how are you doing—(also: how are you)
1. is used to ask a person whether everything is going well:
- I am not really good at showing people how I am really feeling, you know … the “how are you doing?” “Oh, I am doing okay” that stuff.
2. is used as an informal greeting when meeting people and requires no reply:
- We used to have short conversations every day, but now, it’s more of a “Hi, how are you doing?”
how do you do—is used as a formal greeting when meeting people or being introduced:
- “How do you do, Miss Ferrell? I am Miss Wright.” “How do you do.”