Try to clone a repo needs auth, when prompt "Are you sure you want to continue connecting (yes/no/[fingerprint])?", enter fingerprint(you can get it from the result of ssh-keygen). Then you will get "Please type 'yes', 'no' or the fingerprint: " prompt, enter "yes".

I tried the following commands and was able to turn on the Bluetooth:

sudo apt update && sudo apt upgrade
sudo systemctl start bluetooth
rfkill unblock bluetooth

ps: reboot after execute commands

After that, I was able to turn on Bluetooth on Ubuntu, but I had an error when I connect a pair of Jabra earphones.

Then tried the following way:

1. Remove the Jabra device from Ubuntu.
2. Turn off other Bluetooth connections of the Jabra earphones.
3. Press both the left and the right buttons of the earphones to switch to connection mode.
4. Connect from Ubuntu again.

Finally, connect my Bluetooth earphones to Ubuntu!

Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed: SocketException: Error connecting to 127.0.0.1:27017 :: caused by :: No connection could be made because the target machine actively refused it. : connect@src/mongo/shell/mongo.js:372:17 @(connect):2:6 exception: connect failed exiting with code 1

Share an easy way to fix that:

• Press Ctrl + Shift + Esc, open Task manager

• Open the Services tab, locate MongoDB

• Right-click and select Start

For a career changer and coding boot camp graduate, lack of study and professional experiences will be the most challenge we will face. That will leads to no response or rejection before the first interview.

Since we chose boot camp as the way we change our careers, we saved time and money for learning at University or College, we will spend more time on job searching. Personal projects and volunteer experiences will help us shorten this process.

2. There are too many tech skills to learn

As in the tech area, things change every day, and you have too many techs to choose from. JavaScript, Java, Python, SQL, no-SQL, AWS, Asure..... I have spent too much time expanding my tech stack. I hope I have chosen one and stick to it. My suggestion is to stick to JavaScript and try to master it. You will use it to solve all tests you will face in interviews, and after you get a job, you will know what other techs you need to learn.

3. Keep applying

Apply for 10 positions a day. 100 applications will lead you to 10 interviews, and 10 interviews will lead you to 1 offer. This suggestion is from a friend, it fits my situation.

4. Expand your network

Networks will help you get a job, even if you didn't do well in all the above aspects.

I use https://freehostia.com, for more free options, visit https://smartblogger.com/free-wordpress-hosting

#2. Set up your domain's NS.

Find name servers address from your host, set NS address.

#3. Install WordPress on your host.

#4. Sign in to your wp-admin page.

WordPress Admin URL: http://yourdomain.com/wordpress/wp-login.php

#5. Choose a free theme or install your downloaded theme

Navigate to Appearance > Themes > Add New -> Upload theme Choose theme.zip file. Wait while the theme is uploading, install and activate it.

#6. Set up and customize theme

#7. Publish website

string.length

returns the length of a string

.slice()

string.slice(start, end)

returns the extracted part in a new string, end not included

If a parameter is negative, the position is counted from the end of the string.

If you omit the second parameter, the method will slice out the rest of the string.

.substring()

string.substring(start, end)

substring() is similar to slice().

The difference is that substring() cannot accept negative indexes.

.substr()

string.substr(start, length)

substr() is similar to slice().

The difference is that the second parameter specifies the length of the extracted part.

If you omit the second parameter, substr() will slice out the rest of the string.

If the first parameter is negative, the position counts from the end of the string.

.replace()

string.replace("old", "new")

The replace() method replaces a specified value with another value in a string.

The replace() method does not change the string it is called on.

The replace() method returns a new string.

The replace() method replaces only the first match

If you want to replace all matches, use a regular expression with the /g flag set.

To replace case insensitive, use a regular expression with an /i flag (insensitive).

excerpt from：https://www.w3schools.com/js/js_string_methods.asp

Type Selector

Selects an element by its type.

h1

Class Selector

Selects an element by the class attribute value, which may be reused multiple times per page.

.blue-button

ID Selector

Selects an element by the ID attribute value, which is unique and to only be used once per page.

