我想暂停shell脚本中的输入,并提示用户进行选择。标准的是、否或取消类型问题。如何在典型的bash提示符中完成此操作?


当前回答

更通用的是:

function menu(){
    title="Question time"
    prompt="Select:"
    options=("Yes" "No" "Maybe")
    echo "$title"
    PS3="$prompt"
    select opt in "${options[@]}" "Quit/Cancel"; do
        case "$REPLY" in
            1 ) echo "You picked $opt which is option $REPLY";;
            2 ) echo "You picked $opt which is option $REPLY";;
            3 ) echo "You picked $opt which is option $REPLY";;
            $(( ${#options[@]}+1 )) ) clear; echo "Goodbye!"; exit;;
            *) echo "Invalid option. Try another one.";continue;;
         esac
     done
     return
}

其他回答

在shell提示符下获取用户输入的最简单和最广泛的方法是read命令。说明其用途的最佳方法是简单的演示:

while true; do
    read -p "Do you wish to install this program? " yn
    case $yn in
        [Yy]* ) make install; break;;
        [Nn]* ) exit;;
        * ) echo "Please answer yes or no.";;
    esac
done

Steven Huwig指出的另一种方法是Bash的select命令。下面是使用select的相同示例:

echo "Do you wish to install this program?"
select yn in "Yes" "No"; do
    case $yn in
        Yes ) make install; break;;
        No ) exit;;
    esac
done

使用select,您不需要清理输入–它会显示可用的选项,并键入与您的选择相对应的数字。它也会自动循环,所以如果它们提供了无效的输入,就不需要使用while true循环来重试。

此外,Léa Gris在她的回答中展示了一种使请求语言不可知的方法。调整我的第一个示例以更好地服务于多种语言可能如下所示:

set -- $(locale LC_MESSAGES)
yesexpr="$1"; noexpr="$2"; yesword="$3"; noword="$4"

while true; do
    read -p "Install (${yesword} / ${noword})? " yn
    if [[ "$yn" =~ $yesexpr ]]; then make install; exit; fi
    if [[ "$yn" =~ $noexpr ]]; then exit; fi
    echo "Answer ${yesword} / ${noword}."
done

显然,其他通信字符串在这里仍然没有翻译(Install,Answer),这需要在更完整的翻译中解决,但在许多情况下,即使是部分翻译也会很有用。

最后,请查看F.Hauri的优秀答案。

检查此项

read -p "Continue? (y/n): " confirm && [[ $confirm == [yY] || $confirm == [yY][eE][sS] ]] || exit 1

受到@Mark和@Myrdin的回答的启发,我创建了一个通用提示的函数

uniprompt(){
    while true; do
        echo -e "$1\c"
        read opt
        array=($2)
        case "${array[@]}" in  *"$opt"*) eval "$3=$opt";return 0;; esac
        echo -e "$opt is not a correct value\n"
    done
}

这样使用:

unipromtp "Select an option: (a)-Do one (x)->Do two (f)->Do three : " "a x f" selection
echo "$selection"

是/否/取消

作用

#!/usr/bin/env bash
@confirm() {
  local message="$*"
  local result=''

  echo -n "> $message (Yes/No/Cancel) " >&2

  while [ -z "$result" ] ; do
    read -s -n 1 choice
    case "$choice" in
      y|Y ) result='Y' ;;
      n|N ) result='N' ;;
      c|C ) result='C' ;;
    esac
  done

  echo $result
}

用法

case $(@confirm 'Confirm?') in
  Y ) echo "Yes" ;;
  N ) echo "No" ;;
  C ) echo "Cancel" ;;
esac

使用干净的用户输入进行确认

作用

#!/usr/bin/env bash
@confirm() {
  local message="$*"
  local result=3

  echo -n "> $message (y/n) " >&2

  while [[ $result -gt 1 ]] ; do
    read -s -n 1 choice
    case "$choice" in
      y|Y ) result=0 ;;
      n|N ) result=1 ;;
    esac
  done

  return $result
}

用法

if @confirm 'Confirm?' ; then
  echo "Yes"
else
  echo "No"
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 ""