Adjusting the size of the virtual machine's hard disk

VirtualBox increase disk size on Linux

In this tutorial you will learn how to increase disk size on VirtualBox. One of the great things about installing an operating system into a virtual machine is that we can easily change the machine’s CPU utilization limit, its memory usage, and the amount of hard drive space it has. With VirtualBox, all of these hardware specifications can even be changed long after the virtual machine is created.

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How to use man Linux command

Man command in Linux with Examples

The Linux operating system is absolutely brimming with different commands to use. Even with a fresh Linux installation, you can open a command line terminal and have instant access to hundreds of commands. This is why we have man command in Linux.

There’s only one problem, which is that you need a little background information about how to use each command.

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NFS, SAMBA, and CIFS are three different terms that get thrown around a lot whenever someone mentions file sharing between two or more systems. But, do you know what these three implementations do, and how they do it differently from one another? For some reason these technologies remain in a shroud of mystery to even some seasoned system administrators.

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Connecting to a running Docker container via SSH on Linux

How to connect to Docker container via ssh

After installing Docker on Fedora, AlmaLinux, Manjaro, or some other distro, it’s time to install more containers. Once you have a Docker container up and running on a Linux system, one of the things you’ll likely need to do is run commands inside the container. This allows you to use the container similarly to how you would a physical machine, except that Docker has done most of the setup legwork for us already.

There are already two commands available that allow us to run commands on a Docker container. The first one is docker exec, and the second command, which allows us to attach to a running container, is docker attach. These commands usually suffice, but you may find yourself in a scenario where you’d prefer to use SSH to connect to the Docker container and manage it.

Not all Docker containers are provisioned to run SSH. Normally, Docker containers are very lightweight and only programmed to do one thing. However, some Docker containers will allow SSH, and this can make management of the container much easier. In this guide, we’ll see how to connect to a Docker container via SSH from the host system on Linux command line.

In this tutorial you will learn:

  • How to connect to a running Docker container via SSH

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Password expiration and history information on Linux

Linux – Reset password expiration, age and history

User management is an important part of Linux administration, so it’s essential to know about all the user accounts on a Linux system. Some common user administration tasks are to list users, disable a user account, or create and modify user accounts.

In this guide, we will be focusing on managing user passwords. It’s good security practice to force users to change their password every once in a while by setting passwords to expire. In the examples below, you’ll see how to reset a user’s password, set their password to expire (either instantly or in the future), and see the age of a user’s password. We’ll also see how password changes can be seen in log files, giving us some insight into user’s password change history.

In this tutorial you will learn:

  • How to set a user’s password to expire
  • How to see the age of a user’s password
  • How to see password changes in log files

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Configuring Squid proxy on Linux

Squid proxy configuration tutorial on Linux

Squid is a robust proxy server that supports caching for protocols like HTTP, HTTPS, and FTP. It has the ability to speed up web requests by caching frequently accessed websites, and serving that cache to requesting clients. This is a great way for networks to reduce bandwidth consumption and provide snappier response times for web browsing.

In this guide, we’ll go over the step by step instructions to download, install, and configure Squid proxy on a Linux system. Follow along with us to get it setup on your own system, which can either provide caching just for yourself or all the way up to an entire organization of computers.

In this tutorial you will learn:

  • How to download and install Squid proxy on major Linux distros
  • How to configure Squid proxy
  • How to configure a browser to use Squid proxy

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Renaming multiple files at once on Linux

How to rename multiple files on Linux

Renaming files on Linux systems is usually handled by the mv (move) command. The syntax is just mv old.txt new.txt. Simple enough, but what if we have multiple files that need to be renamed at once, even hundreds of them? The default mv utility can’t handle renaming more than one file unless we do a bit of scripting. There are also other utilities we can install to solve the problem, like rename and mmv.

In this guide, we’ll show you how to use the mv command as well as the rename and mmv tools to rename multiple files on your Linux distro. We’ll go over several examples so you can understand the syntax and how to use each method.

In this tutorial you will learn:

  • How to rename multiple files at once with mv command
  • How to install rename on major Linux distros
  • How to install mmv on major Linux distros
  • How to use mmv, through command examples
  • How to use rename, through command examples

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Listing installed packages with apt package manager

How to list installed packages with apt command on Linux

One of the most attractive features of running a Linux system is the instant access to thousands of packages that are able to be installed from the Linux distro’s package manager.

The apt package manager does a lot more than just install packages. One example is using apt to search for packages to install. In this guide, we’ll see how to list installed packages with apt. This will only work in Linux distros that use the apt package manager, such as Debian, Ubuntu, and Linux Mint just to name a few.

In this tutorial you will learn:

  • How to list installed packages with apt package manager

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Using dpkg command on Linux

Beginners guide to dpkg Linux command

Debian Linux and other Debian based Linux distributions, such as Ubuntu and Linux Mint, use dpkg as a package manager.

You might be thinking, “I thought those distributions used apt – that’s what I always use to install packages.” That’s true, apt is also a package manager, but really it’s just passing off tasks to dpkg in the background. apt and other package managers on Debian usually just utilize dpkg to install packages or perform similar tasks.

Package manager commands like those from apt or apt-get are meant for end-users. They’re easy to use and are very familiar to most Linux users. dpkg is low-level tool that is more geared towards use by the system, but we can still use it with the dpkg command.

In this guide, we’ll go over various dpkg command examples to help you learn to use the tool and manage packages on your Debian or Debian based system.

In this tutorial you will learn:

  • How to install .deb packages with dpkg
  • How to use dpkg command through examples

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Saving and exiting a file in nano editor

How to save and exit file using nano editor in Linux

The nano editor is one of the most popular ways to edit files via the command line on Linux systems. There are plenty of others, like vim and emacs, but nano is praised for its ease of use.

Despite being one of the easier to use text editors, it can still be confusing the first time you open it, especially if you’re used to GUI applications. In this guide, we’ll go over the step by step instructions to save and exit a file in nano. This is one of the most common and recurring tasks you’ll ever do with the text editor.

In this tutorial you will learn:

  • How to save and exit a file in nano editor

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Extracting tar file on Linux

How to extract tar file on Linux

The tar file type is used to combine multiple files into a single archive. Tar actually means “tape archive,” because tar’s original purpose was to be used on tape backups – that should tell you how old this format is. Linux systems still use the tar format, and it continues to enjoy widespread use to this day.

Tar files, with the extension .tar, are often called “tarballs.” These files will preserve the Linux file permissions and can combine any number of files into the single archive, but they don’t apply any compression or space savings. However, compression can be easily applied to the tar file, resulting in extensions like .tar.gz in the case of gzip compression, or .tar.xz for xz compression.

In this guide, we’ll show how to open tar files on command line and via GUI. This will include tar files with various compression applied to the archive. Check out the examples below to find out how.

In this tutorial you will learn:

  • How to open tar file via GUI
  • How to open tar file via command line

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Disabling SELinux on CentOS 8

How to disable SELinux on CentOS 8

SELinux, which stands for Security Enhanced Linux, is an extra layer of security control built into Red Hat Enterprise Linux and its derivative Linux distributions, such as CentOS. SELinux is enabled by default on CentOS 8, and would have to be manually disabled if a user doesn’t wish to use it.

Although SELinux can protect our system through access control for programs and system services, it’s not always necessary to have it enabled. Some users may even find that it interferes with certain programs they try to install. In this guide, we’ll go over the step by step instructions to disable SELinux on CentOS 8, both temporarily or persistently across reboots.

In this tutorial you will learn:

  • How to check the status of SELinux
  • How to put SELinux in permissive mode
  • How to disable SELinux

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