How many application installed on Linux

Identify all Linux codes that accessible from terminal

https://www.youtube.com/watch?v=p6VGmXlTEYs

Resetting the root password Kali Linux

How To Change Login Password Kali Linux 

https://www.youtube.com/watch?v=CLp8hHSmZHk

Adding a non root user kali linux

How to add non-root user for Kali Linux

https://www.youtube.com/watch?v=V6mRcMGqMnI