Month: September 2021

TODO: Using foobar2000 to verify music file integrity

Using foobar2000 to verify music file integrity

Couldn't found install component feature in MacOS version.

Download File Integrity Verifier

Download component from following location

File Integrity Verifier

Install component

Install component using following steps

  • Open the foobar2000 preferences dialog (click "File | Preferences" or use the CTRL+P keyboard shortcut).
  • Select the Components page.
  • Either click the Install... button and locate the component archive, or simply drag it on to the list.
  • Click OK ...
  • Restart.

Testing

Tested on following formats

  • flac

Cons

  • Failed to test on dff format.

TODO

Test

Replace audio in a video file

Replace audio in a video file

When downloaded video file, there could be a reason requires replace audio due to different language, etc.

Extract audio from a video file

For example, extract audio from with_audio.mp4 and save audio as file output-audio.acc

ffmpeg -i with_audio.mp4 -map 0:a:0 -c copy output-audio.aac
ffmpeg -i with_audio.mp4 -vn -acodec copy output-audio.aac

Merge video and audio into one file

Following command give two inputs, first one is video file (index 0), second one is audio file (index 1). The first -map means getting first input (index 0) as video in first output (out_index 0), and the second -map means getting second input (index 1) as audio in first output (out_index 0).

ffmpeg -i without_audio.mp4 -i output-audio.aac -c:v copy -map 0:v:0 -map 1:a:0 new.mp4

Install self generated CA certificate into Linux OS

Install self generated CA certificate into Linux OS

To trust self generated CA from client system, following steps can be used.

Retrieve CA certificate from server

Copy from CA certificate using browser

Click on lock icron beside address bar of browser, then view certificates.

Copy from server,

The self generated CA certificate normally can be found in server, such as xxxx.ca.crt.

Run command to retrieve from service

Following command will print out CA certificate, remove unnecessary lines, such as DONE, if any.

Note: I haven't validated the certificate retrieved using this method.

openssl s_client -showcerts -connect [server_address]:[port] < /dev/null | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p'

Install CA certificate

Copy CA certificate into /usr/local/share/ca-certificates directory, such as xxxx.ca.crt, then run update-ca-certificates command to update system CA, then restart impacted service.

cp <xxxx.ca.crt> /usr/local/share/ca-certificates
update-ca-certificates
systemctl restart <service>

Note: the certificate file name must be .crt

Test CA

Run following command, should return 0 (ok) as below.

openssl s_client -connect server_address:443 -CApath /etc/ssl/certs

...
Verify return code: 0 (ok)

Configure trust self generated CA certificate of docker registry

Configure trust self generated CA certificate of docker registry

When self generated CA certificate has not been trusted by docker client, following error occurres

... x509: certificate signed by unknown authority

Install CA certificate for docker only

Docker can install registry CA as /etc/docker/certs.d/<registry[:port]>/ca.crt. For example,

/etc/docker/certs.d/my-registry.example.com:5000/ca.crt

Note: If port is 443, it should be omitted. Otherwise, it won't work.

Install CA certificate into system folder

To install self generated CA certificate for operating system, follow the page below.

Install self generated CA certificate into Linux OS

Restart docker service to take effect

The restart docker service after CA certificate installed.

systemctl restart docker

Increase client_max_body_size in NGINX for docker registry

Increase client_max_body_size in NGINX for docker registry

Error "413 Request Entity Too Large" occurred when push image to docker registry.

To fix this issue, add client_max_body_size in NGINX configuration file for docker registry as below, then restart NGINX.

server {
    listen 443;
    server_name hub.bx.net docker.bx.net registry.bx.net dockerhub.bx.net;

    location /v2/ {
        proxy_pass https://registry.my_bridge/v2/;
        proxy_set_header  Authorization $http_authorization;
        proxy_pass_header Authorization;
    }

    client_max_body_size 100M;
}

Backup docker container using shell script

j# Backup docker container using shell script

Backup

Using following shell script to backup docker container with date tag

#!/bin/bash
# backup-docker.sh <container_name> <registry_path>

container=$1            # <container_name>
repo_prefix=$2          # <registry>/<prefix>
registry=${repo_prefix//\/*/}

repo_name=$repo_prefix/`hostname`/$container
repo_path=$repo_name:`date +%Y%m%d`

docker commit $container $repo_path
docker login $registry
docker push $repo_path

Note: If following certification error occurred, follow the page below to install ceritficate.

