Stop Ubuntu going into suspended mode

Disable suspend

$ sudo systemctl mask sleep.target suspend.target hibernate.target hybrid-sleep.target
Created symlink /etc/systemd/system/sleep.target → /dev/null.
Created symlink /etc/systemd/system/suspend.target → /dev/null.
Created symlink /etc/systemd/system/hibernate.target → /dev/null.
Created symlink /etc/systemd/system/hybrid-sleep.target → /dev/null.

Re-enable suspend

sudo systemctl unmask sleep.target suspend.target hibernate.target hybrid-sleep.target

Install the arduino IDE
1. https://www.arduino.cc/en/Main/Software/
2. Select Linux 64 bit
3. Click Just Download

Unzip the downloaded file as below:
vbhadra@jupiter:~/Downloads$ tar -xf arduino-1.8.10-linux64.tar.xz

Run the arduino IDE
vbhadra@jupiter:~/Downloads$ cd arduino-1.8.10/
vbhadra@jupiter:~/Downloads/arduino-1.8.10$ ./arduino

Configure
1. Tools -> Board -> Board -> Arduino/Genuino Uno
Tools -> Port -> /dev/ttyACM0

Installing and uninstalling .zip user libraries in Arduino IDE
Install
Sketch -> Include Library -> Add .zip library
Uninstall
$ find ~/ -type d -iname Arduino
./Arduino
$ ls -la Arduino/
drwx—— 4 vbhadra vbhadra 4096 Oct 1 11:31 libraries
$ ls -la Arduino/libraries/
readme.txt xxxLPWA/ Vivek/

Remove the library folder you want to uninstall
$ sudo rm -rf Arduino/libraries/xxxLPWA/

Then modify your library code, create a .zip file and install it again.

Compile & verify the code
Sketch -> Verify & Compile
You should see “Done compiling”

Upload the code
Sketch -> Upload
You should see “Done Uploading”.

Troubleshooting
1. Issue 1:
An error occurred while uploading the sketchavrdude: ser_open(): can’t open device “/dev/ttyACM0”: Permission denied

-> Check if the port exist on the linux machine:

ls -l /dev/ttyACM*

-> Change the permission of the port as below:
sudo chmod a+rw /dev/ttyACM0

2. Junk characters in serial port

void setup()
{
  Serial.begin(9600);
  Serial.write("Hello World");
}

3. Mounting the SD card into the /mnt

mount -t vfat /dev/mmcsd0 /mnt

Install the custom Toolchain

Download and install the toolchain rpm

sudo alien ~/Downloads/<toolchain-name>.rpm

sudo dpkg -i ./<toolchain-name>.deb

Locate the arm compiler

sudo find / -iname arm-*-gnueabihf-g++ 2>/dev/null

/opt/toolchain/arm-cortexa9_neon-linux-gnueabihf-lh3/bin/arm-cortexa9_neon-linux-gnueabihf-g++

Settings

Go to the Projects Tab on the left pane.

Click on the Manage Kit buttons.

If you want use your custom compiler and debugger etc then you have to create a manual kit.

A kit is a set of tools like compiler, QtVersion (qmake), debugger, device etc.

Before you can create a manual kit, you have to create place holders for your custom compiler, debugger etc.

Kit

Qt Version

Go tot the Qt Version Tab and select manual. Then click on Add button.

Here we are trying to specify the qmake binary we are going to use for the project.

In my case my qmake is located (comes from installation of the toolchain) at the below location:

/opt/toolchain/arm-cortexa9_neon-linux-gnueabihf-lh3/bin/qmake.

So in the add wizard I navigate to the above location and select qmake binary.

Qt automatically detects it as Qt Version 5.11.2. In the Kit section we are going to refer to this in near future.

Compilers

Next we have to choose our own custom C++ compiler.

In my case my C++11 compiler is located (comes from the toolchain installation) at the below location

/opt/toolchain/arm-cortexa9_neon-linux-gnueabihf-lh3/bin/arm-cortexa9_neon-linux-gnueabihf-g++.

Now, click on the Manual → C++ and click the Add button to start adding your own custom g++ compiler to the list.

This will ask you to provide a name to the custom compiler, give a name, e.g. “G++ for ATOM”, any other string you like.

Put the absolute path of the g++ binary which you want to add under the Compiler path:

/opt/toolchain/arm-cortexa9_neon-linux-gnueabihf-lh3/bin/arm-cortexa9_neon-linux-gnueabihf-g++

In the ABI, select arm-linux-generic-elf-32bit, leave the rest as default.

Apply, ok. Now you have your custom compiler in the list.

Debuggers

Go to the debugger tab.

Click on the Manual and Add.

