Transferring files over SSH - SCP command

If copying on the command line, use:




AUTHOR: OBSCURE

How to launch a GUI app via the Terminal and close the Terminal without exiting the app?

Type in The Terminal, program_name & and then press Ctrl+d.


AUTHOR: OBSCURE

Enable Hibernate in Ubuntu 12.04

In Ubuntu 12.04 and newer, hibernation has been disabled by default in policykit. To enable hibernation, you can follow official documentation here.

 Before enabling hibernation, please try to test whether it works correctly by running pm-hibernate in a terminal. The system will try to hibernate. If you are able to start the system again then you are more or less safe to add an override.

To do so, start editing:

sudo gedit /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla

Paste the following lines:

[Re-enable hibernate by default]
Identity=unix-user:*
Action=org.freedesktop.upower.hibernate
ResultActive=yes

Save and exit gedit.

Restart and hibernation is back!

Or run the following code to just reset the menu:

killall unity-panel-service

Source: How to enable hibernation?

AUTHOR: OBSCURE

Serial Port Communication From Java - RxTx Installation.

Want to communicate with serial port using Java? You may want to try RxTx library. It's easy to use.
To install follow the instruction below:

The official RxTx binary pack is available here. The provided link will download the distro with some standard binaries (for linux 32bit, 64 bit, etc). If binaries for your specific operating system are not included, you may consider recompiling RxTx yourselves.

For a custom Win64 RxTx distro, have a look at the CloudHopper's web site.

To install it, unzip the distribution file in a temporary place and do the following copies:

• File RXTXcomm.jar should go under JDKDIR/jre/lib/ext/
• The necessary library( .so for linux, .dll for windows) should go under JDKDIR/jre/bin/

AUTHOR: OBSCURE

Ambiguity problem in C++

Functions with predefined value can cause ambiguity in C++. See the example below:


If I call this like this, the first call is ok, but the second call give the ambiguous function error.




AUTHOR:

OBSCURE

PYTHON REFERENCES

1. Online Python Tutor : It is a free educational tool that helps students overcome a fundamental barrier to learning programming: understanding what happens as the computer executes each line of a program's source code. Using this tool, a teacher or student can write a Python program directly in the web browser and visualize what the computer is doing step-by-step as it executes the program.
2. life is short - you need Python!: A blog on Python with tutorials, code, programs, tips and tricks, how-to, book-list, crawler / spider help, data structure and algorithm implementation and many more ... maintained by Tamim Shahriar Subeen, one of the best IT professional in Bangladesh.
3. Python for fun - advanced python codes: This collection is a presentation of several small Python programs. They are aimed at intermediate programmers; people who have studied Python and are fairly comfortable with basic recursion and object oriented techniques. Each program is very short, never more than a couple of pages and accompanied with a write-up.
4. site aims to be both a library of educational materials using Python to teach computer programming, and a virtual meeting place for teachers and students engaged in learning and teaching using Python.  Happy computing!

Turtle

Turtle is a Python module to draw pictures.

import turtle # allows us to use the turtles library
wn = turtle.Screen() # creates a graphics window
alex = turtle.Turtle() # create a turtle named alex
alex.forward(150) # tell alex to move forward by 150 units
alex.left(90) # turn by 90 degrees
alex.forward(75) # complete the second side of a rectangle
wn.exitonclick()

Sending SMS via USB Connected Cell Phone with Python

import serial
import time
class SMSsender:
    def __init__(self):
        self.destination = ""
        self.msg = ""

    def setRecipient(self, dest):
        self.destination = dest

    def setContent(self, message):
        self.msg = message

    def connectPhone(self):
        #replace '/dev/ttyACM0' with your device name
        #replace 460800 with a suitable baud-rate of your phone 
        self.ser = serial.Serial('/dev/ttyACM0', 460800, timeout=2)
        time.sleep(1)

    def sendMessage(self):
        self.ser.write('ATZ\r')
        time.sleep(1)
        self.ser.write('AT+CMGF=1\r')
        time.sleep(1)
        self.ser.write('''AT+CMGS="''' + self.recipient + '''"\r''')
        time.sleep(1)
        self.ser.write(self.content + "\r")
        time.sleep(1)
        self.ser.write(chr(26))
        time.sleep(1)

    def disconnectPhone(self):
        self.ser.close()

