Stripped male connector from dryer
It depends on how badly damaged the pipe is, but it can be re-threaded with a pipe die.  I would replace the pipe nipple coming out of the gas valve.  I would look at how the gas valve is mounted to the dryer before trying to remove the damaged nipple.  Some have poor mounting and could damage the gas valve.  You may need to remove the valve before removing the nipple from it.  With either option, I would test for leaks by spraying soapy water on the joints after you turn the gas back on and looking for bubbles.