebApp Manager, inspired by Peppermint OS and its SSB...

Editor's note: Thank you to returning contributor Matthew Higgins for these reflections on what the return and preservation of Linux Journal means.

As we welcome the return of Linux Journal, it’s worth recognizing the impact of the September 22nd announcement of the magazine’s return and how it sparked many feelings of nostalgia and excitement in thousands among the Linux community. That being said, it is also worth noting that the ways in which journalism has changed since Linux Journal’s first publication in 1994. The number of printed magazines have significantly decreased and exclusively digitally published content has become the norm in most cases. Linux Journal experienced this change in 2011 when the print version of the magazine was discontinued. Although many resented the change, it is far from the only magazine that embraced this trend. Despite the bitterness by some, embracing the digital version of Linux Journal allowed for its writers and publishers to direct their focus on taking full advantage of what the internet had to offer. 

Despite several advantages of an online...

Many computers these days come with two hard drives, one SSD for fast boot speeds, and one that can be used for storage. My Dell G5 gaming laptop is a great example with a 128GB NAND SSD and a 1TB SSD. When building out a Linux installation I have a few options. Option 1: Follow the steps and install Ubuntu on one SSD hard drive for quick boot times and better speed performance when opening files or moving data. Then mounting the second drive and copying files to it when I want to backup files or need to move files off the first drive. Or, Option 2: install Ubuntu on an older hard drive with more storage but slower start up speeds and use the 128GB as a small mount point.

However, as most Linux users are aware, solid state drives are much faster, and files, folders, and drives on a Linux system all have mount points that can be setup with ease.

In this article we’ll go over how to install Ubuntu Linux with separate /root and /home directories on two separate drives – with root folder on the SSD and home folder on the 1TB hard drive. This allows me to leverage the boot times and speed of the...

Michael Tremer, maintainer of the IPFire project, announced IPFire 2.25 Core Update 147 today. This is the newest IPFire release since Core Update 146 on June 29th.

IPFire 2.25 Core Update 147 includes some important security updates including a newer version of Squid web proxy that has patched recent vulnerabilities.

Beyond security updates, IPFire 2.25 Core Update 147 adds support for additional hardware, as well as enhancing support for existing hardware because the new release ships with version 20200519 of the Linux firmware package.

IPFire 2.25 Core Update 147 also rectified a recurring issue relating to forwarding GRE connections.

In addition, the update improved IPFire on AWS configurations.

IPFire 2.25 Core Update 147 includes these updated packages: bind 9.11.20, dhcpcd 9.1.2, GnuTLS 3.6.14, gmp 6.2.0, iproute2 5.7.0, libassuan 2.5.3, libgcrypt 1.8.5, libgpg-error 1.38, OpenSSH 8.3p1, squidguard 1.6.0.

You can download IPFire 2.25 Core Update 147 here.

As of today, Linux Journal is back, and operating under the ownership of Slashdot Media.

As Linux enthusiasts and long-time fans of Linux Journal, we were disappointed to hear about Linux Journal closing its doors last year. It took some time, but fortunately we were able to get a deal done that allows us to keep Linux Journal alive now and indefinitely. It's important that amazing resources like Linux Journal never disappear.

If you're a former Linux Journal contributor or a Linux enthusiast that would like to get involved, please contact us and let us know the capacity in which you'd like to contribute. We're looking for people to cover Linux news, create Linux guides, and moderate the community and comments. We'd also appreciate any other ideas or feedback you might have. Right now, we don't have any immediate plans to resurrect the subscription/issue model, and will be publishing exclusively on LinuxJournal.com free of charge. Our immediate goal is to familiarize ourself with the Linux Journal website and ensure it doesn't ever get shut down again.

Many of you are probably already aware of...