Configure trust self generated ca certificate of docker registry

List repo

Using following shell command to list repo list in docker registry

curl https://bianxi:$PASSWORD@${registry}/v2/_catalog

Sample output

{"repositories":["bianxi/dnsmasq","bianxi/heart/dnsmasq"]}

List tags

Using follwing shell command to list tags for one repo in docker registry

echo curl https://bianxi:$PASSWORD@${registry}/v2/${repo}/tags/list

Sample output

{"name":"bianxi/heart/dnsmasq","tags":["20210620","20210621","20210622","20210623","20210624","20210625","20210626","20210627"]}

Get digest for tag

Get digest by pull image

docker pull registry.bx.net/bianxi/heart/dnsmasq:20210624

Sample output

20210624: Pulling from bianxi/heart/dnsmasq
...
22b5d63ad977: Already exists
8e2e66517d7e: Pull complete
Digest: sha256:7535af1f65524f9200b901fc31b9c779819e45c0502ef99605666842a319908f

Verify digest

curl https://bianxi:$PASSWORD@registry.bx.net/v2/bianxi/heart/dnsmasq/manifests/sha256:xxxxxxxxxxxxxxxx
curl -v --silent -H "Accept: application/vnd.docker.distribution.manifest.v2+json" -X GET https://bianxi:$PASSWORD@registry.bx.net/v2/bianxi/heart/dnsmasq/manifests/20210624 2>&1 | grep Docker-Content-Digest | awk '{print ($3)}'

Delete local repo

docker rmi registry.bx.net/bianxi/heart/dnsmasq:<tag>

Delete tag

curl -X DELETE https://bianxi:$PASSWORD@registry.bx.net/v2/bianxi/heart/dnsmasq/manifests/sha256:xxxxxxxxxxxxxxxx

Run garbage-collect

docker exec registry bin/registry garbage-collect --delete-untagged /etc/docker/registry/config.yml

Restart registry if necessary

docker restart registry

Create your website with blocks

Create your website with blocks

This is an example page from WordPress.

Add block patterns

Block patterns are pre-designed groups of blocks. To add one, select the Add Block button [+] in the toolbar at the top of the editor. Switch to the Patterns tab underneath the search bar, and choose a pattern.

Frame your images

Twenty Twenty-One includes stylish borders for your content. With an Image block selected, open the "Styles" panel within the Editor sidebar. Select the "Frame" block style to activate it.

Overlap columns

Twenty Twenty-One also includes an overlap style for column blocks. With a Columns block selected, open the "Styles" panel within the Editor sidebar. Choose the "Overlap" block style to try it out.

“Roses Trémières” by Berthe Morisot
“In the Bois de Boulogne” by Berthe Morisot
“Young Woman in Mauve” by Berthe Morisot

Hide title in blog body when displayed in blog list in WordPress

Hide title in blog body when displayed in blog list in WordPress

In order to have a complete document in each blog, blog title is saved in blog body as well.

Blog appears in blog list with title in blog body.

screen

Blog appears in blog list without title (hidden) in blog body.

screen

To hide the blog title in blog list, which is in <h1> or # form, using following code.

.wpbstarter-blog-list .entry-content h1 {
  display: none;
}

Another way to hide it, this can have more control.

.wpbstarter-blog-list .entry-content h1 {
  font-size: 0;
  width: 1px;
  height: 1px;
  display: inline-block;
  overflow: hidden;
  position: absolute!important;
  border: 0!important;
  padding: 0!important;
  margin: 0!important;
  clip: rect(1px,1px,1px,1px);
}

How to use Markdown for writing technical documentation

Source: How to use Markdown for writing technical documentation

How to use Markdown for writing technical documentation

Adobe technical documentation articles are written in a lightweight markup language called Markdown, which is both easy to read and easy to learn.

