System Administration & Configuration

How to Convert to and From MP3 on Linux

MP3 is still easily the most widly used and widely supported digital audio file format. As a result, working with MP3 tends to be simple, especially on Linux. There was a time when it was still a proprietary format, and required additional packages, but now, converting your MP3 files is a breeze. In this tutorial you will learn: How to Install SoundConverter How to Convert To MP3 How to Convert From MP3
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Hard drive shredding on Linux

When we delete a file from a filesystem, the data is not physically removed: the operating system simply marks the area previously occupied by the file, as free and makes it available to store new information. The only way to make sure data is actually removed from a device is to override it with other data. We may want to perform such operation for privacy reasons (maybe we plan to sell the device and we want to be sure the new owner cannot access our data), or maybe to prepare a device for...
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How to install and configure Dropbear on Linux

The dropbear suite provides both an ssh server and a client application (dbclient), and represents a light alternative to OpenSSH . Since it has a small footprint and uses system resources very well, it is generally used on embed devices, with limited memory and processing power (e.g routers or embed devices), where optimization is a key factor. It provides a lot features, like, for example, X11 forwarding , and it is fully compatible with the OpenSSH public key authentication. In this...
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How to recover deleted files with foremost on Linux

In this article we will talk about foremost , a very useful open source forensic utility which is able to recover deleted files using the technique called data carving . The utility was originally developed by the United States Air Force Office of Special Investigations, and is able to recover several file types (support for specific file types can be added by the user, via the configuration file). The program can also work on partition images produced by dd or similar tools. In this tutorial...
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How to create a simple encrypted Two-Way SSH tunnel

Why would you need to create a simple Two-Way SSH tunnel? In your Linux system administration job have you ever found your self in a situation in which you cannot SSH to a any of your servers/hosts that may be behind a firewall, NAT or otherwise obstructed from an easy access. In order to gain the access, you would need to reconfigure the firewall or create VPN which could be an enormous overhead just because you need to execute few commands from now and then. With Two-Way SSH tunnel you can...
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How to Convert Video Formats on Linux

There are a few ways to convert video files on Linux. If you're a fan of command line tools, check out our FFMPEG video conversion guide . This guide is going to focus on HandBrake, a powerful graphical video conversion tool to covert video from and to many formats such as MP4, AVI, WebM and many more. In this tutorial you will learn: How to Install HandBrake How to Use Video Conversion Profiles How to Convert a Video
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How to setup NRPE for client side monitoring

Nrpe, or Nagios Remote Plugin Executor, is the client side service of a monitoring setup. The monitoring server will send commands to the client, which listens passively when got no work to do. Upon incoming command, the nrpe checks it's local configuration, and executes the plugin configured with the command, then sends back the results to the server for processing. You can read more about the server side installation in the Nagios installation guide , while this guide will focus on the...
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How to build a docker image using a Dockerfile

Docker skills are high in demand mainly because, thanks to the Docker we can automate the deployment of applications inside so-called containers , creating tailored environments that can be easily replicated anywhere the Docker technology is supported. In this tutorial we will see how to create a Docker image from scratch, using a Dockerfile . We will learn the most important instructions we can use to customize our image, how to build the image, and how to run containers based on it. In this...
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Restore pfsense configuration backup from console using USB drive

This article will describe a process on how to restore pfsense configuration backup from console using USB drive. In this tutorial you will learn: How to identify USB drive on pfsense system How to mount USB drive/stick How to restore pfsense backup
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Most common custom SSH Configurations of the OpenSSH Server

The Openssh set of utilities let us create secure, encrypted connections between machines. In this tutorial we will take a look at some of the most useful options we can use to change the behavior of sshd , the Openssh daemon in order to make your Linux system administration job easier. In this article we assume the existence of an already running and accessible server. If you want to know more about Openssh installation, you can take a look at this article on how to install SSH server on...
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Install and Configure MySQL Workbench on Ubuntu Linux

