My beer is close to being done fermenting. There is 5 gallons of it and I was wondering if instead of putting it into a bunch of bottles I could put it into 5 glass jugs that have rubber corks?
In principle beer can be put and stored in "a glass jug with a rubber cork". However it might be difficult to naturally carbonate the brew to any degree in a rubber stopped glass jug. Any pressure build up would tend to "self vent" unless the stopper was firmly wired on. Some types of rubber stopper can also affect the taste of any beer they come into prolonged contact with. So I would not recommend a glass jug used for anything other than temporary storage of beer. For example - to decant into prior to pouring into a glass.
A better but cheap option might be to re-use 500mL/1L plastic fizzy drinks bottles (usually screw top PET plastic bottles). They are shatter resistant and will keep fizzy beer for at least 4 months and probably slightly longer.
I have put my beer into 2 litre growlers before with a locking cap which was a nice way of bottling it quickly, although it does come with its down sides, for example it's hard to chill in a standard fridge without mixing in the sediment and once you open the bottle you are sort of locked into drinking 2L of it, which isn't always a bad thing :).
As for a straight cork I think you really would run the risk of some explosions. You could use champagne corks with a cage.
1 gallon glass jugs made for juice / wine are not rated for any significant pressure. While they work great for starters or small batch fermentors I would not bottle condition in them or fill with carbonated beer.
They have too much surface area for the needed 12 psi for carbonation and will fail.
I would use PET 2 liter soda bottles instead.