As we are storing Adobe Docs content in GitHub, it can use a version of Markdown called GitHub Flavored Markdown (GFM), which provides additional functionality for common formatting needs. Additionally, Adobe extended Markdown in a few ways to support certain help-related features such as notes, tips, and embedded videos.

Markdown basics

Headings

To create a heading, use a hash mark (#) at the beginning of a line:

# This is level 1 (article title)
## This is level 2
### This is level 3
#### This is level 4
##### This is level 5

Basic text

A paragraph requires no special syntax in Markdown.

To format text as bold, you enclose it in two asterisks. To format text as italic, you enclose it in a single asterisk:

   This text is **bold**.
   This text is *italic*.
   This text is both ***bold and italic***.

To ignore Markdown formatting characters, use \ before the character:

This is not \*italicized\* type.

Numbered lists and bullet lists

To create numbered lists, begin a line with 1. or 1), but don't use both formats within the same list. You don't need to specify the numbers. GitHub does that for you.

1. This is step 1.
1. This is the next step.
1. This is yet another step, the third.

Displayed:

  1. This is step 1.
  2. This is the next step.
  3. This is yet another step, the third.

To create bullet lists, begin a line with * or - or +, but don't mix the formats within the same list. (Do not mix bullet formats, such as * and +, within the same document.)

* First item in an unordered list.
* Another item.
* Here we go again.

Displayed:

  • First item in an unordered list.
  • Another item.
  • Here we go again.

You can also embed lists within lists and add content between list items.

1. Set up your table and code blocks.
1. Perform this step.

   ![screen](https://experienceleague.adobe.com/docs/contributor/assets/adobe_standard_logo.png)
1. Make sure that your table looks like this: 

   | Hello | World |
   |---|---|
   | How | are you? |  
1. This is the fourth step.

   >[!NOTE]
   >
   >This is note text.

1. Do another step.

Displayed:

  1. Set up your table and code blocks.

  2. Perform this step.

    screen

  3. Make sure that your table looks like this:

    Hello World
    How are you?
  4. This is the fourth step.

    [!NOTE]

    This is note text.

  5. Do another step.

Tables

Tables are not part of the core Markdown specification, but Adobe supports them to an extent. Markdown doesn't support multiple lines lists in cells. Best practice is to avoid using multiple lines in tables. You can create tables by using the pipe (|) character to delineate columns and rows. Hyphens create each column's header, while pipes separate each column. Include a blank line before your table so it's rendered correctly.

| Header | Another header | Yet another header |
|--- |--- |--- |
| row 1 | column 2 | column 3 |
| row 2 | row 2 column 2 | row 2 column 3 |

Displayed:

Header Another header Yet another header
row 1 column 2 column 3
row 2 row 2 column 2 row 2 column 3

Simple tables work adequately in Markdown. However, tables that include multiple paragraphs or lists within a cell are difficult to work with. For such content, we recommend using a different format, such as headings & text.

For more information on creating tables, see:

Links

The Markdown syntax for an inline link consists of the [link text] portion, which is the text that will be hyperlinked, followed by the (file-name.md) portion, which is the URL or file name that's being linked to:

[link text](file-name.md)

[Adobe](https://www.adobe.com)

Displayed:

Adobe

For links to articles (cross-references) within the repository, use relative links. You can use all relative link operands, such as ./ (current directory), ../ (back one directory), and ../../ (back two directories).

See [Overview example article](../../overview.md)

For more information on linking, see the Links article of this guide for linking syntax.

Images

![Adobe Logo](https://experienceleague.adobe.com/docs/contributor/assets/adobe_standard_logo.png "Hover text")

Displayed:

Adobe Logo

NOTE: For images that should not be localized, create a separate do-not-localize folder in the assets folder. Typically, images without text or images containing only sample content would be placed there. This removes any "noise" from the assets folder and reduces the amount of questions.

