sticky bit

https://en.m.wikipedia.org/wiki/Sticky_bit

The sticky bit can be set using the chmod command and can be set using its octal mode 1000 or by its symbol t (s is already used by the setuid bit). For example, to add the bit on the directory /usr/local/tmp , one would type chmod +t /usr/local/tmp .

The best Linux screen recorder

The best Linux screen recorder

https://itsfoss.com/best-linux-screen-recorders/
sudo apt install kazam

sudo add-apt-repository ppa:obsproject/obs-studio
sudo apt update
sudo apt install obs-studio

sudo apt install simplescreenrecorder

sudo apt install gtk-recordmydesktop

sudo apt install vokoscreen

sudo add-apt-repository ppa:soylent-tv/screenstudio
sudo apt update
sudo apt install screenstudio

sudo add-apt-repository ppa:fossproject/ppa
sudo apt update
sudo apt install green-recorder

sudo add-apt-repository ppa:peek-developers/stable
sudo apt update
sudo apt install peek


https://alternativeto.net/software/simplescreenrecorder/

https://alternativeto.net/software/open-broadcaster-software/

https://community.udemy.com/t5/First-time-Course-Creation/Linux-alternative-to-Camtasia/td-p/14451

https://www.slant.co/options/8066/alternatives/~camtasia-alternatives

HCL Hashicorp Configuration Language and Terraform

HCL is a Hashicorp configuration language. 

It's also part of a broader ecosystem of tools built by cloud automation company HashiCorp that largely center around Terraform. 

Terraform is an infrastructure-as-code tool that makes it easier to define and manage your cloud infrastructure. HCL is simply the syntax that allows you to better leverage its capabilities. It gives you a significant degree of control over your infrastructure in a way that's more 'human-readable' than other configuration languages such as YAML and JSON.

HCL and Terraform are both important parts of the DevOps world.

More:

https://hub.packtpub.com/what-is-hcl-hashicorp-configuration-language-how-does-it-relate-to-terraform-and-why-is-it-growing-in-popularity/ 

Functional interfaces

Functional interfaces - examples:

@FunctionalInterface 

interface Walkable {

    public String walk();

}

@FunctionalInterface  

interface Sayable{  

    void say(String msg);

} 

and after using:

        Walkable walkWithLambda = () -> {

            return "I want to walk around.";

        };

        walkWithLambda.walk();

        Sayable sayWithLambda = (msg) - > {

            System.out.println(msg);

        };

        sayWithLambda.say("I want to say something important!");

https://dzone.com/articles/introduction-functional-1

https://docs.oracle.com/javase/8/docs/api/?java/lang/FunctionalInterface.html

https://stackoverflow.com/questions/36881826/what-are-functional-interfaces-used-for-in-java-8

https://www.javaguides.net/2018/07/java-8-functional-interfaces.html

https://www.javaguides.net/2018/11/java-functionalinterface-annotation.html

https://github.com/RameshMF/java-8-tutorial/tree/master/src/com/ramesh/java8/functionalInterfaces

Elastisearch once again

Elastisearch once again

Elasticsearch is a search engine based on the Lucene library. It provides a distributed, multitenant-capable full-text search engine with an HTTP web interface and schema-free JSON documents. Elasticsearch is developed in Java.

Elasticsearch is a distributed, RESTful highly scalable open-source full-text search and analytics engine capable of solving a growing number of use cases. It allows you to store, search, and analyze big volumes of data quickly and in near real time. Related to other products as Kibana and Logstash...

In application.properties we can write the information to connect to H2 database (in-memory, java-based fast and easy database for rapid development):
spring.datasource.url=jdbc:h2:mem:simulationdb;INIT=RUNSCRIPT FROM '/home/kris/KD/h2-create-insert.sql';DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
spring.datasource.driverClassName=org.h2.Driver

Now we can log in and check at the console:
http://localhost:8080/h2

Further information:

https://pl.wikipedia.org/wiki/Elasticsearch

https://www.elastic.co/guide/index.html

https://docs.spring.io/spring-data/elasticsearch/docs/current/api/org/springframework/data/elasticsearch/annotations/package-tree.html

https://docs.spring.io/spring-data/elasticsearch/docs/current/api/org/springframework/data/elasticsearch/annotations/Document.html

https://github.com/spring-projects/spring-data-elasticsearch/blob/master/src/main/java/org/springframework/data/elasticsearch/annotations/Document.java

https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-elasticsearch-specification.html