To send sms use this follow the code below:

sms = SMSsender()
sms.setRecipient('+8801*********')
sms.setContent('Write your message here')
sms.connectPhone()
sms.sendMessage()
sms.disconnectPhone()

You may also try this link(I've not tested yet): sms-over-3g-and-bluetooth-from-python
Source: linux-101.org

Adding a Syntax Highlighter to your Blogger blog

Adding a Syntax Highlighter to your Blogger blog.

Make them all glow, can you?

Instructions:
 Click on orbs arranged in a grid to make them all glow. Clicking on an orb 
changes its state from unlit to lit or lit to unlit along with the 
neighboring orbs. Turn on all the orbs to pass a level with as few moves 
as you can. There are 9 levels, each with more orbs than the previous one.
Two difficulty modes. In the easy mode, all orbs are unlit in the beginning 
and in the hard mode, some orbs are already lit to make things difficult 
for the player.
Author:
MUKTO SOFTWARE LTD.

Python - Coding with fun

How to reverse a string?

s = 'abcdef'
s = s[::-1]
print s 

Explanation: "::" is known as stride notation

s[::2]
s[::-2]

Returns "ace" and "fdb" respectively.

How to read from console in Python?

name = raw_input()

Want to read an integer?

num = raw_input()
num = int(num) # raw_input returns string, so convert it to integer

Swap values in python:

a, b = b, a

My motivation to learn python is: life is short - you need Python

Installing Apache Maven-Java tool

Download maven.

Windows OS:

1. Unzip the distribution archive, i.e. apache-maven-3.0.4-bin.zip to the directory you wish to install Maven 3.0.4. These instructions assume you chose C:\Program Files\Apache Software Foundation. The subdirectory apache-maven-3.0.4 will be created from the archive.
2. Add the M2_HOME environment variable. [almost similar as this]: adding the M2_HOME variable in the system variables with the value                                                                                      C:\Program Files\Apache Software Foundation\apache-maven-3.0.4. Be sure to omit any quotation marks around the path even if it contains spaces.
3. In the same dialog, add the M2 environment variable in the system variables with the value %M2_HOME%\bin.
4. In the same dialog, update/create the Path environment variable in the system variables and prepend the value %M2% to add Maven available in the command line.
5. In the same dialog, make sure that JAVA_HOME exists in your system variables and it is set to the location of your JDK, e.g.C:\Program Files\Java\jdk1.5.0_02 and that %JAVA_HOME%\bin is in your Path environment variable.
6. Open a new command prompt and run mvn --version to verify that it is correctly installed.

Linux based/Ubuntu Operating Systems:

1. Extract the distribution archive, to the directory you wish to install Maven 3.0.4. These instructions assume you chose /home/username/java/tools/maven.
2. Open terminal and type:  gedit ~/.bashrc
3. Set environment variable by adding the following lines at the bottom of .bashrc :
   
   •  export M2_HOME=/home/username/java/tools/maven
   • export M2=$M2_HOME/bin
   • export PATH=$M2:$PATH
   • export JAVA_HOME=/usr/lib/jvm/jdk-default #if JAVA_HOME not exist.
4. Run mvn --version to verify that it is correctly installed.

Send and receive SMS using GSM modem or phone on Ubuntu | TechyTalk.info

Send and receive SMS using GSM modem or phone on Ubuntu | TechyTalk.info.