Code blocks

Markdown supports the placement of code blocks both inline in a sentence and as a separate "fenced" block between sentences. For details, see Markdown's native support for code blocks

Use back ticks ( ` ) to create inline code styles within a paragraph. To create a specific multi-line code block, add three back ticks (```) before and after the code block (called a "fenced code block" in Markdown and just a "code block" component in AEM). For fenced code blocks, add the code language after the first set of back ticks so that Markdown correctly highlights code syntax. Example: ```javascript

Examples:

This is `inline code` within a paragraph of text.

Displayed:

This is inline code within a paragraph of text.

This is a fenced code block:

function test() {
 console.log("notice the blank line before this function?");

Custom Markdown extensions

Adobe articles use standard Markdown for most article formatting, such as paragraphs, links, lists, and headings. For richer formatting, articles can use extended Markdown features such as:

  • Note blocks
  • Embedded videos
  • Do not localize
  • Component properties, such as assigning a different heading ID to a heading

Use the Markdown block quote ( > ) at the beginning of every line to tie together an extended component, such as a note. If you need to use subcomponents within components, add an extra level of block quotes (> >) for that subcomponent section. For example, a NOTE within a DONOTLOCALIZE section should begin with > >.

Some common Markdown elements such as headings and code blocks include extended properties. If you need to change default properties, add the parameters in french braces /{ /} after the component. Extended properties are described in context.

Note blocks

You can choose from these types of note blocks to draw attention to specific content:

  • [!NOTE]
  • [!TIP]
  • [!IMPORTANT]
  • [!CAUTION]
  • [!WARNING]
  • [!ADMINISTRATION]
  • [!AVAILABILITY]
  • [!PREREQUISITES]

In general, note blocks should be used sparingly because they can be disruptive. Although they also support code blocks, images, lists, and links, try to keep your note blocks simple and straightforward.

>[!NOTE]
>
>This is a standard NOTE block.

Displayed:

[!NOTE]

This is a standard NOTE block.

>[!TIP]
>
>This is a standard tip.

Displayed:

[!TIP]

This is a standard tip.

Videos

Embedded videos won't natively render in Markdown, but you can use this Markdown extension.

>[!VIDEO](https://video.tv.adobe.com/v/29770/?quality=12)

Displayed:

!VIDEO

More Like This

The "More Like This" component in AEM appears at the end of an article. It displays related links. When the article is rendered, it can be formatted the same as level-2 headings (##) without being added to the mini-TOC.

>[!MORELIKETHIS]
>* [Article 1](https://helpx.adobe.com/support/analytics.html)
>* [Article 2](https://helpx.adobe.com/support/audience-manager.html)

Displayed:

[!MORELIKETHIS]

UICONTROL and DNL

All of our Markdown help content is localized using machine translation initially. If the help has never been localized, then we keep the machine translation. However, if the help content has been localized in the past, then the machine translated content will act as a placeholder while the content is in the process of human translation.

[!UICONTROL]

During machine translation, items tagged with [!UICONTROL] are checked against a localization database for the appropriate translation. In the case that the UI is not localized, this tag will allow the system to leave the UI reference in English for that particular language (ie. Analytics references in Italian).

Example:

  1. Go to the [!UICONTROL Run Process] screen.
  2. Choose [!UICONTROL File > Print > Print All] to print all the files on your server.
  3. The [!UICONTROL Processing Rules] dialog box appears.

Source:

1. Go to the **[!UICONTROL Run Process]** screen.
1. Choose **[!UICONTROL File > Print > Print All]** to print all the files on your server.
1. The [!UICONTROL Processing Rules] dialog box appears.

NOTE: Of the three tagging options, this is the most crucial to deliver high quality and is mandatory.

