YesNo Shell Command

yesno

#!/bin/bash

if [[ "--help" = "$1" ]]; then
  printf "Usage: ${0} [Message] [Yes] [No] [Yy]\n"
  printf "  Message - Defaults to \"Are you sure? \"\n"
  printf "            (notice the space at the end)\n"
  printf "  Yes     - Positive message defaults to Yes\n"
  printf "  No      - Negative message defaults to No\n"
  printf "  Yy      - Letters to use for possitive message\n\n"
  printf "  Positive messages exit with 0, Negative\n"
  printf "  messages exit with 1. Use \$\? to check value\n"
  exit 0
fi

read -p "${1-Are you sure? }" -n 1 -r
if [[ $REPLY =~ ^[${4-Yy}]$ ]]; then
  printf "\x1b[1D${2-Yes}\n"
  exit 0
else
  printf "\x1b[1D${3-No}\n"
  exit 1
fi

The command is configurable for output if you need to ask other binary questions. Simply provide the characters for the first / positive answer at the end. Yy checks for both uppercase and lowercase y. Checking for a positive answer is as simple as

if [[ "${?}" -eq 0 ]]; then
  printf "true\n"
else
  printf "false\n"
fi