Pocket knives have been around for a long time, although I would guess that multitools, in the form of Swiss Army knives* or the more (to me) versatile Leatherman/Gerber type are more popular these days. I suppose it used to be pretty much exclusively a boy thing, and probably still is if you only consider people who actually carry them in pockets. One of the advantages of carrying a purse, though, is that you have room for the bulkier tools popular these days (I carry this one, which was a gift from one of my kids).
My favorite of those included in this article has to be this early Swiss Army-esque number from Rome, circa 200 AD:
Wikipedia has this Roman pocket knife, along with a modern re-construction:
And here's a switchblade from ~ 1750:
See the original article, along with lots more images,at Cool Material. More information at Art of Manliness: Every Man Should Carry a Pocket Knife, and still more here and at Wikipedia.
* Per Today I Found Out, the term “Swiss Army Knife” was coined by United States soldiers after WWII. The soldiers had trouble pronouncing the original name of “Schweizer Offiziersmesser” (Swiss Officer’s Knife) and thus began calling the multi-tool a “Swiss Army Knife”. This ultimate Swiss Army knife can be yours for a mere $1,349: