Install PyQt6 on Linux

To install PyQt6 for Python 3 on Linux (Tested on Ubuntu 21.10 over VirtualBox):

$ pip3 install PyQt6

Install wxPython on Linux Mint 20.2

To install wxPython on Linux Mint 20.2, for Python 3, enter the command in Terminal:

pip3 install -U \
    -f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/ubuntu-20.04 \
    wxPython

Tested on Linux Mint 20.2 xfce, run on VirtualBox 6.1.

ref:

~ https://wxpython.org/pages/downloads/index.html

Install dfu-util on Raspberry Pi

dfu-util is a host side implementation of the DFU 1.0 and DFU 1.1 specifications of the USB forum. DFU is intended to download and upload firmware to/from devices connected over USB. It ranges from small devices like micro-controller boards to mobile phones. Using dfu-util you can download firmware to your DFU-enabled device or upload firmware from it. 

See the manual page for examples of use.

To install dfu-util on Raspberry Pi, enter the command in Terminal:

$ sudo apt install dfu-util

Install Python 2 and pip on Ubuntu 20.04

To install Python 2 on Ubuntu 20.04:

$ sudo apt install python

or

$ sudo apt install python2

python-pip may be no exists anymore in 20.04, and looks like it has been removed from the repositorie.

To install pip for Python :

$ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
$ sudo python2 get-pip.py

If you run "python2 get-pip.py" without sudo, you have to set PATH after installed.

The world's fastest supercomputer, Sunway-TaihuLight by China, run Linux

Sunway-TaihuLight, a new-generation supercomputer installed in the east China city of Wuxi, is able to perform quadrillions of calculations per second. The system was named the world's fastest computer during the Int'l Supercomputing Conference in Frankfurt.

Install oracle-java8 on Ubuntu with ppa:webupd8team/java

To install oracle-java8 on Ubuntu 16.04:

- add ppa:webupd8team/java to your repository

$ sudo add-apt-repository ppa:webupd8team/java

- update with

$ sudo apt update

- install oracle java8

$ sudo apt install oracle-java8-installer

Install OpenShot Video Editor on Ubuntu

OpenShot Video Editor is a free, open-source video editor for Linux licensed under the GPL version 3.0.

OpenShot can take your videos, photos, and music files and help you create the film you have always dreamed of. Easily add sub-titles, transitions, and effects, and then export your film to DVD, YouTube, Vimeo, Xbox 360, and many other common formats.

To install OpenShot on Ubuntu using PPA, run the commands on Terminal:
$ sudo add-apt-repository ppa:openshot.developers/ppa
$ sudo apt-get update
$ sudo apt-get install openshot-qt

Check if your Linux kernel is running in 32bit or 64bit

Run the command to check if your Linux kernel is running in 32bit or 64bit:

$ getconf LONG_BIT

MonoDevelop/C#: get the current running Common Language Runtime verion, with the Environment.Version property.

Read the Environment.Version Property to gets a Version object that describes the major, minor, build, and revision numbers of the common language runtime.

For the .NET Framework Versions 4, 4.5, 4.5.1, and 4.5.2, the Environment.Version property returns a Version object whose string representation has the form 4.0.30319.xxxxx. For the .NET Framework 4.6, it has the form 4.0.30319.42000.

Example:

using System;

namespace HelloWorldCsharp
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            Console.WriteLine ("Hello World!");

            /*
             * For the .NET Framework Versions 4, 4.5, 4.5.1, and 4.5.2, 
             * the Environment.Version property returns a Version object whose 
             * string representation has the form 4.0.30319.xxxxx. 
             * 
             * For the .NET Framework 4.6, it has the form 4.0.30319.42000.
             * 
             * ref: https://msdn.microsoft.com/en-us/library/system.environment.version(v=vs.110).aspx
            */
            Console.WriteLine("Version: \t" + Environment.Version.ToString());
            Console.WriteLine("(Major): \t" + Environment.Version.Major.ToString());
            Console.WriteLine("(Minor): \t" + Environment.Version.Minor.ToString());

            Console.WriteLine("Press any key to exit.");
            Console.ReadKey();
        }
    }
}

MonoDevelop/C# to keep console open with ReadKey()

In C# console program, we can keep console open by inserting the code Console.ReadKey():

using System;

namespace HelloWorldCsharp
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            Console.WriteLine ("Hello World!");
            Console.WriteLine("Press any key to exit.");
            Console.ReadKey();
        }
    }
}

MonoDevelop on Kubuntu: Hello World C# example

using System;

namespace HelloWorldCsharp
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            Console.WriteLine ("Hello World!");
        }
    }
}

Create a Hello World C# example in MonoDevelop run on Kubuntu:

Install MonoDevelop on Kubuntu 15.10 with Muon Discover Software Center

MonoDevelop enables developers to quickly write desktop and web applications on Linux, Windows and Mac OS X. It also makes it easy for developers to port .NET applications created with Visual Studio to Linux and Mac OS X maintaining a single code base for all platforms.

It can be installed on Kubuntu with Muon Discover Software Center. But the current installed version is 5.5, not the current latest version of 5.9.7.

Install MonoDevelop on Kubuntu 15.10 (run on VirtualBox) with Muon Discover Software Center, and create Hello World Project of Gtk# 2.0.

Install Qt on Kubuntu 15.10/VirtualBox

This video show how to install Qt/Qt Creator on Kubuntu 15.10 running on Oracle VirtualBox:

Install KDevelop on Kubuntu 15.10/VirtualBox, using Muon Discover Software Center

This video show how to install KDevelop on Kubuntu 15.10/VirtualBox, using Muon Discover Software Center:

Install Qt/Qt Creator on Ubuntu 15.10

To download Qt, visit Qt Download page.

Remark:
- In my case of installing on Ubuntu 15.10 running on VirtualBox, have to disable VirtualBox's 3D Acceleration.
- build-essential and libgl1-mesa-dev are needed, install with comand:
sudo apt-get install build-essential libgl1-mesa-dev

This video show the steps to download and install Qt/Qt Creator on Ubuntu 15.10:

Install KDevelop on Ubuntu 15.10, using Ubuntu Software Center

KDevelop is an easy to use integrated development environment for KDE. It supports a wide range of programming languages and features project management, an advanced editor, a class browser and an integrated debugger.

The application wizard can generate fully functional projects for terminal programs and GUI programs using Qt, KDE or GNOME.

https://www.kdevelop.org/

It can be installed using Ubuntu Software Center.



Hello World KDevelop

Get screen resolution using command line

To get screen resolution using command line, for Ubuntu Linux:
$ xdpyinfo  | grep dimensions

or

$ xrandr -q

How to prevent dialog "Enter password for keyring Default keyring to unlock" always pop-up

To prevent the dialog "Enter password for keyring 'Default keyring' to unlock" always pop-up, you can assign a blank password to keyring.

Be careful - 
By choosing to use a blank password, your stored passwords will not be safely encrypted. They will be accessible by anyone with access to your files.

Run Setting - Passwords and Keys

Right click "Default keyring" and "Change Password"

Enter old password

Leave blank in new password

nproc - check the number of processing units available

The Linux command nproc print the number of processing units available to the current process, which may be less than the number of online processors.

Dump detailed CPU information with cpuid

cpuid dump detailed information about the CPU(s) gathered from the CPUID instruction,
and also determine the exact model of CPU(s).


To install cpuid:
$ sudo apt-get install cpuid