[!DNL]

As a rule, we use a "Do not translate" list to tell the machine translation engines what to keep in English. The most prevalent items would be the long solution names like "Adobe Analytics", "Adobe Campaign", and "Adobe Target". However, there may be cases where we need to force the engine to use English because the term in question may be used in a specific or general way. This most obvious case would be short names for the solutions like "Analytics", "Campaign", "Target" etc. It would be difficult for a machine to understand that these are solution names and not general terms. The tag may also be used for third-party names/features which always remain in English or for shorter sections of text like a phrase or sentence which must remain in English.

Example:

  • With [!DNL Target], you can create A/B tests to find the optimal
  • Adobe Analytics is a powerful solution to collect analytics on your site. [!DNL Analytics] can also help you with reporting to easily digest that data.

Source:

* With [!DNL Target], you can create A/B tests to find the optimal 
* Adobe Analytics is a powerful solution to collect analytics on your site. [!DNL Analytics] can also help you with reporting to easily digest that data.

Gotchas and troubleshooting

Alt text

Alt text that contains underscores won't be rendered properly. For example, instead of using this:

![Settings_Step_2](/assets/settings_step_2.png)

OUr best practice is to use hyphens (-) instead of underscores (_) in filenames.

![Settings-Step-2](/assets/settings-step-2.png)

Apostrophes and quotation marks

If you copy text into a Markdown editor, the text might contain "smart" (curly) apostrophes or quotation marks. These need to be encoded or changed to basic apostrophes or quotation marks. Otherwise, you end up with odd characters like this when the file is published: It’s

Here are the encodings for the "smart" versions of these punctuation marks:

  • Left (opening) quotation mark:
  • Right (closing) quotation mark:
  • Right (closing) single quotation mark or apostrophe:
  • Left (opening) single quotation mark (rarely used):

Angle brackets

If you use angle brackets in text (not code) in your file--for example, to denote a placeholder--you need to manually encode the angle brackets. Otherwise, Markdown thinks that they're intended to be an HTML tag.

For example, encode <script name> as <script name>

Ampersands in titles

Ampersands (&) aren't allowed in titles. Use "and" instead, or use the & encoding.

See also

Markdown resources

CSS Selectors

CSS Selectors

To select DOM elements in CSS using selector.

Tag Selector

a {
  color: black;
}

h1 {
  font-size 24px;
}

Single selector

Selector Description
article Selects the element with the article tag
.post Selects all elements with the post class
#nav Selects the elements with the nav Id
div.row Selects all elements with the div tag and the row class
[hidden="true"] Selects all elements with the hidden attribute with a value of true

Note: Wildcard selector can be used to select all DOM elements.

Combine selector

Selector Description
div li DOM descendant combinator. All li tags that are a child of div tags
div.row * Selects all elements that are descendant (or child) of the elements with div tag and row class
div > li Difference combinator. Select direct descendants
div + li the adjacent combinator. It selects the element that is immediately preceded by the former element. In this case, only the first li after each div.
div, li Selects all li elements and all div elements.
div - li The sibling combinator. Selects li element following a div element.

Pseudo-selectors

Position of an element

Selector Description
:first-child Target the first element immediately inside (or child of) another element
:last-child Target the last element immediately inside (or child of) another element
:nth-child() Target the nth element immediately inside (or child of) another element. Admits integers, even, odd, or formulas
div:not(.name) Selects all div elements that are not of the .name class
::after Allows inserting content onto a page from CSS, instead of HTML. While the end result is not actually in the DOM, it appears on the page as if it is. This content loads after HTML elements.
::before Allows inserting content onto a page from CSS, instead of HTML. While the end result is not actually in the DOM, it appears on the page as if it is. This content loads before HTML elements.

State of an element

Selector Description
:hover selects an element that is being hovered by a mouse pointer
:focus selects an element receiving focus from the keyboard or programattially
:active selects an element being clicked by a mouse pointer
:link selects all links that have not been clicked yet
:visited selects a link that has already been clicked

Example

The :nth-child can use pattern, such as odd, even, An+B

a:nth-child(3n) {
  /* Css goes here */
}