debit cards?

I am still in the US and use a debit card for almost any transaction I ever make. Usually, I have about two dollars cash in my wallet and that's it .

My question is...is debit card use the same or almost in the UK? For example, when I go shopping, out to eat, etc. will I be able to just pay for basically anything with my debit card? Or do most people use cash?

If anything, they're more common here. I couldn't believe the first time I saw a London cab with a card slot

Definitely very common here.  My DH lives a mostly cash-free life, and I always like to have at least a few pounds on me...cash machines abound and I only ever rarely look nervously around when I'm out anywhere wondering if they take debit cards - they do!

I hardly ever use cash.  I have a debit card and a credit card.  Most places will take either but I have found some places that won't take one or the other.

It does depend, a little bit, on where you "normally" spend your money.  There are a number of shops/restaurants around us (Manchester, near curry mile) that operate on a cash only system.  Obviously, Tesco will take debit, and Lidl, but if you shop or eat at some of the more random/smaller places, you will need the cash.

It's rare to find a place that doesn't accept cards, even in the depths of wildest Somerset.  The chip-and-pin cards they use here are incredibly quick and easy.  I do keep a little cash handy, but find myself using my card quite a lot. 

Some places have a 5 quid minimum for debit card payments, I try to keep a few pounds on hand just in case.

One difference is that there are more types of debt cards.  In the US, all visa or mastercard debit cards are basically the same.  In the UK, there is solo, visa electron, visa debt, and maestro.  Some places will take visa debt and maestro but not visa electron or solo.  Ryanair changes difference fees for visa electron versus visa debt.  Some cards are also cheque guarantee cards.