What is the difference between && and ; in bash or

Question

What is the difference between && and ; in bash or command? Eg:

~$ echo one && echo two

And

~$ echo one ; echo two

Answer 1

~$ echo one && echo two

This runs the 2. command only if the first command succeeds.

~$ echo one ; echo two

This always runs the 2. command.

~$ echo one || echo two

This runs the 2. command only if the first command fails.

A command is considered successful if its exit code is 0, and considered failed if its exit code is != 0.