How do you say hello in greek and how is it written?

The most common way to say "hello" in Greek is Γεια σας (`Yá sas`) but here are a few different greetings based on the time of day:

- Γεια σας (`Yá sas`): good day / hello during the day

- Καλημέρα (`Kaliméra`): good morning

- Καλησπέρα (`Kalispéra`): good evening until evening and before midnight

- Καληνύχτα (`Kalinyhta`): good night, when you go to bed