Tutorial Learn Linux The Hard Way (β version) - Exercise 3. Bash: The shell, .profile, .bashrc, .bash_history

When working with Linux using CLI (command line interface), you are interacting with a program called a shell. All you type is passed to the shell, which interprets what you have typed, does parameters expansion (which is somewhat similar to brace expansion in algebra) and executes programs for you. Shell which we will be using is calledBash, which stands for Bourne Again Shell, which is in turn a pun. Now I will show you general overview of how the bash works in plain English:

Tutorial Learn Linux The Hard Way (β version) - Exercise 2. Text Viewer, The: less is More

Now you can edit text files, that is nice. But what if you want just to view a text file? Of course, you could use vim for that, but very often it is overkill. And two more thing to consider:

• If you want to view really large file, you will want to view it in a program which is as fast as possible.
• Often you would not want to accidentally change something in a file.

Tutorial Learn Linux The Hard Way (β version) - Exercise 1: Text Editor, The: vim

In Linux, as in any Unix-like OS, everything is just a file. And Unix philosophy states that configuration files must be human readable and editable. In almost all cases, they are just plain text. So, first things first, you must learn how to edit a text file.

For this I strongly advise you to learn basics of vim, which is one of most powerful tools to work with texts in Linux. Vim is reimplementation of vi, the editor written in 1976 by Bill Joy. Vi implemented a concept so successful that even Microsoft Visual Studio 2012 has a plugin, which provides a mode compatible with this more than 35 year old editor. You may play with right here (this is real Linux running in your browser). After you are done go and get get my virtual appliance at last.

Tutorial Learn Linux The Hard Way (β version) - Exercise 0

Exercise 0. The Setup

Windows, Manual Installation

Windows, VirtualBox virtual appliance (preconfigured image in .ova format)

What you will need

1. VitualBox, a virtual machine player.
2. putty, terminal emulator.
3. Preconfigured VirtualBox image with Debian.
   

Tutorial Learn Linux The Hard Way (β version) - Introduction

Introduction

This is a simple guide written in “Learn X the hard way” style, author of which is Zed A. Shaw. The purpose of it is to give you some experience in working with Unix-like system. There are many good UNIX-Like systems out there, for example FreeBSD, OpenBSD, OpenSolaris and even MAC OS X, just to name a few. When deciding which system to use in this guide I chose Linux mainly because it is most popular UNIX-like server operating system, which means what you have much bigger chance encountering it in the wild in comparsion to other UNIX derivatives. And Linux-related skills are relatively easy transferable to other UNIX-likes.

Hướng dẫn toàn tập cho người mới bắt đầu học điện tử - phần 4

Nguồn : http://techmaster.vn/

Dãy điện trở song song

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Totorial - How to setup PI WEB SERVER

Overview :

• Download the latest Rasbian
• Prepare a SD / Micro SD card to receive the downloaded Images.
• Un compress and Transfer the downloaded Raspbian Image to the SD / Micro SD card.
• Install Raspbian.
• Configure Raspbian for a static network.
• Install  Apache Web Server
• Install PHP and Associated Packages
• Install MySql
• Configure your router to access your Webserver and a domain name that points to your webserver.

Hướng dẫn toàn tập cho người mới bắt đầu học điện tử - phần 3

Nguồn : http://techmaster.vn/

Giá trị điện trở chuẩn hoặc thông thường

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Hướng dẫn toàn tập cho người mới bắt đầu học điện tử - phần 2

Nguồn : http://techmaster.vn/

Giới thiệu về: Điện trở

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Bonus 2 : Tip and trick with Raspberry Pi

GETTING THE NETWORK DETAILS

To scan for WiFi networks, use the command

sudo iwlist wlan0 scan | grep 'ESSID\|IE: IEEE'

This will list all available WiFi network names and their encryption methods. Look for yours in the list:

1. ESSID:"yournetwork". This is the name of the WiFi network, find the one that you want to use.
2. IE: IEEE 802.11i/WPA2 Version 1.
   1. This is the authentication used; in this case it is WPA2, the newer and more secure wireless standard which replaces WPA1. This guide should work for WPA or WPA2, but may not work for WPA2 enterprise; for WEP hex keys.

ADDING THE NETWORK TO THE RASPBERRY PI

Open the wpa-supplicant configuration file in nano:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

Go to the bottom of the file and add the following:

network={
    ssid="The_ESSID_from_earlier"
    psk="Your_wifi_password"
}

In the case of the example network, we would enter:

network={
    ssid="testing"
    psk="testingPassword"
}

Now save the file by pressing ctrl+x then y, then finally press enter.