#submit

Child Selectors

Descendant Selector

Selects an element that resides anywhere within an identified ancestor element.

div h2

Direct Child Selector

Selects an element that resides immediately inside an identified parent element.

div > p

Sibling Selectors

General Sibling Selector

Selects an element that follows anywhere after the prior element, in which both elements share the same parent

h3 ~ p

Adjacent Sibling Selector

Selects an element that follows directly after the prior element, in which both elements share the same parent.

h3 + p

Attribute Selectors

Attribute Present Selector

Selects an element if the given attribute is present

a[target]

Attribute Equals Selector

Selects an element if the given attribute value exactly matches the value stated

a[href="http://google.com/"]

Attribute Contains Selector

Selects an element if the given attribute value contains at least once instance of the value stated

a[href*="login"]

Attribute Begins With Selector

Selects an element if the given attribute value begins with the value stated

a[href^="https://"]

Attribute Ends With Selector

Selects an element if the given attribute value ends with the value stated

a[href$=".pdf"]

Attribute Spaced Selector

Selects an element if the given attribute value is whitespace-separated with one word being exactly as stated

a[rel~="tag"]

Attribute Hyphenated Selector

Selects an element if the given attribute value is hyphen-separated and begins with the word stated

a[lang|="en"]

Pseudo-classes

Link Pseudo-classes

Selects a link that has not been visited by a user

a:link

Selects a link that has been visited by a user

a:visited

User Action Pseudo-classes

Selects an element when a user has hovered their cursor over it

a:hover

Selects an element when a user has engaged it

a:active

Selects an element when a user has made it their focus point

a:focus

User Interface State Pseudo-classes

Selects an element in the default enabled state

input:enabled

Selects an element in the disabled state, by way of the disabled attribute

input:disabled

Selects a checkbox or radio button that has been checked

input:checked

Selects a checkbox or radio button that neither been checked or unchecked, leaving it in an indeterminate state

input:indeterminate

Structural & Position Pseudo-classes

Selects an element that is the first within a parent

li:first-child

Selects an element that is the last within a parent

li:last-child

Selects an element that is the only element within a parent

div:only-child

Selects an element that is the first of its type within a parent

p:first-of-type

Selects an element that is the last of its type within a parent

p:last-of-type

Selects an element that is the only of its type within a parent

img:only-of-type

Selects an element that matches the given number or expression, counting all elements from the beginning of the document tree

li:nth-child(2n+3)

Selects an element that matches the given number or expression, counting all elements from the end of the document tree

li:nth-last-child(3n+2)

Selects an element that matches the given number or expression, counting only elements of its type from the beginning of the document tree

p:nth-of-type(3n)

Selects an element that matches the given number or expression, counting only elements of its type from the end of the document tree

p:nth-last-of-type(2n+1)

Target Pseudo-class

Selects an element whose ID attribute value matches that of the URI fragment identifier

section:target

Empty Pseudo-class

Selects an element that does not contain any children or text nodes

div:empty

Negation Pseudo-class

Selects an element not represented by the stated argument

div:not(.awesome)

Pseudo-elements

Textual Pseudo-elements

Selects the first letter of text within an element

.alpha:first-letter

Selects the first line of text within an element

.bravo:first-line

Generated Content Pseudo-elements

Creates a pseudo-element inside the selected element at the beginning

div:before

Creates a pseudo-element inside the selected element at the end

a:after

Fragment Pseudo-element

Selects the part of a document which has been selected, or highlighted, by a users’ actions

::selection

Excerpted from：https://learn.shayhowe.com/advanced-html-css/complex-selectors/

When first start Windows computer, may face an error when using docker commands

error during connect: This error may indicate that the docker daemon is not running.: Get "http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.24/images/json": open //./pipe/docker_engine: The system cannot find the file specified.

