Removing a password from a PDF document in Linux

How to remove protection password from pdf document

If you have a PDF document (or even a bunch of PDF documents) that are password protected, there’s a simple way to remove the password from the file in Linux. In this guide, we’ll show you how to install the qpdf tool on any Linux distro, which is a handy command line utility that can do a bunch of things to PDF documents.

The feature we’ll be covering is password removal. Keep reading to see how to remove a password from one or more PDF documents with a short and easy command.

NOTE
This article isn’t about hacking PDF documents. We are assuming you already know the password to a PDF document and simply wish to remove it. You can always add a new password to the document with the same tool. We’ll show you how.

In this tutorial you will learn:

  • How to install qpdf on major Linux distros
  • How to remove encryption from a PDF document with qpdf
  • How to password protect a PDF document

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Using CurlFtpFS to mount remote FTP directories on Linux

Mount remote ftp directory host locally into linux filesystem

Do you often access your ftp site to make some simple changes or to share some documents that you wish to be accessible from anywhere?

You can make access to your ftp resource easier with the CurlFtpFS Linux utility. This fantastic utility allows you to mount your ftp site to any directory within your Linux filesystem.

In this guide, we’ll go over the installation of CurlFtpFS on major Linux distros, then cover the step by step instructions to configure it.

In this tutorial you will learn:

  • How to install CurlFtpFS on major Linux distros
  • How to mount remote FTP directory using CurlFtpFS
  • How to mount an FTP directory automatically with /etc/fstab

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Configuring Gmail as a Sendmail relay on Linux

Configuring Gmail as a Sendmail email relay

Sendmail is email routing software that can allow Linux systems to send an email from the command line. This allows you to send email from your bash scripts, hosted website, or from command line using the mail command. Another example where you can utilize this setting is for notification purposes such as failed backups, etc.

In this guide, we’ll go over the step by step instructions to configure Gmail as a relay for the sendmail client on Linux. Note that Sendmail is just one of many utilities which can be configured to rely on a Gmail account. Others that are capable of this include postfix, exim, ssmpt, etc. The instructions here should work for any mainstream Linux distribution.

In this tutorial you will learn:

  • Gmail configuration prerequisites
  • How to install Sendmail and mail utilities on Linux
  • How to configure Gmail as a relay for Sendmail
  • How to test the config by sending an email from command line

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maim

How to take screenshots using maim on Linux

On Linux there are many utilities we can use to take screenshots. Every complete desktop environment, such as GNOME, KDE or XFCE has its integrated application specifically designed for this task, but many other small
desktop-independent programs exist. In this tutorial we talk about a very lightweight and versatile command-line application, maim (make image), and we see what are the many options we can use to modify its behavior.

In this tutorial you will learn:

  • How to install maim on the most used Linux distributions
  • How to take a screenshot of all the screen
  • How to save the screenshot in a specific format (png/jpg)
  • How to select a region of the screen interactively
  • How to take a screenshot of a window by passing its id to maim
  • How to take screenshots with a delay
  • How to use maim in a pipeline
maim

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Developing and running an Android app on a Linux system

Get Started with Android application development using Linux and Android SDK

Developers interested in the Android mobile operating system are able to use the Android SDK and various IDE software to code applications. These apps can then be made available and marketed to Android users around the world.

There are a lot of choices when it comes to programming Android applications. Your coding environment can involve a Linux system and a variety of different IDE programs to facilitate all of the software development. The trouble here is that each Linux distribution will often have a different set of requirements to run the sofware, and a separate list of steps that need to be followed.

In this guide, we’ll go through the step by step instructions to install Android Studio – which is one of the most popular Android IDEs – on a Linux system. This will work on any distribution because we’ll be using Snap package manager to manage the installation. Love it or hate it, the Snap package manager gets your system ready for Android development very quickly, by handling all the dependencies and working identically on any distribution you’re running, whether it be Ubuntu, Debian, Red Hat, CentOS, AlmaLinux, openSUSE, or any other type of Linux system.

