"Do not worry, be happy."

[Odessa Dawn]

Do not worry, be happy.

Do not worry; be happy.
Do not worry: be happy.

Would either the punctuation mark(s?) (the semicolon or/and colon) replace the comma?

 

[Rover_KE]

A semicolon or a colon should replace the comma.

 

[MikeNewYork]

I would not use a colon there.

 

[Matthew Wai]

Do not worry, be happy.

Is it a comma splice? If so, can it be replaced with a full stop and a capital 'B'?

Not a teacher.

 

[MikeNewYork]

Yes, it could, but a semicolon solves the problem.

 

[probus]

But isn't this the most important point for a learner: It can never be natural to say "Do not worry (whatever punctuation), be happy." It must invariably be "Don't worry ..." in order to be natural?

 

[MikeNewYork]

I don't agree. User's choice.

 

[Matthew Wai]

A semicolon or a colon should replace the comma.

Would there be no need to replace the comma if it was followed by the conjunction 'and'?

 

[MikeNewYork]

Based on the contrast between the two clauses, I don't think "and" would work well there.