José Hernández doraemoncito

Setting up Pi Zero OTG - The quick way (No USB keyboard, mouse, HDMI monitor needed)

More details - http://blog.gbaman.info/?p=791

For this method, alongside your Pi Zero, MicroUSB cable and MicroSD card, only an additional computer is required, which can be running Windows (with Bonjour, iTunes or Quicktime installed), Mac OS or Linux (with Avahi Daemon installed, for example Ubuntu has it built in).
1. Flash Raspbian Jessie full or Raspbian Jessie Lite onto the SD card.
2. Once Raspbian is flashed, open up the boot partition (in Windows Explorer, Finder etc) and add to the bottom of the config.txt file dtoverlay=dwc2 on a new line, then save the file.
3. If using a recent release of Jessie (Dec 2016 onwards), then create a new file simply called ssh in the SD card as well. By default SSH i

Converting mkv to mp4 with `ffmpeg`

Essentially just copy the existing video and audio stream as is into a new container, no funny business!

The easiest way to "convert" MKV to MP4, is to copy the existing video and audio streams and place them into a new container. This avoids any encoding task and hence no quality will be lost, it is also a fairly quick process and requires very little CPU power. The main factor is disk read/write speed.

With ffmpeg this can be achieved with -c copy. Older examples may use -vcodec copy -acodec copy which does the same thing.

These examples assume ffmpeg is in your PATH. If not just substitute with the full path to your ffmpeg binary.

Single file conversion example

Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

Dockerized PostgreSQL database with OpenAPI support

Here's a quick and simple way to get up and running with a local sample PostgreSQL database with content that is also served via a RESTful interface using PostgREST and Swagger UI.

To get started you must have docker installed. Copy the text below into a file called compose.yaml

services:
    postgresql:
        image: aa8y/postgres-dataset:latest

/**
 * Computes the machine precision (also known as machine epsilon) by
 * repeatedly dividing `epsilon' by two until it is too small to add
 * to one without causing roundoff.
 * 
 * @return
 *	Computed machine precision value
 */
static double maxPrecision()

Save all links in the current Safari session to the macOS clipboard

Copy all links from Safari to the clipboard as a list of URLs in JSON format

Open automator and create an application script called safe-safari-session-to-clipboard-json.app.

Add a JavaScript step with the following content

function run(input, parameters) {

Installing and using schemacrawler for MacOS

A recipe for generating cool SQLite database diagrams with schemacrawler on MacOS

This was tested on MacOS 10.14.5 on 2019-07-16

schemacrawler is a free and open-source database schema discovery and comprehension tool. It can be invoked from the command-line to produce, using GraphViz, images/pdfs from a SQLite (or other database type) file. It can be used from the command-line to generate schema diagrams like these:

	// {{compare unicorns ponies operator="<"}}
	// I knew it, unicorns are just low-quality ponies!
	// {{/compare}}
	//
	// (defaults to == if operator omitted)
	//
	// {{equal unicorns ponies }}
	// That's amazing, unicorns are actually undercover ponies
	// {{/equal}}
	// (from http://doginthehat.com.au/2012/02/comparison-block-helper-for-handlebars-templates/)

	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;
	import org.springframework.http.HttpHeaders;
	import org.springframework.http.HttpRequest;
	import org.springframework.http.MediaType;
	import org.springframework.http.client.ClientHttpRequestExecution;
	import org.springframework.http.client.ClientHttpRequestInterceptor;
	import org.springframework.http.client.ClientHttpResponse;
	import org.springframework.util.StreamUtils;

	#
	# Keyboard Emulator Using Maker Pi Pico and CircuitPython
	#
	# References and credit to
	# - https://learn.adafruit.com/circuitpython-essentials/circuitpython-hid-keyboard-and-mouse
	#
	# Raspberry Pi Pico
	# - [Maker Pi Pico] https://my.cytron.io/p-maker-pi-pico?tracking=idris
	#
	# Additional Libraries