Provide a suitable name, “ATOM GDB for Cortex A9”.

Specify the absolute path in the Path.

/opt/toolchain/arm-cortexa9_neon-linux-gnueabihf-lh3/bin/arm-cortexa9_neon-linux-gnueabihf-gdb

Apply, Ok.

Devices

In the Devices specify the details of the device where you want to run your generated binaries.

Custom Kit

Now go back to the Kits tab.

Select Manual.

Click on Add.

Provide a name for your custom Kit, e.g. ATOM.

In the Device Type, select Generic Linux Device.

In Device, select your own device, e.g. Custom Atom Device.

Compiler: C++: select your own created compiler from the drop down list.

Debugger: select the one you created previously.

Qt Version: select your own Qt Version as created previously.

Additional build arguments

Under Build & Run on the left hand panel, select the Build Option.

This will show you a loads of option on the right hand pane.

For our project we need to set the environment variable PRODUCT=ATOM.

To add this, click on the Details button along side qmake command under Build & Run.

This will look like below:

In the Additional Argument section specify, PRODUCT=ATOM.

Now, save it and try compiling your code. Make sure you clean it before giving it a try.

I was trying to connect to a newly installed Ubuntu Linux version 12.04 using FileZilla but the application kept on timing out. This can happen either in either of the below two protocols:

FTP or SFTP.

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Check if sshd service is running in Ubuntu with the below command:

vbhadra@vbhadra-VirtualBox:~$ ps aux | grep ssh
vbhadra 1702 0.0 0.0 4088 204 ? Ss 11:49 0:00 /usr/bin/ssh-agent /usr/bin/dbus-launch --exit-with-session gnome-session --session=ubuntu
vbhadra 4358 0.0 0.0 4400 824 pts/3 S+ 14:10 0:00 grep --color=auto ssh
vbhadra@vbhadra-VirtualBox:~$ sudo netstat -natp | grep sshd
vbhadra@vbhadra-VirtualBox:~$ sudo netstat -natp | grep ssh
vbhadra@vbhadra-VirtualBox:~$

The above command and their output shows there is no sshd service running on my Ubuntu Linux.

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Source: Let me judge!

#include <iostream>
#include <sstream>
#include <stdio.h>
#include <string>

using namespace std;

template <typename T>
class Stack {
private:
    int top;
    T datastore[100];
public:
    Stack() : top(-1) {}
    bool is_stack_empty(void) {return (top == -1) ? true : false;}
    bool is_stack_full(void) {return (top >= 100) ? true : false;}
    void push(T elem)
    {
        if (!is_stack_full()) {
            top++;
            datastore[top] = elem;
        }
    }

    T pop()
    {
        if (is_stack_empty()) {
            cout << "Stack is empty" << endl;
        } else {
            int data = datastore[top];
            top--;
            return data;
        }
    }

    T peek(void)
    {
        if (is_stack_empty()) {
            cout << "Stack is empty" << endl;
        } else {
            int data = datastore[top];
            return data;
        }
    }
};

int main()
{
    Stack<int> s;
    int num;

    do {
        cout << "Enter a number ";
        cin >> num;
        cout << "Number entered is " << num << endl;
        while (num)
        {
            int n = num % 2;
            num = num/2;
            s.push(n);
        }

        cout << "The binary equivalent of the number is " << endl;
        while(!s.is_stack_empty()) {
            cout << s.pop();
        }
        cout << endl;
        cout << "Do you want to continue? (y/n) ";
        getchar();
    } while (getchar() == 'y');

    return 0;
}

#include <iostream>
#include <sstream>
#include <stdio.h>
#include <string>

using namespace std;

template <typename T>
class Stack {
private:
    int top;
    T datastore[100];
public:
    Stack() : top(-1) {}
    bool is_stack_empty(void) {return (top == -1) ? true : false;}
    bool is_stack_full(void) {return (top >= 100) ? true : false;}
    void push(T elem)
    {
        if (!is_stack_full()) {
            top++;
            datastore[top] = elem;
        }
    }

    T pop()
    {
        if (is_stack_empty()) {
            cout << "Stack is empty" << endl;
        } else {
            int data = datastore[top];
            top--;
            return data;
        }
    }

    T peek(void)
    {
        if (is_stack_empty()) {
            cout << "Stack is empty" << endl;
        } else {
            int data = datastore[top];
            return data;
        }
    }
};

int main()
{
    Stack<char> word;
    string str;
    string pali = "";

    cout << "Enter a word ";
    cin >> str;
    char w;
    for (auto i = 0; i < str.size(); ++i) {
        w = str[i];
        word.push(w);
    }
    while(!word.is_stack_empty()) {
        stringstream ss;
        char c = word.pop();
        ss << c;
        string s = ss.str();
        pali += s;
    }

    if (str == pali)
        cout << "The word is a palindrome " << endl;
    else
        cout << "The word is not a palindrome " << endl;


    return 0;
}

Let’s say I have a python script called my_module.py in the location ~/junk/my_test/script/lib/. The my_module.py has a very trivial function called my_print() which just prints “Hello World”.

