多选版本：

ask () {                        # $1=question $2=options
    # set REPLY
    # options: x=..|y=..
    while $(true); do
        printf '%s [%s] ' "$1" "$2"
        stty cbreak
        REPLY=$(dd if=/dev/tty bs=1 count=1 2> /dev/null)
        stty -cbreak
        test "$REPLY" != "$(printf '\n')" && printf '\n'
        (
            IFS='|'
            for o in $2; do
                if [ "$REPLY" = "${o%%=*}" ]; then
                    printf '\n'
                    break
                fi
            done
        ) | grep ^ > /dev/null && return
    done
}

例子：

$ ask 'continue?' 'y=yes|n=no|m=maybe'
continue? [y=yes|n=no|m=maybe] g
continue? [y=yes|n=no|m=maybe] k
continue? [y=yes|n=no|m=maybe] y
$

它会将REPLY设置为y（在脚本中）。

此解决方案读取单个字符，并在yes响应时调用函数。

read -p "Are you sure? (y/n) " -n 1
echo
if [[ $REPLY =~ ^[Yy]$ ]]; then
    do_something      
fi

可以在POSIX shell中处理区域设置感知的“是/否选项”；通过使用LC_MESSAGES语言环境类别的条目，witch提供了与输入匹配的现成RegEx模式，以及本地化Yes No的字符串。

#!/usr/bin/env sh

# Getting LC_MESSAGES values into variables
# shellcheck disable=SC2046 # Intended IFS splitting
IFS='
' set -- $(locale LC_MESSAGES)

yesexpr="$1"
noexpr="$2"
yesstr="$3"
nostr="$4"
messages_codeset="$5" # unused here, but kept as documentation

# Display Yes / No ? prompt into locale
echo "$yesstr / $nostr ?"

# Read answer
read -r yn

# Test answer
case "$yn" in
# match only work with the character class from the expression
  ${yesexpr##^}) echo "answer $yesstr" ;;
  ${noexpr##^}) echo "answer $nostr" ;;
esac

编辑：正如@Urhixidur在评论中提到的：

不幸的是，POSIX只指定了前两个（yeexpr和noexpr）。在Ubuntu 16上，yestr和nostr为空。

参见：https://www.ee.ryerson.ca/~courses/ele709/susv4/xrat/V_4_xbd_chap07.html#tag_21_07_03_06

LC_消息yestr和nostr语言环境关键字以及yesstr和nostr语言信息项以前用于匹配用户的肯定和否定响应。在POSIX.1-2008中，yeexpr、noexpr、yesexpr和noexpr扩展正则表达式已取代它们。应用程序应该使用通用的基于语言环境的消息传递工具来发出包含所需响应示例的提示消息。

或者使用Bash方式的区域设置：

#!/usr/bin/env bash

IFS=$'\n' read -r -d '' yesexpr noexpr _ < <(locale LC_MESSAGES)

printf -v yes_or_no_regex "(%s)|(%s)" "$yesexpr" "$noexpr"

printf -v prompt $"Please answer Yes (%s) or No (%s): " "$yesexpr" "$noexpr"

declare -- answer=;

until [[ "$answer" =~ $yes_or_no_regex ]]; do
  read -rp "$prompt" answer
done

if [[ -n "${BASH_REMATCH[1]}" ]]; then
  echo $"You answered: Yes"
else
  echo $"No, was your answer."
fi

使用语言环境提供的regexp来匹配答案。

要翻译剩余的消息，请使用bash--dump po string scriptname输出po字符串以进行本地化：

#: scriptname:8
msgid "Please answer Yes (%s) or No (%s): "
msgstr ""
#: scriptname:17
msgid "You answered: Yes"
msgstr ""
#: scriptname:19
msgid "No, was your answer."
msgstr ""

针对其他人：

您不需要在BASH4中指定大小写，只需使用'，，'使var小写即可。此外，我强烈不喜欢将代码放在读取块内，获取结果并在读取块IMO外处理它。还包括一个“q”表示退出IMO。最后，为什么键入“yes”只需使用-n1并按y。

示例：用户可以按y/n和q退出。

ans=''
while true; do
    read -p "So is MikeQ the greatest or what (y/n/q) ?" -n1 ans
    case ${ans,,} in
        y|n|q) break;;
        *) echo "Answer y for yes / n for no  or q for quit.";;
    esac
done

echo -e "\nAnswer = $ans"

if [[ "${ans,,}" == "q" ]] ; then
        echo "OK Quitting, we will assume that he is"
        exit 0
fi

if [[ "${ans,,}" == "y" ]] ; then
        echo "MikeQ is the greatest!!"
else
        echo "No? MikeQ is not the greatest?"
fi

echo "Please enter some input: "
read input_variable
echo "You entered: $input_variable"

我为回答是/否问题编写了一个小脚本：https://github.com/optimistiCli/getans

例子：

#!/bin/bash

if ! getans.sh 'Shall we proceed?' y ; then
    echo "User said “NO”"
    exit 1
fi

echo "User said “YES”"
# do something usefull
exit 0

直接链接：https://github.com/optimistiCli/getans/raw/main/getans.sh