Handy yes/no prompt for little ruby scripts

yesno.rb

# This is a reasonably well-behaved helper for command-line scripts needing to ask a simple yes/no question.
# It optionally accepts a prompt and a default answer that will be returned on enter keypress.
# It keeps asking and echoes the answer on the same line until it gets y/n/Y/N or enter.
# I tried to get Highline to behave like this directly, but even though it's sophisticated, I didn't like the result.
# This isn't especially elegant, but it is straightforward and gets the job done.

require 'highline/import'
def yesno(prompt = 'Continue?', default = true)
  a = ''
  s = default ? '[Y/n]' : '[y/N]'
  d = default ? 'y' : 'n'
  until %w[y n].include? a
    a = ask("#{prompt} #{s} ") { |q| q.limit = 1; q.case = :downcase }
    a = d if a.length == 0
  end
  a == 'y'
end

puts yesno("Do it?", true)

I used this instead:

require 'highline/import'
confirm = ask("Do it? [Y/N] ") { |yn| yn.limit = 1, yn.validate = /[yn]/i }
exit unless confirm.downcase == 'y'

I don't know if this was in HighLine when the above answers were posted, but this is now even easier:

exit unless HighLine.agree('This will drop the User table. Do you want to proceed?')

The docs for #agree

if you don't want to use highline and your shell supports it, you could also do something like this:

printf "\033[31mWARNING -  press 'y' to continue: "
prompt = STDIN.gets.chomp
return unless prompt == 'y'

@lfender6445 This red colour thing is buggy - it is not ended properly. At least on Linux, on interupted/crashed progams it will stay in terminal (untested in other situations).

@matkoniecz, cause format wasn't cleared. For those to come:
The printf "\033[31mWARNING - press 'y' to continue: "
should be:
The printf "\033[31mWARNING - press 'y' to continue: \033[0m"
if you want red color only in the message.

FYI \e also works as shorthand for \033
printf "\e[31m#{question} - press 'y' to continue: \e[0m"

You can also just do
puts "press 'y' to continue:".red

If you do what @tweissin-pillpack suggests, you'll also want to require 'colored'