How to quickly scan through whole folder and subfolders to find a keyword in all documents?

grep -iRH "keyword"

How to enable mandarin or Chinese characters or GBK supported in Ubuntu Sublime?

p/s: copied from https://github.com/seanliang/Codecs33/tree/linux-x64

Description (中文说明见README.zh_CN.md)

Due to the limitation of embedded Python with Sublime Text 3, ConvertToUTF8 might not work properly. You can install this plugin to solve the problem.



Installation
Using Package Control to find, install and upgrade Codecs33 is the recommended method to install this plug-in.
Otherwise, you can download this repository as a zip file from one of the branchs (osx, linux-x64, linux-x32) which matchs your platform. Unzip the archive and rename the new folder to Codecs33, then move this folder to Packages folder of Sublime Text (You can find the Packages folder by clicking "Preferences > Browse Packages" menu entry in Sublime Text).

Zip or Unzip or 7z software in Ubuntu? Use PeaZip

https://www.peazip.org/peazip-portable.html

Linux General Commands

https://mp.weixin.qq.com/s/hnhyp8skmLOyorfSsznYaA

How to use 7z to zip and unzip with a password?

From http://www.dotnetperls.com:

7z a secure.7z * -pSECRET

Where:

7z        : name and path of 7-Zip executable
a         : add to archive
secure.7z : name of destination archive
*         : add all files from current directory to destination archive
-pSECRET  : specify the password "SECRET"

To open :

7z x secure.7z

Then provide the SECRET password
Note: If the password contains spaces or special characters, then enclose it with single quotes

7z a secure.7z * -p"pa$$word @|"

How to use github for source code maintainance?

For own repository maintainance, you can do the following steps:-
1. git clone the github_code_as_root
2. cd root
3. run or modify something in the code
4. cd root
5. git add .
6. git commit "changes have been done"
7. git push
(all code in the master branch of github will be updated)


For collaborated project with others, everything is the same, except:
1.git clone the github_code_as_root
2.cd root
3. git checkout -b ninja_branch
4. git status
5. (modify something, blak blak blak)
6. git add .
7. git commit -m "fix more errors in using scores versus score"
8. git push -u origin ninja_branch
(go to github website and pull a request for merging, add someone to review)

How to remove and create folder at the same time in python?

import os
opath = 'output/images'
if os.path.exists(opath):
    shutil.rmtree(opath)  # delete output folder
os.makedirs(opath)  # make new output folder

How to fix docker: Got permission denied while trying to connect to the Docker daemon socket

Method1:

• Create the docker group.

sudo groupadd docker

• Add your user to the docker group.

sudo usermod -aG docker ${USER}

• clean the docker cache
  

rm -rf ~/.docker

• update docker directory right
  

sudo chmod 666 /var/run/docker.sock


 

Method2:

You need to do the following:
To create the docker group and add your user:

• Create the docker group.

sudo groupadd docker

• Add your user to the docker group.

sudo usermod -aG docker ${USER}

• You would need to override the docker permission

sudo chmod -R ugo+rw /var/run/docker.sock

sudo systemctl restart docker

sudo reboot / source ~/.bashrc

• Verify that you can run docker commands without sudo.

docker run hello-world

How to remove a known ip in ssh?

ssh-keygen -f "/home/user/.ssh/known_hosts" -R 192.168.20.123

How to run multi-threading for reading image from camera?

#!/usr/bin/env python

from threading import Thread, Lock
import cv2

class WebcamVideoStream :
    def __init__(self, src = 0, width = 640, height = 480, fps = 30) :
        self.stream = cv2.VideoCapture(src)
        self.stream.set(cv2.CAP_PROP_FRAME_WIDTH, width)
        self.stream.set(cv2.CAP_PROP_FRAME_HEIGHT, height)
        self.stream.set(cv2.CAP_PROP_FPS, fps)
        (self.grabbed, self.frame) = self.stream.read()
        self.started = False
        self.read_lock = Lock()

    def start(self) :
        if self.started :
            print("already started!!")
            return None
        self.started = True
        self.thread = Thread(target=self.update, args=())
        self.thread.start()
        return self

    def update(self) :
        while self.started :
            (grabbed, frame) = self.stream.read()
            self.read_lock.acquire()
            self.grabbed, self.frame = grabbed, frame
            self.read_lock.release()

    def read(self) :
        self.read_lock.acquire()
        frame = self.frame.copy()
        self.read_lock.release()
        return frame

    def stop(self) :
        self.started = False
        self.thread.join()

    def __exit__(self, exc_type, exc_value, traceback) :
        self.stream.release()

if __name__ == "__main__" :
    vs = WebcamVideoStream().start()
    while True :
        frame = vs.read()
        cv2.imshow('webcam', frame)
        if cv2.waitKey(1) == 27 :
            break

    vs.stop()
    cv2.destroyAllWindows()

Cutting the videos based on start and end time using ffmpeg

# -ss start point, -to end point
ffmpeg -i input.mp4 -ss 00:01:00 -to 00:02:00 -c copy output.mp4

# -t trim how many seconds from ss
ffmpeg -i input.mp4 -ss 00:01:00 -t 5 -c copy output.mp4 

This command trims your video in seconds!
I have explained it on my blog here:

-i: This specifies the input file. In that case, it is (input.mp4). -ss: Used with -i, this seeks in the input file (input.mp4) to position. 00:01:00: This is the time your trimmed video will start with. -to: This specifies duration from start (00:01:40) to end (00:02:12).
00:02:00: This is the time your trimmed video will end with. -c copy: This is an option to trim via stream copy. (NB: Very fast)

The timing format is: hh:mm:ss

p/s: https://stackoverflow.com/questions/18444194/cutting-the-videos-based-on-start-and-end-time-using-ffmpeg

How to Use Mandarin / Pinyin / Chinese in Ubuntu？

1. Go to System Settings–> Language Support–> Install/Remove Languages, select Chinese(Simplified)
2. Open the terminal and install the IBus framework with following command:
   

   sudo apt-get install ibus ibus-clutter ibus-gtk ibus-gtk3 ibus-qt4

3. Start the IBus framework. In terminal input:
   

   im-config -s ibus

4. Install the Pinyin engine
   

   sudo apt-get install ibus-pinyin

5. Restart IBus daemon
   

   ibus restart

6. Setting the IBus
   

   ibus-setup

   In the popup window, switch to Input Method tab，click the Add button to choose the Chinese input method installed just now.
7. Go to the Text Entry (from the right-top corner of the window or from the System Settings -> Text Entry) for the shortcut of input method exchange.
8. Select Intelligent Pinyin

p/s: copied from https://leijinmin.wordpress.com/2017/06/16/install-google-pinyin-into-ubuntu-16-04/ 

How to delete multiple lines in vim?

1. Press Esc.

2. Move the cursor to the first line you want to remove.

3. Use one of the following commands (replacing [#] with the number of lines):

[#]dd

How to get the file base name from a path using python?

>>> import os
>>> base=os.path.basename('/root/dir/sub/file.ext')
>>> base
'file.ext'