Follow along with us below as we setup Snap package manager, install Android Studio, and then program a Hello World Android application to verify that everything is working properly.

In this tutorial you will learn:

  • How to setup Snap package manager
  • How to install Android Studio and SDK packages
  • How to create a Hello World test application
  • How to run an Android application on an emulated device

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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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VNC Remote-Screen Utilities for Linux

VNC Remote-Screen Utilities for Linux

If you manage more than one computer, you may have wanted, at one point or another, a “remote keyboard,” a “remote mouse,” and a “remote screen” for that far-away computer, even if it is just up or down the stairs in your house.

VNC (Virtual network computing) can help here. Think about it as your screen, a keyboard, and a mouse at a remote workstation, controlled via the network and quite usable in terms of speed, even on somewhat slower connections.

A VNC setup usually consists of two or more computers, where the computers which need to be remotely controlled run a server (the VNC server) and the clients which need to connect to it (with the possibility to do so simultaneously in many cases) running a client (the VNC client(s)).

In this tutorial, you will learn:

  • A list of the most prominent VNC utilities available for Linux
  • Which VNC server/client utility we like the best

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How to rip an audio CD from the command line using cdparanoia

How to rip an audio CD from the command line using cdparanoia

Nowadays we are surrounded by devices able to read digital audio, and there are many services such as Spotify which allow to stream content legally. However if you like to buy music on physical support (compact disc), you may want to extract the audio tracks so they can be used on your smartphone or favorite device, or just for backup purposes. There are man tools on Linux which can be used to accomplish such task, but in the vast majority of cases they are just frontend to cdparanoia. In this tutorial we will learn how to use this tool.

In this tutorial you will learn:

  • How to install cdparanoia on the most used Linux distributions
  • How to retrieve drive information
  • How to rip all the audio tracks from a compact disc
  • How to rip specific tracks and/or a specific segment of a track
  • How to pipe the output of cdparanoia to tools like flac or lame to compress the audio tracks
How to rip an audio CD from the command line using cdparanoia

How to rip an audio CD from the command line using cdparanoia

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Using a hex editor to view binary file on Kali Linux

How to install and use Hex editor on Kali Linux

Once a program has been compiled, it’s tough to get a peek at the source code or to manipulate its behavior. But there is one thing we can do, which is to edit the hexadecimal values inside the binary files. This will sometimes reveal information about a file, or allow us to modify its behavior if we can edit the right bit.

A classic example is video game hacks. When playing a game, let’s say your character has a health value of 100. Chances are that a certain bit can be edited to make it 9999. This works more reliably in older, basic games, but it illustrates how hex editors can modify a compiled binary file.

In this guide, we’ll show how to install hex editors on Kali Linux, and give some examples so you can see how to use them on your own system.

In this tutorial you will learn:

  • List of hex editors for Kali
  • How to use hex editors on Kali

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Mediawiki easy deployment with Docker container

About

The automated build docker Mediawiki system (CMS) image “linuxconfig/mediawiki” can be used to instantly deploy Mediawiki on your docker hosts.

Configuration

The Mediawiki runs on Debian GNU/Linux system featuring Apache web server, MariaDB ( MySQL ), database and PHP5. A new docker container based on “linuxconfig/mediawiki” will expose port 80 which can be linked to the docker host port for an immediate Mediawiki web configuration/installation access.

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How to promote Mediawiki user with sysop and bureaucrat privileges

The following lines will describe a procedure on how to promote mediawiki user to sysop and bureaucrat role directly using MySQL database.

Access database

First, connect to your database using mysql client. Depending on your environment you can run something like:

$ mysql -u USER -p PASSWORD

Once you get to the MySQL command prompt select appropriate Mediawiki database. In the example below the database name is wiki:

mysql> use wiki                                                                                                      
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed

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