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Using gdb to user space program
vbhadra@ubuntu:~$ sudo gdb ./netlinkUser
[sudo] password for vbhadra:
GNU gdb (Ubuntu 7.9-1ubuntu1) 7.9
Copyright (C) 2015 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html&gt;

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It is a myth being spread across by media that #AAP is sweeping the support of the people all across the country to garner more support in future in favour of it for some vested interest or over enthusiasm. But step back and think for a moment, Delhi was the epitome of #AAP movement, it gained its acme of campaign with all those rhetorical promises, by all those theatrics of cutting the electrical wires, burning bill in public. Populism at its best. But even after all these melodrama it couldn’t even stand as the the single largest party which it claimed to be before the election. It reminds me somewhat of the “Singur” moment in West Bengal by Mamta Banerjee. But the difference is that Mamta Banerjee (for good or bad) was able to sweep whole of Bengal, there was no sign of others around, people truly gave their mandate. But here is a party which claims to be the party with a difference (the difference is yet to come out in their practice) has not even managed to be the single largest party in a small/half state like Delhi. And I believe #AAP had a better popular plank for campaign than Mamta Banerjee. So the first impact of #AAP is not even the half of Trinomool Congress.
Now just after the election #AAP has compromised with its basic promise of not aligning with any of the “Chor”/”Bhrasth” (as they say) national parties. But they have already shook hands with Congress. Some would argue on a super technical theorem that this is not an alliance it is a support etc. But think about the support of Mulayam to Congress, that’s exactly the same, supporting from outside and not an alliance. But there is always a quid-pro-quo – Mulayam provides support to a minority govt and in turn centre doesn’t let the CBI go after him and his party leaders, centre turns a blind eye to the riots happening in the state so on and so forth. Now here in Delhi Congress’s immediate target is to defend Modi, cut into anti-congress vote and restrict him to come to power. And once that is accomplished congress can collect a bunch of so called secular parties and form the next govt. And then after what would it demand from #AAP in future that future will tell us, I have no idea. Congress support to a minority govt has been usually maximum 2 years so far. As I strongly believe there is no free lunch this has to be a part of a grand deal, time will tell.
Now coming back to #AAP garnering support across the country. So a new party with some holier than thou agenda’s, with some populist schemes in the list couldn’t even manage to totally woo the already distressed people of a very small state. And after forming the govt the way they have tried to keep their promises so far gives us two points, one they are following the standard populist measures to woo the voters(free water and 50% electricity bill reduction etc) and two that these people are modern day leftists when it comes to economy. I see a lot of people who perhaps voted for them are not happy and have already started raising their voice. So here #AAP in fact loses their voters share rather than extending it. One more point, a percentage of people who voted for AAP in Delhi thinks they want Modi as their next PM in the LS election. So #AAP loses this section of voters too when it comes to LS. The third is interesting. I see a lot of #AAP supporters are pathological Modi haters. A lot of new #AAP supporters would be bad mouthing about Modi all the time, which indicates they are the original Congress supporters and now turning to #AAP as Congress is nowhere in the picture. This section of voters are interesting because rather than cutting into Modi’s vote (which is Congress’s original plan for supporting #AAP) it seems that #AAP is now cutting into Congress’s traditional vote bank. That be the case it is going to help Mr. Modi in coming days than hurting him. It would be difficult for #AAP to translate all their dramatic campaigns in the national platform simply because state to state India is different and they would realise it soon. They would find it extremely difficult follow what they preach as lots of those are just not practical. Unlike Modi #AAP doesn’t have any track records to showcase to the people as their model of governance. The little they have shown has party gone against them already, at least to a section of voter. So however much the media may try to make the king of their choice, at last the the real people’s king would perhaps have the last laugh. Jai Hind!!

It’s been a new challenge, a new fresh energy was required and I am putting all into my new assignment. It’s been two weeks now and it’s all fine. Looking forward to excel in coming assignments. Feeling all set for taking up fresh new dimension into the whole aspect.

Extremely missing my family. Haven’t cuddled my little baby for around nine months in a row now. Can’t just wait anymore but still couple of months to go, can’t just help it. The recent currency dilemma is playing bad for my family’s visa. Keeping fingers crossed.
Cheers!

Starting off my career as an Independent Embedded Systems Consultant from 19th. Excited, thrilled but cautious about it.