Category: Linux

Links: Linux Fundamentals, Parts 1-4

Welcome to “Linux fundamentals,” ….. designed to prepare you for the Linux Professional Institute’s 101 exam. ….. By the end of this series of tutorials (eight in all), you’ll have the knowledge you need to become a Linux Systems Administrator and will be ready to attain an LPIC Level 1 certification from the Linux Professional Institute if you so choose.

Full articles here (source: funtoo linux):
Linux Fundamentals, Part 1
Linux Fundamentals, Part 2
Linux Fundamentals, Part 3
Linux Fundamentals, Part 4

Link: Linux Troubleshooting: How To Keep A Process Running After Putty Or SSH Session Closed?

Mostly, I use SSH command to connect to my remote server. Unfortunately, today the power is gone and the Ethernet hub is turned off, so my SSH session was lost. What do you do if an important task is going on after losing your SSH session? Here is the simple tool called Tmux to keep a process running  after the SSH or Putty session lost.

Full article here:
Linux Troubleshooting: How To Keep A Process Running After Putty Or SSH Session Closed? (Unixmen)

Link: 6 Cool Uses of Linux Live CDs

One of the good (or bad) things about Linux is that there are a lot of different distributions and almost all of them come in the form of live CDs. For the casual user, you might be wondering why in the world you need a live Linux CD when you have a functional operating system installed in your system. Here are some of the reasons why you should always have a Linux live media, and it might even save your computer’s life.

Full article here:
6 Cool Uses of Linux Live CDs (Make Tech Easier)

Link: Understanding Linux File Permissions

The Unix operating system (and likewise, Linux) differs from other computing environments in that it is not only amultitasking system but it is also a multi-user system as well.

…..

In order to make this practical, a method had to be devised to protect the users from each other. After all, you could not allow the actions of one user to crash the computer, nor could you allow one user to interfere with the files belonging to another user.

This lesson will cover the following commands:

  • chmod – modify file access rights
  • su – temporarily become the superuser
  • chown – change file ownership
  • chgrp – change a file’s group ownership

Full article here:
Understanding Linux File Permissions (Project: Fenix)

Link: 5 Grep Tools for Linux

As every Linux user surely knows, grep is a reliable command-line tool for in-depth file searching. Still, many beginners avoid it because they dislike the terminal. The apps presented in this article aren’t exactly alternatives to grep because in some usage scenarios grep is truly irreplaceable. Instead, let’s call them visual upgrades for grep because they extend grep’s functionality and wrap it in a full-fledged graphical interface.

Full article here:
5 Grep Tools for Linux (Make Tech Easier)

Link: Security in Three Ds: Detect, Decide and Deny (using DenyHosts to stop brute-force SSH attacks)

Whenever a server is accessible via the Internet, it’s a safe bet that hackers will be trying to access it. Just look at the SSH logs for any server you use, and you’ll surely find lots of “authentication failure” lines, originating from IPs that have nothing to do with you or your business. Brute-force attempts (such as “dictionary attacks”) try different passwords over and over to try to get into your box, and there’s always a chance that they eventually will succeed. Thus, it’s a good idea to apply these “three Ds” for your security: detect intruder attempts, decide when they’ve gone “over the top” (past what would be acceptable for honest-to-goodness typing mistakes), and deny them access at least for a (longish!) while.

Several tools manage this kind of monitoring (see the Resources section). In this article, I describe installing, configuring and running DenyHosts. With it, you’ll have a running background dæmon that will check your system continuously for access attempts, decide if they look unsafe, block them and inform you. DenyHosts even can be configured to share information with other servers, so whenever a hacker is detected on one system, it will be blocked on other systems too.

Full article here:
Security in Three Ds: Detect, Decide and Deny (Linux Journal)

Link: How To Install And Configure Squid Proxy On Ubuntu And Debian

Squid Proxy is  a a great proxy server mainly used for caching frequently requested web content in order to speed up response time and also save network bandwidth. It supports many different protocols such as HTTP, FTP, TLS, SSL, Internet Gopher and HTTPS. Although it was originally designed to run as a daemon on Unix-like systems there have been several ports to windows, but according to wikipedia more current versions are not being developed.

Squid Proxy is released under the GNU General Public License.

In this tutorial you will learn how to install and setup Squid Proxy on Ubuntu and Debian Linux distributions. Just follow each step of this guide carefully and everything will be ok.

Full article here:
How To Install And Configure Squid Proxy On Ubuntu And Debian (Unixmen)

Link: The Difference Between Window Managers and Desktop Environments

Curious about what the differences between window managers and desktop environments are? Say no more!

In this article, I’ll go over what a window manager is, as well as what a desktop environment is. I’ll talk about the pros and cons of each to better help you decide which one is right for you!

Full article here:
The Difference Between Window Managers and Desktop Environments (Make Tech Easier)

Link: How to access Gmail from the command line on Linux with Alpine

If you are a command-line lover, I am sure that you welcome with open arms any tool that allows you to perform at least one of your daily tasks using that powerful work environment, e.g., from scheduling appointments and managing finances to accessing Facebook and Twitter.

In this post I will show you yet another pretty neat use case of Linux command-line: accessing Google’s Gmail service. To do so, we are going to use Alpine, a versatile ncurses-based, command-line email client (not to be confused with Alpine Linux). We will configure Gmail’s IMAP and SMTP settings in Alpine to receive and send email messages via Google mail servers in a terminal environment. At the end of this tutorial, you will realize that it will only take a few minimum steps to use any other mail servers in Alpine.

Granted there are already outstanding GUI-based email clients such as Thunderbird, Evolution or even web interface. So why would anyone be interested in using a command-line email client to access Gmail? The answer is simple. You need to get something done quickly and want to avoid using system resources unnecessarily. Or you are accessing a minimal headless server that does not have the X server installed. Or the X server on your desktop crashed, and you need to send emails urgently before fixing it. In all these situations Alpine can come in handy and get you going in no time.

Some of us older folks may remember that one of the first command-line based email programs was named Pine.  Wonder if the creators of this program had that one in mind when they chose the name?

Full article here:
How to access Gmail from the command line on Linux with Alpine (Xmodulo)