February of 2022

Introduction ⚑

New: Xprop.

You can use xprop to get the name and details of any running graphic application by clicking on it.

Computer Science⚑

DBMS⚑

Database Normalization ⚑

New: Add definitions and examples.

GNULinux⚑

FFmpeg ⚑

New: Concatenate and convert files.
```
ffmpeg -i "concat:1.ogg|2.ogg" out.mp3
```
New: Cropping.
```
ffmpeg -ss 30 -t 70 -i inputfile.mp3 outputfile.mp3
```
- -ss refers to the starting time.
- -t is the duration after the starting time to consider.

MarkDown ⚑

New: Disable specific rule for a block.

<!-- markdownlint-disable MD033 -->
<figure markdown>
  ![Domain model](img/domain_model.png){ loading=lazy }
  <figcaption>Proposed model.</figcaption>
</figure>
<!-- markdownlint-enable MD033 -->

MkDocs ⚑

New: Image with caption.

<!-- markdownlint-disable MD033 -->
<figure markdown>
  ![Domain model](img/domain_model.png){ loading=lazy }
  <figcaption>Proposed model.</figcaption>
</figure>
<!-- markdownlint-enable MD033 -->

PostgreSQL ⚑

New: Check that a string is a valid timezone.

Use the constraint CHECK (now() AT TIME ZONE timezone IS NOT NULL). For example:

CREATE TABLE locations (
    location_id SERIAL PRIMARY KEY,
    name TEXT,
    timezone TEXT NOT NULL CHECK (now() AT TIME ZONE timezone IS NOT NULL)
);

PulseAudio ⚑

New: Restart PulseAudio.
```
pulseaudio -k
```

Programming⚑

Jinja ⚑

New: Accessing the parent Loop.

The special loop variable always points to the innermost loop. If it’s desired to have access to an outer loop it’s possible to alias it:

<table>
{% for row in table %}
  <tr>
  {% set rowloop = loop %}
  {% for cell in row %}
    <td id="cell-{{ rowloop.index }}-{{ loop.index }}">{{ cell }}</td>
  {% endfor %}
  </tr>
{% endfor %}
</table>

NGINX ⚑

New: Support named routes.

To support named routes (e.g., APP_HOST/some/route), add the following configuration to the host configuration file:
```
location / {
    try_files $uri $uri/ /index.html;
}
```
Otherwise NGINX will return 404 when queried for a named route since the corresponding file won't exist in the root directory.

pip ⚑

New: Uninstall all packages.
```
pip freeze | xargs pip uninstall -y
```

Media⚑

Books⚑

Atlas Shrugged ⚑

New: Atlas Shrugged 1957 novel by Ayn Rand.

Atlas Shrugged is a 1957 novel by Ayn Rand. It contains Rand's most extensive statement of Objectivism. The book depicts a dystopian United States in which private businesses suffer under increasingly burdensome laws and regulations.

The book is more than a thousand pages long. There are audiobooks (~60h long) and a movie divided in three parts.

The Problem of Political Authority ⚑

New: The Problem of Political Authority.

Modern states commonly deploy coercion in a wide array of circumstances in which the resort to force would clearly be wrong for any private agent. What entitles the state to behave in this manner? And why should citizens obey its commands? This book examines theories of political authority, from the social contract theory, to theories of democratic authorization, to fairness- and consequence-based theories. Ultimately, no theory of authority succeeds, and thus no government has the kind of authority often ascribed to governments.

The author goes on to discuss how voluntary and competitive institutions could provide the central goods for the sake of which the state is often deemed necessary, including law, protection from private criminals, and national security. An orderly and livable society thus does not require acquiescence in the illusion of political authority.