At this point, wpa-supplicant will normally notice a change has occurred within a few seconds, and it will try and connect to the network. If it does not, either manually restart the interface with

sudo ifdown wlan0

and

sudo ifup wlan0

or reboot your Raspberry Pi with

sudo reboot

You can verify if it has successfully connected using ifconfig wlan0. If the inet addr field has an address beside it, the Pi has connected to the network. If not, check your password and ESSID are correct.

You can also check your DHCP server to see if it gave out a new IP address.

Remove any unneeded packages

There will eventually be packages that are unneeded. Apt-get can get rid of them by issuing this command:

sudo apt-get autoremove

Remote Desktop

Installing this allows you to connect via RDP on Windows.

sudo apt-get install xrdp

Add Chrome/Chromium to Desktop

Adds “Chrome” web browser to the GUI interface.

sudo apt-get install chromium-browser

Check CPU Clock Speed

This will show the current CPU clock speed in hertz

 cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

Raspi-config

This is the initial configuration utility. I always forget its name..

sudo raspi-config

Hướng dẫn toàn tập cho người mới bắt đầu học điện tử - phần 1

Nguồn : http://techmaster.vn/

Mọi khởi đầu trong bất cứ lĩnh vực nào cũng có rất nhiều khó khăn, nhưng nếu bạn có động lực và quyết tâm mạnh mẽ thì chắc chắn bạn sẽ thành công. Hầu hết các sinh viên kỹ thuật điện tử đều muốn tự tay làm ra một sản phẩm gì đó. Trải nghiệm thực tế khi làm một sản phẩm nào đó là một cách học tuyệt vời. Mặc dù nó là rất quan trọng nhưng hầu hết các sinh viên không được hướng dẫn đúng đắn và họ không biết nên bắt đầu từ đâu. Tôi tin rằng loạt bài hướng dẫn này sẽ giúp cho những ai yêu thích điện tử có thể dễ dàng bắt tay vào làm các dự án của họ.

CÀI ĐẶT RASPBERRY PI - Bài 9 : SETUP DROPBOX FOR MOTION ON THE RASPBERRY PI

Raspbian, the recommended default operating system of the Raspberry Pi, does not come with a native Dropbox package. The hacks I saw online were all pretty sloppy, with many showing how to bounce files from your raspberry pi to another device like a desktop PC that has dropbox installed, then using that PC to sync files. I wanted Dropbox synchronization for only a single folder, and for one purpose: to collect the photos my webcam takes when using the motion software.

I decided to use Dropbox’s Python API to create a script that could save my security footage. I had a number of uninvited painters scheduled to come to my apartment while I was away at work and needed something that would save to a remote location. The code that follows is tailored to the motion program. Since motion can automatically execute a program or script upon writing a file (ie: saving a photo or video triggered by motion), I decided to take advantage of this and upload each file individually as opposed to running an additional script that continually monitors the filesystem for changes.

CÀI ĐẶT RASPBERRY PI - Bài 8 : SETUP Raspberry Pi as low-cost HD surveillance camera

Build a low-cost HD video surveillance cam with worldwide access from any browser

Introduction

This article describes how to build a surveillance cam based on a Raspberry Pi micro-computer which records HD video when something moves in the monitored area. Live picture can be viewed from any web browser, even from your mobile while you're on the road.

What you will get:

• See live stream in any web browser from anywhere
• Record any motion into video file

Hardware components

      We need some hardware for this project. This is a list of the major things we need:

• Raspberry Pi 2 Model B: (Link : http://hshop.vn/products/moy-tonh-raspberry-pi-2-model-b-1gb-made-in-prc)
• Raspberry Pi Camera Module (Link : http://hshop.vn/products/camera-hong-ngoai-raspberry-pi-noir)

CÀI ĐẶT RASPBERRY PI - Bài 7 : Điều khiển Raspberry Pi sử dụng SSH (Windows, Linux)

Mục đích:

• Cấu hình Raspberry Pi để sử dụng tính năng điều khiển từ xa qua SSH
• Cấu hính trên Windows, Linux để điều khiển SSH

Chuẩn bị:

• Raspberry Pi có hệ điều hành (Raspbian Wheezy hoặc Jessie)
• Máy tính chạy: Windows, Linux hoặc Mac

Tiến hành:

Bước 1. Cấu hình Raspberry Pi

Để có thể điều khiển Raspberry Pi sử dụng SSH thì Raspberry Pi phải được Enable SSH server.

Thông thường thì SSH Server được mở mặc định.