Gas piping to a dryer is NOT supposed to be installed by your husband, a friend or anyone else but a professional.
Case in point the dryer I saw in Selden NY last Sunday. Someone installed a flexible copper tube to the dryer, and this is beyond a poor installation, and into the realm of stupidity!
Does your dryer shake and shimmy when its operating? Of course - they all do to a certain degree.
If you take copper tubing like what you see in the picture below and bend it back and forth a few times, it breaks. The area where it breaks becomes what is known as 'work-hardened' and in this case a gas leak could occur.
If enough gas is present and your boiler or water heater fires, guess what? Ka-Boom!
This is just one of the many things inspectors find regularly, so make sure your dryer does NOT have copper tube for a gas line, or you could become 'disenfranchised' completely! -Ray