For user confirmation, is it more standard to use "Y" or "N" to denote continuing execution?

Question

This is a question about best practice, not a specific language/ syntax question.

When requesting user confirmation, e.g. Y/N to either continue execution despite some risky condition or exit to fix said condition, is it preferable to use Y or N for continue?

Obviously, that will depend on the phrasing of the question. For example, in a script I'm working on right now, I check a certain directory for a certain type of file that ideally should not be there, although it is not catastrophic if it is. If I find any I warn the user and give them the option to either quit so they can delete them or continue execution anyway. I can get the user's input using at least two phrasings:

Option 1:

"There are some files that should be deleted. Do you want to delete them? Hit Y to quit so you can delete them, or N to continue execution."

Option 2:

"There are some files that should be deleted. Do you want to continue execution? Hit Y to continue, or N to quit so you can delete them."

I'm wondering which of the above options will reduce the likelihood that a frustrated or tired user who is not paying attention will opt to continue execution despite the risks.

I.e. if a user is going to somewhat randomly pick Y or N, and there is some known propensity of the "average user" to randomly pick one over the other, I'd like to make quitting the more likely option to be selected in such a case.

PS: I have no idea how to tag this question, and I don't see a "best practices" tag.

Answer 1

Don't use "Yes" and "No" for confirmation questions. In many cases, it works, but sometimes it breaks. Then, you're forced to deviate from the usual, making the case even more complicated.

Do not use "Cancel" for the same reason. That'll end up in the user needing to cancel a cancellation. Don't laugh, I've seen them.

I recommend to put the opposite actions on the buttons. And don't put negations in there - sorry: Do put positive, unnegated actions there. Humans are known to be really bad when it comes to negations.

So what about: "There are some files to delete. [Delete] [Keep]"?

Answer 2

Vendors to routinely use the word 'continue' in command prompts, with a [Y/n] to indicate the hopefully obvious options:

Continue? [Y/n]

Commonly the first letter is capitalized and indicates the expected or default outcome. Vendors typically accept 'y', 'yes', 'n' and 'no' in a case insensitive way.

---

In your case the user isn't continuing anything. However, you could abuse the above convention by doing the following:

Continue deleting unnecessary files? [Y/n]

I would expect users to delete the files with the above prompt. I did carefully choose the word 'abuse', though; I expect you to care about your users' experience and not your convenience as a software developer.

Answer 3

I like the way gkrellm does it. They go with the usual Y to continue, but explain the risk in the prompt.

Should we discombobulate your thingamajig? This is usually safe, but has been known to cause instability on systems with an AGP graphic card. Y/n:

I don't know about other users, but for me, this is enough to read before mindlessly hitting "Y". Note that I am doing this during a lengthy and boring OS reinstall, so it seems to work even under adverse conditions. You can also see if you can make the warning more attention catching through visual design.

You can also ask the user to enter a capital Y for risky decisions, normal y for non-risky ones. (This is assuming you have a keyboard prompt; your wording "hit Y" makes me think you may have one).