Used in "be used to" and "get used to" mean "familiar with someone or something through experience" in both the cases.
I'm not used to eating so much at lunchtime.
I found the job tiring at first but I soon got used to it.
As linking verb, get means "to reach a particular state or condition."
You'll soon get used to the climate here.
Compare the following sentences.
She is used to getting what she wants from her parents. It still is happening.
I was used to having an headache after eating fishes. It doesn't happen anymore.
She left the television on while she was sleeping. I got used to this after a while. I gradually become used to this; nothing is said about this being still true.
Get used to this: After you do it, their voices will be less boring than birds singing at 5 AM every day.
Notice that used to has a different meaning; it is used when describing an action or state of affairs that was done repeatedly or existed for a period in the past.
This road used to be a dirt track.
I used to give him lifts home.
The difference is that be/get used to describes something with which you are familiar through experience. In most of the cases, you cannot replace one with the other one.
This road was used to be a dirt track.