Connect new gas dryer to an old 15/16” gas pipe
Remove the flare fitting from the 1/2" pipe and get a 1/2" hose with 1/2" FIP fittings on each end similar to the hose pictured below. If there isn't a gas shutoff valve for that section of pipe, you'll need to install one. Use pipe joint compound or gas rated Teflon tape.



Many locations do not allow people to connect their own gas appliances but require them to contact the gas company for the installation. 
This is for your safety. Even if it's not required it's a good idea to have the gas company do it. They will check for leaks and the safety of other connections.