#go to terminal and give the msg as below
#sudo python sms.py 'CellNumber Msg you want to send'
import gammu
import sys

def main():
    words = sys.argv[1].split(None, 1)
    dest = words[0]
    msg = words[1]
    print msg + "-----" + dest
    #return

    sms = gammu.StateMachine()
    sms.ReadConfig()
    sms.Init()

    message = {
        'Text': msg,
        'SMSC': {'Location': 1},
        'Number': destinationNumber,
    }
    print sms.SendSMS(message)

if  __name__ =='__main__':
    main()

How to create non-editable JTable:

Override the method "isCellEditable" and implement as needed, such as:

//instance table model
DefaultTableModel tableModel = new DefaultTableModel(){
    @Override
    public boolean isCellEditable(int row, int column) {
        return false;
    }
};
//...other codes
table.setModel(tableModel);

System.getProperty(key) key list for Java with value:

java system get property, private link.

System.getProperty(key) key list for JAVA:

java.version	Java Runtime Environment version
java.vendor	Java Runtime Environment vendor
java.vendor.url	Java vendor URL
java.home	Java installation directory
java.vm.specification.version	Java Virtual Machine specification version
java.vm.specification.vendor	Java Virtual Machine specification vendor
java.vm.specification.name	Java Virtual Machine specification name
java.vm.version	Java Virtual Machine implementation version
java.vm.vendor	Java Virtual Machine implementation vendor
java.vm.name	Java Virtual Machine implementation name
java.specification.version	Java Runtime Environment specification version
java.specification.vendor	Java Runtime Environment specification vendor
java.specification.name	Java Runtime Environment specification name
java.class.version	Java class format version number
java.class.path	Java class path
java.library.path	List of paths to search when loading libraries
java.io.tmpdir	Default temp file path
java.compiler	Name of JIT compiler to use
java.ext.dirs	Path of extension directory or directories
os.name	Operating system name
os.arch	Operating system architecture
os.version	Operating system version
file.separator	File separator ("/" on UNIX)
path.separator	Path separator (":" on UNIX)
line.separator	Line separator ("\n" on UNIX)
user.name	User's account name
user.home	User's home directory
user.dir	User's current working directory

Download video from youtube in Ubuntu terminal

First download and install the program youtube-dl from terminal:

sudo apt-get install youtube-dl

After installation, you can download video from YouTube:

youtube-dl -o file_name.flv youtube-video-link

Sudoers - Community Ubuntu Documentation

Shutting Down From The Console Without A Password

Often people want to be able to shut their computers down without requiring a password to do so. This is particularly useful in media PCs where you want to be able to use the shutdown command in the media centre to shutdown the whole computer.

To do this you need to add some cmnd aliases as follows:

Cmnd_Alias SHUTDOWN_CMDS = /sbin/shutdown, /sbin/halt, /sbin/reboot

You also need to add a user specification (at the end of the file after the "%admin ALL = (ALL) ALL" line so it takes effect - see above for details):

ALL=(ALL) NOPASSWD: SHUTDOWN_CMDS

Obviously you need to replace "" with the username of the user who needs to be able to shutdown the pc without a password. You can use a user alias here as normal.

via Sudoers - Community Ubuntu Documentation.

FilePermissions

FilePermissions - Community Ubuntu Documentation.

Is it possible to quit Google?

BBC News - Is it possible to quit Google?.

How to convert flv to mp3 in Ubuntu

FFmpeg from the repository is not compiled to support restricted formats such as mp3. You can use a third-party repository such as Medibuntu, compile ffmpeg yourself, or use another library, such as: libavcodec-extra-53.

