Following the announcement of the iPhone 5, iOS 6 GM was later released to developers. That was followed by the launch of RedSn0w 0.9.13dev4 jailbreak tool for the firmware, and now a jailbreak guide has been released.
As has been the case for the iOS 6 beta, the newly-released tethered jailbreak will not install Cydia. Its purpose is to deliver SSH access for developers. Courtesy of iDownloadBlog, the guide can be seen below in video form, as well as a step-by-step guide.
Step 1: Download RedSn0w 0.9.13dev4 (Mac and Windows) and run it.
Step 2: Place your A4 device (iPhone 4, iPod touch 4th gen) into DFU mode.
Step 3: Select Extras, and then Select IPSW, and then open the iOS 6 GM firmware for your device.
Step 4: Go back to the main page and select Jailbreak.
Step 5: Once Install SSH option is selected, proceed. Your iOS device should now be jailbroken.
Step 6: Put your iOS device back into DFU mode.
Step 7: Go back to the main page of RedSn0w and select Extras and then select “Just boot”. A tethered boot on your device will now be carried out.
Step 8: You should now be able to access your iOS device through SSH.