I have actually used a knife to open cans for months on end. I couldn’t be bothered to buy a new can opener.

It was a cheap kitchen knife, it pretty much ruined it after a few months, (although I’m sure someone with patience and a whet stone could have brought it back to life.) it’s totally doable and far easier than you might think. Kinda messy tho.

The moral of the story is buy a can opener.