why subtraction return - symbol

Question

I have a problem with a simple subtraction but I don\'t understand what\'s wrong.

My code :

start= date +%s%N | cut -b1-13
#Treatment...
end= date +%s%N         


        

Answer 1

You didn't assign to the variables. You must not have spaces around the equals sign.

Also, you're doing it wrong.

start=$(date +%s%N | cut -b1-13)