Drupal 8 Hook System

Hooks allow modules to alter the drupal core behavior or another module. Hooks are discovered and called at specific times to alter or add to the base behavior or data (invoking the hook). Each hook has a name start with hook_ (Ex; hook_menu()).

Create a new Plugin Type in Drupal 8

Example from Drupal 8 example module, Thank you.
See the Drupal 8 'Example' contrib module for full details and source

Module name : 'plugin_type_example'

 

Drupal 8 introduces the concept of services to decouple reusable functionality and makes these services pluggable and replaceable by registering them with a service container.

 

Plugins are small pieces of functionality that are swappable. Plugins that perform similar functionality are of the same plugin type.

Link : https://www.drupal.org/developing/api/8/plugins

Vi - Vim Ccommand line editor's Usefull commands

vim filename.txt (to create or open a file)