如何在Linux shell脚本中提示用户输入Yes/No/Cancel？

yn() {
  if [[ 'y' == `read -s -n 1 -p "[y/n]: " Y; echo $Y` ]];
  then eval $1;
  else eval $2;
  fi }
yn 'echo yes' 'echo no'
yn 'echo absent no function works too!'

一个简单的方法是使用xargs -p或gnu parallel --interactive。

我更喜欢使用xargs，因为它的行为更好，它像其他交互式Unix命令一样立即在提示符后执行每个命令，而不是在最后收集确认来运行。(你可以在完成你想要的操作后按Ctrl-C。)

例如：

echo *.xml | xargs -p -n 1 -J {} mv {} backup/

#! /bin/sh 

# For potential users of BSD, or other systems who do not
# have a bash binary located in /bin the script will be directed to
# a bourne-shell, e.g. /bin/sh

# NOTE: It would seem best for handling user entry errors or
# exceptions, to put the decision required by the input 
# of the prompt in a case statement (case control structure), 

echo Would you like us to perform the option: "(Y|N)"

read inPut

case $inPut in
    # echoing a command encapsulated by 
    # backticks (``) executes the command
    "Y") echo `Do something crazy`
    ;;
    # depending on the scenario, execute the other option
    # or leave as default
    "N") echo `execute another option`
    ;;
esac

exit

回复其他人：

BASH4中不需要指定大小写，只需使用',,'将变量转换为小写即可。此外，我强烈反对在read块内放置代码，最好在read块外处理结果。还可以包含一个“q”以退出程序。最后，为什么要输入“yes”，只需使用-n1并按y键即可。

示例：用户可以按y / n键，也可以按q键退出。

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

使用 PyInquirer 实现的一个Python单行代码替代方案

python3 -c 'import PyInquirer; print(PyInquirer.prompt([{"type":"confirm", "message":"Do you want to continue?", "name":"r"}]).get("r"))'

该程序支持是/否/取消 (按键intr, CTRL+C)。

confirm() {
  local ans IFS=;
  while read -rp "$1" -n1 ans;
  do printf '\n';
    case $ans in [Yy]) return 0;;
      [Nn]) return 1;;
    esac;
  done;
}; ## Usage: if confirm "Are you sure? "; then ...

if confirm "Does everything look ok...reboot now? [Y/n]"; then
  echo "rebooting..."
  sleep 5
  reboot
fi

#!/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

#!/usr/bin/env bash

set -eu -o pipefail

function prompt() {
    read -p "$* [Y/n]: " yn
    if [[ $yn = "y" || $yn = "Y" ]]; then
        return 0
    else 
        return 1
    fi
}

prompt "one liner?" && echo "YES" || echo "NO"

if prompt "in an if?"; then
    echo "YES"
else
    echo "NO"
fi

我创建了这个函数，以便由我所有需要是yes/no/true/false/default响应的bash脚本调用，因为我厌倦了每次需要响应时都重新创建代码。

它具有可设置的问题和可设置的默认答案，对于默认响应也有错误处理（意味着您可以更改默认答案），同时捕获未被引号包围的问题。我意识到这比原始帖子要求的更详细，但在任何bash 4+中，它应该是完全可移植的。它也可以作为if语句中的命令使用，因为它返回0或1，并详细说明了答案以进行调试。

用法：confirm -d n "是否是答案？"

返回输出：

user@ubuntu# confirm -d n "Is this the answer?"
Is this the answer? [Y/n:default=N]: 
default no

这是函数：

confirm(){
  errorMsg='
  Too many arguments.
  use "-d" as the first option to set default value.
  If providing a question, remember to quote the line to prevent each word from being an argument.
  example: confirm -d n "Is this the answer?"'
  defSet=false
  while [ "$#" -ge 1 ]; do
    if [ "$#" -ge 2 ]; then
      confirmArg=$1
      if [[ "$confirmArg" = '-d' ]]; then
        confirmArgCheck=$2
        errorMsg2="
        '${confirmArgCheck}' is not a valid default return value.
        Must be [Yy]es/[Nn]o or [Tt]rue/[Ff]alse"
        case $confirmArgCheck in
          [Yy]*|[Tt]*)
            regex1="[Yy][Ee]?[Ss]?$"
            regex2="[Tt][Rr]?[Uu]?[Ee]?$"
            if [[ "$confirmArgCheck" =~ $regex1 ]]; then
              unset regex1 && unset regex2
              confirmArgVal=Y
            elif [[ "$confirmArgCheck" =~ $regex2 ]]; then
              unset regex1 && unset regex2
              confirmArgVal=Y
            else
              unset regex1 && unset regex2
              echo "$errorMsg2"
              return 1
            fi
            ;;
          [Nn]*|[Ff]*)
            regex1="[Nn][Oo]?$"
            regex2="[Ff][Aa]?[Ll]?[Ss]?[Ee]?$"
            if [[ "$confirmArgCheck" =~ $regex1 ]]; then
              unset regex1 && unset regex2
              confirmArgVal=N
            elif [[ "$confirmArgCheck" =~ $regex2 ]]; then
              unset regex1 && unset regex2
              confirmArgVal=N
            else
              unset regex1 && unset regex2
              echo "$errorMsg2"
              return 1
            fi
            ;;
          *)
            echo "$errorMsg2"
            return 1
            ;;
        esac
        defSet=true
        shift 2
      else
        if [[ ! "$*" == *"-d"* ]]; then
          shiftmore="$#"
          quest="$@"
          questSet=true
          shift "$shiftmore"
        else
          echo "$errorMsg"
          return 1
        fi
      fi
    else
      quest=$1
      questSet=true
      shift 1
    fi
  done
  if [[ ! $defSet = true ]]; then
    confirmArgVal=Y
  fi
  if [[ ! $questSet = true ]]; then
    quest='Answer?'
  fi
  while true; do
    read -r -p "${quest} [Y/n:default=$confirmArgVal]: " yn
    case $yn in
      [Yy]*)
        unset quest
        unset yn
        unset confirmArgVal
        echo "answered yes"
        return 0
        ;;
      [Nn]*)
        unset quest
        unset yn
        unset confirmArgVal
        echo "answered no"
        return 1
        ;;
      "")
        unset quest
        unset yn
        if [[ "$confirmArgVal" = 'Y' ]]; then
          unset confirmArgVal
          echo "default yes"
          return 0
        else
          unset confirmArgVal
          echo "default no"
          return 1
        fi
        ;;
      *)
        echo "Please answer yes or no."
        ;;
    esac
  done
}