Execute the following command in PowerShell to switch Docker daemon:

& 'C:\Program Files\Docker\Docker\DockerCli.exe' -SwitchDaemon

2. Image Commands

2.1 Displays the available commands:

docker image --help

2.2 Lists all the images:

docker image ls

2.3 Pulls an image from dockerhub:

docker image pull

docker image pull alpine

docker image pull alpine: 3.15

2.4 Build an existing image:

docker image build

2.5 Removes all unused images

docker image prune

2.6 Tags an image

docker image tag

2.7 Removes an image

docker image rm

3. Container Commands

3.1 See available commands

docker pull --help

3.2 Pulls a container

docker pull

3.3 Lists containers

docker container ls

3.4 Runs a container

docker run

3.5 Lists all containers

docker ps

3.6 Stop a container

docker stop

3.7 Start a container

docker start

3.8 Interact with a container

docker exec

3.9 Remove a stopped container

docker container rm

3.10 Removes all stopped containers

docker container prune

4. Dockerfile

4.1 Image and version

FROM

4.2 Adds file in build to the image

ADD

4.3 Same as ADD but limited to the project directory

COPY

4.4 Environment variables

ENV

4.5 Ports to expose

EXPOSE

4.6 Switch to a specific user

USER

4.7 Set the working directory

WORKDIR

4.8 Command that needs to be run on execution

CMD

4.9 Practice

Dockerfile:

FROM node:alpine

COPY . /app

WORKDIR /app

CMD ["node", "app.js"]

In PowerShell:

docker build -t docker-node .

docker run --rm docker-node

1. Can I learn to code by just listening carefully in class?

No, it's not enough! Most students cannot understand everything the teacher teaches in class. You have to listen carefully and follow the teacher, but you need more practice to make the knowledge your own.

2. How should I study in a coding bootcamp?

Pre-read the material before class, summarize what you don't understand, listen carefully in class, and look for answers.

Ask questions you don't understand.

Practice more after class. If the exercises provided in the course are not enough, you can ask your teacher and TA to recommend more exercises or tutorials.

3. How many hours a day should I spend studying and practicing coding?

As much as you can.

4. What will I get at the end of this course?

You will get basic javascript full-stack web development knowledge, a project to showcase your skills, and most importantly, you will have the skills to continue learning and self-learning.

docker --version

2. Run Container

docker run -it alpine

3. Check who am I

whoami

root

4. Check where am I

pwd

\

5. List and Navigate

ls

cd

cd .. && ls

6. Files and Directories

mkdir touch mv echo cat rm more less head tail

7. Exiting and Cleanup

Containers

docker ps

docker container ls -a

docker container prune

Images

docker image ls -a

docker image prune

8. Install vim in Alpine

apk update

apk add vim

9. Save and exit in vim

:w save

:q exit

:q! exit and throw unsaved change.

I will introduce the easier way - SSH, in this post.

Steps:

1. Open a terminal in VS Code.
2. Enter ssh-keygen in the terminal, and press the enter key.
3. There will be prompted for a “passphrase” (i.e., password). If you decide to not set a password, just press the enter key. Otherwise, input a password (no need to be the same as your Github password), then press the enter key, then input the password again, then press the enter key.
4. Enter cat ~/.ssh/id_rsa.pub in the terminal, and press the enter key. Your "public key" will be shown in the terminal. Copy the public key, from "ssh-rsa" to the end.
5. Go to https://github.com/settings/keys and log in to your Github account if you haven't done that yet.
6. Click New SSH key . Paste your copied public key into the text box under Key. You can also optionally input a title under Title, like "my laptop". Then click Add SSH key.

Now you are all set to log into Github from your VS Code. If you input a password in step 3, you might be asked to enter that.

After the connection is configured, you can connect to your private RDS DB instance using an SSH tunnel.

(Excerpted from AWS Q&A)

2. Connect to the instance.

3. Install MySQL

sudo su

yum install wget -y

wget https://dev.mysql.com/get/mysql80-community-release-el8-1.noarch.rpm

md5sum mysql80-community-release-el8-1.noarch.rpm

rpm -ivh rpm -ivh mysql80-community-release-el8-1.noarch.rpm

yum module disable mysql 
y

yum install mysql-community-server

systemctl start mysqld

systemctl status mysqld

ps -ef | grep mysql

cat /var/log/mysqld.log|grep temp

mysql -u root -p mysql

mysqladmin -u root -p password

mysql -u root -p mysql

select * from mysql.time_zone;

mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root -p mysql