how to reinstall angular cli code example

Example: create angular project cli version 8

#Angular 2:the last RC version before switching to angular 4 as far as I can tell — based on this and the next version now depends on angular
npm install @angular/[email protected] 
ng new angular2app

#Angular 4: the last CLI version before angular 5
npm install @angular/[email protected] 
ng new angular4app

#Angular 5: the last CLI version before 6
npm install @angular/[email protected] 
ng new angular5app

#Angular 6: the last CLI version before 7
npm install @angular/[email protected] 
ng new angular6app 

# Angular 7: (the last CLI version before 8
npm install @angular/[email protected] 
ng new angular8app 

#Angular 8: the last CLI version before 9
npm install @angular/[email protected] 
ng new angular8app 

#Angular 9: not last CLI version 9 
npm install @angular/[email protected] 
ng new Angular9App