a1mzone

Develop

Java - Spring Framework (1st release was in 2002)
Relational DB - PostgreSQL (Started in 1986, most populat open source DB with several TB deployments, Yahoo in fact had a 2PB deployment in 2008)
Mobile - React / Flutter / Cordova - maybe Xamarin

Big Data

Hadoop (2002, based on Google File System paper, in 2007, Yahoo successfully tests Hadoop on a 1000 node cluster, a year later Apache Software Foundation successfully tested a 4000 node cluster)
Accumullo (Based on Google Bigtable, created in 2008 by US National Security Agency)

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Basic ZSH Setup

sudo apt install git curl zsh

sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

sed 's/robbyrussell/gnzh/' -i ~/.zshrc

# general

alias esrc='code ~/source/ohmyconfig/zshrc_config'

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HELM

Install

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

Add Repo

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo add superset https://apache.github.io/superset

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GeoMesa Spark

MakePolygon

ST_MakePolygon(ST_ExteriorRing(ST_Collect(
st_makepoint(28.1833495,-26.0544965),
st_makepoint(28.1837932,-26.0604524),
st_makepoint(28.1833495,-26.0544965))))

PolygonFromText

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Apache Superset - Ubuntu 20.04LTS

sudo apt-get install build-essential libssl-dev libffi-dev python3-dev python3-pip libsasl2-dev libldap2-dev default-libmysqlclient-dev  libpq-dev python3-dev

mkvirtualenv -p python3.8 superset-3.8

pip install --upgrade setuptools pip

pip install apache-superset==2.0.0

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GeoHash Size

1 ≤ 5,000km × 5,000km
2 ≤ 1,250km × 625km
3 ≤ 156km × 156km
4 ≤ 39.1km × 19.5km
5 ≤ 4.89km × 4.89km
6 ≤ 1.22km × 0.61km
7 ≤ 153m × 153m
8 ≤ 38.2m × 19.1m

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BASH

Find Terminal

ps | grep $$
which 

!#/bin/terminal

Variables

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Python

Compile

git clone https://github.com/python/cpython
git checkout <version>

./configure --enable-optimizations
make -j8
sudo make altinstall

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fdisk

List logical disks and partitions

sudo fdisk -l

Partition the disk

sudo fdisk /dev/sdb

• Press n to create a partition
• Press p or l to create primary or logical partitions

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ffmpeg

Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:
ffmpeg -i input.mp3 output.wma

You can get the list of supported formats with:
ffmpeg -formats

Convert WAV to MP3, mix down to mono (use 1 audio channel), set bit rate to 64 kbps and sample rate to 22050 Hz: