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

iwconfig - Linux command to configure a wireless network interface

Iwconfig  is  similar  to ifconfig(8), but is dedicated to the wireless interfaces. It is used to set the parameters of the  network  interface which  are  specific  to the wireless operation (for example : the fre‐quency).  Iwconfig may also be used to display  those  parameters,  and the wireless statistics (extracted from /proc/net/wireless).

All  these  parameters and statistics are device dependent. Each driver will provide only some of them depending on hardware support,  and  the range of values may change. Please refer to the man page of each device for details.