The basic command:

Code:

ffmpeg -i inpuvvideofile.flv outputaudiofile.mp3

By default this will create a 64 kb/s file. You can declare the audio bitrate with -ab:

Code:

ffmpeg -i inpuvvideofile.flv -ab 128k outputaudiofile.mp3

If the flv already has mp3 audio, then there is no need to re-encode. You can just copy the audio stream. This will preserve the audio quality and will be much quicker since there is no re-encoding:

Code:

ffmpeg -i inpuvvideofile.flv -acodec copy outputaudiofile.mp3

Don't know what the audio is? Just ask ffmpeg:

Code:

ffmpeg -i inputvideo.flv

Along with some other information, ffmpeg will provide file details with the above command:

Code:

Stream #0.0: Video: flv, yuv420p, 320x240, 29.97 tb(r)
Stream #0.1: Audio: mp3, 22050 Hz, mono, s16, 56 kb/s

Source:ubuntuforums

64 bit ও 32 bit লিনাক্সে Avro keyboard ইন্সটল করার পদ্ধতি | Ubuntu Library

64 bit ও 32 bit লিনাক্সে Avro keyboard ইন্সটল করার পদ্ধতি | Ubuntu Library.

download-scim-avro.tar.gz 

built instruction from avro

grub2 - Grub Error in Ubuntu 12.04 after upgrade from 11.10

Boot into the Ubuntu Live Cd and open terminal.



1. Identify Ubuntu partition:

sudo fdisk -l

2. Mount it ( replace sda1 with the Ubuntu partition number):

sudo mount /dev/sda1 /mnt

3.Reinstall grub:

sudo grub-install --root-directory=/mnt /dev/sda
sudo update-grub

Solution from: grub2 - Ubuntu 11.10 not showing up in GRUB bootloader after update and restart :( - Ask Ubuntu.

What are Unity's keyboard and mouse shortcuts? - Ubuntu 12.04

What are Unity's keyboard and mouse shortcuts? - Ask Ubuntu.

Show All Running Processes in Linux

Show All Running Processes in Linux.

Subversion Commands

Subversion Complete Reference.

Installing Oracle-JDK in Ubuntu

Download JDK from ORacle. Run Terminal:

chmod u+x jdk-6u31-linux-i586.bin
./jdk-6u31-linux-i586.bin
sudo mv jdk1.6.0_31 /usr/lib/jvm/

#Next line will add java to symlink

sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.6.0_31/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.6.0_31/bin/javac" 1

Or, better if you can set environment variable by adding the following lines at the bottom of .bashrc by "gedit ~/.bashrc":

export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_03
export PATH=$PATH:$JAVA_HOME/bin

You can now check if the java is installed properly in terminal:

java -version
javac -version

These will return the version of java and javac.

Ubuntu Command Collection

• install debian file:

sudo dpkg -i package_name.deb

• install dependency:

sudo apt-get -f install

• install software:

sudo apt-get -f install package_name

• install bundle file:

sudo sh file_name.bundle

• install bin/sh file:

chmod +x file_name.bin
./file_name.bin

• Installing WIRESHARK's dumpcap without allowing non-root users to capture packets:

setcap 'CAP_NET_RAW+eip CAP_NET_ADMIN+eip' /usr/bin/dumpcap

• Find the MAC address:

ifconfig

References:

1. WIRESHARK:

Generics are not supported in -source 1.3 error in Maven Project

When compiling via maven project, you may have encountered following error:

generics are not supported in -source 1.3 error in Maven Project. use -source 5 or higher to enable generics.

Annotation is not allowed in -source 1.3 use -source 5 or higher to enable annotation.

To solve this you must add the below lines at your pom.xml :

    
        
            org.apache.maven.plugins
            maven-compiler-plugin
            
                1.5</source>
                1.5
            
         
    

বসন্তের শুভেচ্ছা

C++ : keywords

32 keywords defined by standard C.

auto	double	int	struct
break	else	long	switch
case	enum	register	typedef
char	extern	return	union
const	float	short	unsigned
continue	for	signed	void
default	goto	sizeof	volatile
do	if	static	while

A list of some commonly used extended keywords:

asm	_cs	_ds	_es
_ss	cdecl	far	huge
interrupt	near	pascal

All C (and C++) keywords are lowercase. Also, uppercase and lowercase are
different: else is a keyword; ELSE is not.