CRLF vs LF

These days I am coding a Linux shell running for AZcopy, since my laptop is running windows, so I switch between two operations systems. The strange problem came soon:

  1. ./azCopyToAzure.sh: line 7: $’\r’: command not found
  2. source ./config.cfg can not found
  3. when I was using echo ${log_dir}!!!, the result is !!!XXX, basically, the !!! will come to the beginning and overwrite ${log_dir}

After wasting almost two days, I found the problem. It caused by difference between end of sequence in windows and Linux. Here is from wiki:

The term CRLF refers to Carriage Return (ASCII 13, \r) Line Feed (ASCII 10, \n). They’re used to note the termination of a line, however, dealt with differently in today’s popular Operating Systems. For example: in Windows both a CR and LF are required to note the end of a line, whereas in Linux/UNIX a LF is only required. In the HTTP protocol, the CR-LF sequence is always used to terminate a line.

https://www.owasp.org/index.php/CRLF_Injection

In vs code , we have to change this setting at the bottom of right side.

I thought there should not be many person developing bash on windows, but if you are, hope this can solve some of your problems.

Raspberry PI Security

Lots of ready-to-use opensource project can be found on internet for raspberry PI object detection. Most of them can do very well to motion detection or object classification. I am thinking how to merge them together to make a practical security system that can help all of us to make our home safety. Since It is open source, I will share my design, source code and project milestone. ( mostly to push myself to finish it eventually 🙂

Design:

  1. start camera to capture each frame
  2. save the first frame as reference. and this reference frame will be replaced every 5 mins when there is no movement detected.
  3. continuously compare the current frame with the reference frame.
  4. if any movement detected, draw some interesting areas.
  5. loop these interesting areas, if its size out of threshold, move it to next DNN network.
  6. use DNN network to classify the object.
  7. if object is human, trigger dedicated process “Event process”. includes, recording video, send notification and make speaker noise.
  8. loop to the next frame.

Milestone:

Oct 10th-15th: finish basic function to detect movement, recording video and send mail.

Oct 16th-22th: add DNN network

Oct 22th-30th: add speaker and integration test.

Potential update:

  • GPU accelerate on Cuda device
  • GUI
  • restful API

Source:

https://github.com/neoaksa/raspiberry-security

Demo(till Oct 15th):

Reference:

Deep learning: How OpenCV’s blobFromImage works. https://www.pyimagesearch.com/2017/11/06/deep-learning-opencvs-blobfromimage-works/

Raspberry Pi: Deep learning object detection with OpenCV. https://www.pyimagesearch.com/2017/10/16/raspberry-pi-deep-learning-object-detection-with-opencv/

how to install opencv on the raspberry pi 3 Model b+ (with camera) https://pysource.com/2018/10/31/raspberry-pi-3-and-opencv-3-installation-tutorial/

Home surveillance and motion detection with the Raspberry Pi, Python, OpenCV, and Dropbox. https://www.pyimagesearch.com/2015/06/01/home-surveillance-and-motion-detection-with-the-raspberry-pi-python-and-opencv/

Windows + Linux = WSL

I still remembered the song “pineapple”, the singer is a wired middle age man, looks like this: Today, what I wanna talk about is similar to “pineapple”. It’s called “WSL”.

what is WSL?

WSL is an abbr for windows subsystem for linux, where you can run linux on windows like an app.

How does it work?

very simple!

  1. run windows store , find ubuntu and install it.
  2. check the wsl option in turn windows feature on or off
    • you need to restart you computer after check it.
  3. run ubuntu as your application, all commands are same.

Where is GUI?

Sorry, by default, it is only a kernal system. So, basicly you have to run with commands. But there is a workaround: Xming. You can find detail here . I only tried two steps: install ‘Xming’ and setting display export DISPLAY=:0 . Then I did successfully run Geany with GUI! Don’t tell me you don’t know how to run app on consoler.

Existing Problem

I tried install program by sanpd, but it awalys showed me error message.

Who can try it

If you like both Linux and windows, WSL gives you a opportunity to waive the dual booting problem. You can aslo access windows drivers under /mnt/.

Have fun!

Hello world!

Well. I have to agree “Hello world” is one of my favor titles. Since I bought a raspberry pi which supposed to do some deep learning works, like object detection, I have to do something before my camera coming from amazon.

So, I guess creating a pro personal website would be a good choice. I refer “Build a LAMP Web Server with WordPress”  and “offcial website“. In an nutshell, not hard stuffs, but some points need to be care.

Installation:

    1.  if you change password through mySQL directly, you have to transfer pwd through MD5 tool, here is one.
    2. if you happen to unable to upload file, please install “sudo apt-get install php7.0-gd” and restart apache “sudo service apache2 restart“.
    3. I initially started with offical website guide, but I suddenly realized I need to install LAMP(Linux, ApacheMySQLPHP)
    4. There might be requests for setting FTP when installing plugins, this can be solved by edit wp-config.php with adding “define(‘FS_METHOD’, ‘direct’);
    5. Give www-data authority to access wordpress folder: “sudo chown -R www-data:www-data /var/www/html“, /var/www/html is my wordpress folder

Backup:

  1. UpdraftPlus would be a good choice which provides several romote storage methods inculding google dirve.

After almost 2 hours mess around, I finally  create this website on raspberry!