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Bash内置命令（即便携式）检查TTY默认答案超时彩色问题

一小条

do_xxxx=y                      # In batch mode => Default is Yes
[[ -t 0 ]] &&                  # If TTY => Prompt the question
read -n 1 -p $'\e[1;32m
Do xxxx? (Y/n)\e[0m ' do_xxxx  # Store the answer in $do_xxxx
if [[ $do_xxxx =~ ^(y|Y|)$ ]]  # Do if 'y' or 'Y' or empty
then
    xxxx
fi

解释

[[-t 0]]&&read…=>如果TTY，调用命令读取read-n 1=>等待一个字符$'\e[1；32m…\e[0m'=>绿色打印（绿色很好，因为在白色/黑色背景上都可以阅读）[[$do_xxxx=~^（y|y|）$]]=>bash正则表达式

超时=>默认答案为否

do_xxxx=y
[[ -t 0 ]] && {                   # Timeout 5 seconds (read -t 5)
read -t 5 -n 1 -p $'\e[1;32m
Do xxxx? (Y/n)\e[0m ' do_xxxx ||  # read 'fails' on timeout
do_xxxx=n ; }                     # Timeout => answer No
if [[ $do_xxxx =~ ^(y|Y|)$ ]]
then
    xxxx
fi

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）。

read -p "Are you alright? (y/n) " RESP
if [ "$RESP" = "y" ]; then
  echo "Glad to hear it"
else
  echo "You need more bash programming"
fi

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

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

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