MySQL workbench is a graphical application which let us manage data and perform administrative tasks on MySQL databases. In this tutorial we will see how to install the program on Ubuntu 18.04 (Bionic Beaver) and we will perform a brief tour of some of its most basic functionalities to make your Linux system administration job easier. In this tutorial you will learn: How to install and configure MySQL workbench How to create a schema and a table via MySQL workbench How to crate an E.R diagram...
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How to Stream Video From VLC

Most Linux users are at least familiar with VLC, and a good portion of them have it installed. What many don't know is that VLC can handle much more than just playing your videos. In addition to its many other options, VLC can easily stream a video over your network. In this tutorial you will learn: How to Set Up a VLC Stream How to Connect to a VLC Stream
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How to Save Space with Symlinks and Mount Points

When you're stuck with limited storage space, there's always the option of purchasing more storage, but what if you can't. Devices like Chromebooks and some laptops are fairly limited. Thankfully, Linux has a few tricks to help to make your Linux system administration job easier. Because Unix-like systems treat everything as a file, you can easily use symbolic links and mounted partitions to maximize space. In this tutorial you will learn: How to Use Symbolic Links at /home How to Use Symlinks...
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How dd command works in Linux with examples

Dd is a very powerful and useful utility available on Unix and Unix-like operating systems. As stated in its manual, its purpose is to convert and copy files. On Unix and Unix-like operating systems like Linux, almost everything is treated as a file, even block devices: this makes dd useful, among the other things, to clone disks or wipe data. The dd utility is available out of the box even in the most minimal installation of all distributions. In this tutorial we will see how to use it and...
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Executing commands on a remote machine from Java with JSch

SSH is an every-day tool of any Linux System Administration job . It is an easy and secure way to access remote machines on the network, transfer data and execute remote commands. Apart from interactive mode, there are many tools exist that enable automation of remote tasks that also rely on the existing ssh server/client architecture. For one such tool, you can read about ansible on Ubuntu for example. You can also find many implementations of the ssh client, but what about accessing the...
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How fstab works - introduction to the /etc/fstab file on Linux

The /etc/fstab file is one of the most important files in a Linux-based system, since it stores static information about filesystems, their mountpoints and mount options. In this tutorial we will learn to know its structure in details, and the syntax we can use to specify each entry in the file. In this tutorial you will learn: How to use the fstab file to provide static filesystem information How the fstab file is structured What is the purpose of each entry field in the file
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Check Linux Mint Version

There are number of ways on how to check Linux Mint version. Since Linux Mint comes with number of available Desktops the graphical user interface may differ from user to user hence the procedure is also different. From this reason the easiest and perhaps even recommend solution is to simply open up a command line terminal and execute the following command cat /etc/issue . To check a version of other Linux distributions visit our how to check Linux version guide. In this tutorial you will...
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Linux Filesystem Navigation Basics

This article explains basic commands for navigation within Linux file system. The diagram below represents (part of) a Linux file system know as Filesystem Hierarchy Standard. A line from one node to a node on its right indicates containment. For example, the student directory is contained within the home directory. In this tutorial you will learn: How to use pwd command How to use cd command How to navigate to user home directory Difference between relative vs absolute What is a parent...
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How to check Linux Version

The common scenario is that you have been given an access to a Linux system physically or via remote login and you have no idea what Linux version is installed on this particular system. Given that many of the today's Linux Distributions have implemented systemd as part of their core design, to check for a Linux version is in many cases relatively simple procedure. The simplest way to check Linux version is by using the hostnamectl command without any arguments. For example the below...
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How to setup AMule and control it via web interface on a Raspberry Pi

AMule is a p2p , open source client for the eD2k network. Released under the GPL license, it supports a lot of platforms and operating systems. In this tutorial we will see how to install a minimal, headless version of AMule on Raspbian "Stretch", the latest version of the official Raspberry Pi OS. We will see how to setup the amule-daemon and adjust the firewall rules in order to control it via web interface. In this tutorial you will learn: How to install and configure the amule-daemon How...
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