A shell function to ask the user to answer a Yes/No question.

asking.sh

# asking() @ https://gist.github.com/np/5107721#file-asking-sh {{{
# Dependencies:
#   error() @ https://gist.github.com/np/3736727#file-error-sh
# Options:
#   --default=no  Makes No being the default (--default=yes is the default)
#   --no-slmenu   Do no use slmenu even if available
# Examples:
#   asking 'Something failed, do you still want to continue?'
#   asking --default=yes 'Next step?'
asking(){
  local default=0
  local fzf=1
  local slmenu=1
  while true; do
    case "$1" in
      --default=yes) shift;;
      --default=no)  shift; default=1;;
      --no-slmenu)   shift; slmenu=0;;
      --no-fzf)      shift; fzf=0;;
      --*)           error 1 "asking: unexpected option argument $1";;
      *)             break;;
    esac
  done
  if (( default )); then
    local prompt_answer='y/N'
    local prompt_answer_lines="$(printf 'No\nYes\n')"
  else
    local prompt_answer='Y/n'
    local prompt_answer_lines="$(printf 'Yes\nNo\n')"
  fi
  printf '\a'
  if (( slmenu )) && which slmenu >/dev/null 2>/dev/null; then
    answer="$(slmenu -i -l 2 -p "$*" <<<"$prompt_answer_lines")"
  elif (( fzf )) && which fzf >/dev/null 2>/dev/null; then
    answer="$(fzf -1 --prompt="$* " <<<"$prompt_answer_lines")"
  else
    read -p "$* ($prompt_answer)" answer
  fi

  case "$answer" in
    n|N|no|NO|No|nO) return 1;;
    y|Y|yes|YES|Yes|YEs|YeS|yES|yeS|yEs) return 0;;
    *) return $default;;
  esac
}

check-positive-asking(){
  while asking "$@"; do
    echo "Good you can try another option or hit the opposite to leave this loop"
  done
  echo "You left the loop by typing the opposite, right?"
}

check-negative-asking(){
  while true; do
    if asking "$@"; then
      break
    else
      echo "Good you can try another option or hit the opposite to leave this loop"
    fi
  done
  echo "You left the loop by typing the opposite, right?"
}

check-asking(){
  check-positive-asking 'hit y|Y|yes|YES|Yes|YEs|YeS|yES|yeS|yEs|nothing|garbage and hit RETURN'
  check-negative-asking 'hit n|N|no|NO|No|nO and hit RETURN'

  check-positive-asking --default=no 'hit y|Y|yes|YES|Yes|YEs|YeS|yES|yeS|yEs and hit RETURN'
  check-negative-asking --default=no 'hit n|N|no|NO|No|nO|nothing|garbage and hit RETURN'
}
# }}}