如何在Linux shell脚本中提示是/否/取消输入？

我想在shell脚本中暂停输入,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？

在shell提示符下获取用户输入的最简单且最广泛可用的方法是read命令.说明其用法的最佳方式是一个简单的演示:

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.以下是使用相同的示例select:

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

随着select你并不需要净化输入-它显示可用的选项,你键入相应的你的选择一个号码.它也会自动循环,因此while true如果它们提供无效输入,则无需重试循环.

另外,请查看F. Hauri 的优秀答案.

取决于

符合posix:可以在具有通用shell环境的不良系统上工作

bash具体:使用所谓的bashisms

如果你想要的话

简单的``在线''问题/答案(通用解决方案)

相当格式化的接口,如使用libgtk或libqt的ncurses或更多图形...

使用强大的readline历史记录功能

1. POSIX通用解决方案

您可以使用该read命令,然后执行以下操作if ... then ... else:

echo -n "Is this a good question (y/n)? "
read answer

# if echo "$answer" | grep -iq "^y" ;then

if [ "$answer" != "${answer#[Yy]}" ] ;then
    echo Yes
else
    echo No
fi

(感谢Adam Katz的评论:将上面的测试替换为一个更便携的测试并避免使用一个分叉:)

POSIX,但是单一的关键功能

但如果您不希望用户必须点击Return,您可以写:

(编辑:正如@JonathanLeffler正确地建议的那样,保存 stty的配置可能比仅仅强迫他们理智更好.)

echo -n "Is this a good question (y/n)? "
old_stty_cfg=$(stty -g)
stty raw -echo ; answer=$(head -c 1) ; stty $old_stty_cfg # Careful playing with stty
if echo "$answer" | grep -iq "^y" ;then
    echo Yes
else
    echo No
fi

注意:这是在sh,bash,ksh,dash和busybox下测试的!

相同,但明确等待y或n:

#/bin/sh
echo -n "Is this a good question (y/n)? "
old_stty_cfg=$(stty -g)
stty raw -echo
answer=$( while ! head -c 1 | grep -i '[ny]' ;do true ;done )
stty $old_stty_cfg
if echo "$answer" | grep -iq "^y" ;then
    echo Yes
else
    echo No
fi

使用专用工具

有很多其使用内置的工具libncurses,libgtk,libqt或其他图形库.例如,使用whiptail:

if whiptail --yesno "Is this a good question" 20 60 ;then
    echo Yes
else
    echo No
fi

根据您的系统,您可能需要更换whiptail另一个类似的工具:

dialog --yesno "Is this a good question" 20 60 && echo Yes

gdialog --yesno "Is this a good question" 20 60 && echo Yes

kdialog --yesno "Is this a good question" 20 60 && echo Yes

20对话框的高度在哪里,行数60是对话框的宽度.这些工具都具有几乎相同的语法.

DIALOG=whiptail
if [ -x /usr/bin/gdialog ] ;then DIALOG=gdialog ; fi
if [ -x /usr/bin/xdialog ] ;then DIALOG=xdialog ; fi
...
$DIALOG --yesno ...

2. Bash特定解决方案

基本的在线方法

read -p "Is this a good question (y/n)? " answer
case ${answer:0:1} in
    y|Y )
        echo Yes
    ;;
    * )
        echo No
    ;;
esac

我更喜欢使用,case所以yes | ja | si | oui如果需要我甚至可以测试......

本着与单键功能

在bash下,我们可以为read命令指定预期输入的长度:

read -n 1 -p "Is this a good question (y/n)? " answer

在bash下,read命令接受超时参数,这可能很有用.

read -t 3 -n 1 -p "Is this a good question (y/n)? " answer
[ -z "$answer" ] && answer="Yes"  # if 'yes' have to be default choice

专用工具的一些技巧

除了简单的yes - no目的之外,更复杂的对话框:

dialog --menu "Is this a good question" 20 60 12 y Yes n No m Maybe

进度条:

dialog --gauge "Filling the tank" 20 60 0 < <(
    for i in {1..100};do
        printf "XXX\n%d\n%(%a %b %T)T progress: %d\nXXX\n" $i -1 $i
        sleep .033
    done
) 

小演示:

#!/bin/sh
while true ;do
    [ -x "$(which ${DIALOG%% *})" ] || DIALOG=dialog
    DIALOG=$($DIALOG --menu "Which tool for next run?" 20 60 12 2>&1 \
            whiptail       "dialog boxes from shell scripts" >/dev/tty \
            dialog         "dialog boxes from shell with ncurses" \
            gdialog        "dialog boxes from shell with Gtk" \
            kdialog        "dialog boxes from shell with Kde" ) || exit
    clear;echo "Choosed: $DIALOG."
    for i in `seq 1 100`;do
        date +"`printf "XXX\n%d\n%%a %%b %%T progress: %d\nXXX\n" $i $i`"
        sleep .0125
      done | $DIALOG --gauge "Filling the tank" 20 60 0
    $DIALOG --infobox "This is a simple info box\n\nNo action required" 20 60
    sleep 3
    if $DIALOG --yesno  "Do you like this demo?" 20 60 ;then
        AnsYesNo=Yes; else AnsYesNo=No; fi
    AnsInput=$($DIALOG --inputbox "A text:" 20 60 "Text here..." 2>&1 >/dev/tty)
    AnsPass=$($DIALOG --passwordbox "A secret:" 20 60 "First..." 2>&1 >/dev/tty)
    $DIALOG --textbox /etc/motd 20 60
    AnsCkLst=$($DIALOG --checklist "Check some..." 20 60 12 \
        Correct "This demo is useful"        off \
        Fun        "This demo is nice"        off \
        Strong        "This demo is complex"        on 2>&1 >/dev/tty)
    AnsRadio=$($DIALOG --radiolist "I will:" 20 60 12 \
        " -1" "Downgrade this answer"        off \
        "  0" "Not do anything"                on \
        " +1" "Upgrade this anser"        off 2>&1 >/dev/tty)
    out="Your answers:\nLike: $AnsYesNo\nInput: $AnsInput\nSecret: $AnsPass"
    $DIALOG --msgbox "$out\nAttribs: $AnsCkLst\nNote: $AnsRadio" 20 60
  done

更多样品？看看使用whiptail选择USB设备和USB可移动存储选择器:USBKeyChooser

5.使用readline的历史记录

例:

#!/bin/bash

set -i
HISTFILE=~/.myscript.history
history -c
history -r

myread() {
    read -e -p '> ' $1
    history -s ${!1}
}
trap 'history -a;exit' 0 1 2 3 6

while myread line;do
    case ${line%% *} in
        exit )  break ;;
        *    )  echo "Doing something with '$line'" ;;
      esac
  done

这将创建一个文件.myscript.history在$HOME目录中,比你能使用输入行的历史命令,比如Up, Down,Ctrl+ r等.

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

您可以使用内置的read命令; 使用该-p选项可向用户提示问题.

从BASH4开始,您现在可以使用-i建议答案,因此用户只需按下-e即可输入:

read -e -p "Enter the path to the file: " -i "/usr/local/etc/" FILEPATH
echo $FILEPATH

(但请记住使用"readline"选项-p允许使用箭头键进行行编辑)

如果你想要一个"是/否"逻辑,你可以这样做:

read -e -p "
List the content of your home dir ? [Y/n] " YN

[[ $YN == "y" || $YN == "Y" || $YN == "" ]] && ls -la ~/

Bash已经选择了这个目的.

select result in Yes No Cancel
do
    echo $result
done

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

这是我放在一起的东西:

#!/bin/sh

promptyn () {
    while true; do
        read -p "$1 " yn
        case $yn in
            [Yy]* ) return 0;;
            [Nn]* ) return 1;;
            * ) echo "Please answer yes or no.";;
        esac
    done
}

if promptyn "is the sky blue?"; then
    echo "yes"
else
    echo "no"
fi

我是一个初学者,所以带上一粒盐,但似乎有效.

inquire ()  {
  echo  -n "$1 [y/n]? "
  read answer
  finish="-1"
  while [ "$finish" = '-1' ]
  do
    finish="1"
    if [ "$answer" = '' ];
    then
      answer=""
    else
      case $answer in
        y | Y | yes | YES ) answer="y";;
        n | N | no | NO ) answer="n";;
        *) finish="-1";
           echo -n 'Invalid response -- please reenter:';
           read answer;;
       esac
    fi
  done
}

... other stuff

inquire "Install now?"

...

你要:

Bash内置命令(即便携式)

检查TTY

默认答案

超时

有色的问题

片段

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

说明

[[ -t 0 ]] && read ...=> read如果TTY,则调用命令

read -n 1 =>等一个字符

$'\e[1;32m ... \e[0m '=>以绿色打印
(绿色很好,因为白色/黑色背景都可读)

[[ $do_xxxx =~ ^(y|Y|)$ ]] => 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

使用最少行数实现此目的的最简单方法如下:

read -p " : y/n/cancel" CONDITION;

if [ "$CONDITION" == "y" ]; then
   # do something here!
fi

这if只是一个例子:由你决定如何处理这个变量.

使用read命令:

echo Would you like to install? "(Y or N)"

read x

# now check if $x is "y"
if [ "$x" = "y" ]; then
    # do something here!
fi

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

read -e -p "Enter your choice: " choice

read -e -i "yes" -p "Enter your choice: " choice

read -rp "Do you want a demo? [y/n/c] "

[[ ${REPLY,,} =~ ^(c|cancel)$ ]] && { echo "Selected Cancel"; exit 1; }

if [[ ${REPLY,,} =~ ^(y|yes|j|ja|s|si|o|oui)$ ]]; then
   echo "Positive"
fi

echo -n "These files will be uploaded. Is this ok? (y/n) "
read yesno < /dev/tty

if [ "x$yesno" = "xy" ];then

   # Yes
else

   # No
fi

#!/bin/bash
if (dialog --title "Message" --yesno "Want to do something risky?" 6 25)
# message box will have the size 25x6 characters
then 
    echo "Let's do something risky"
    # do something risky
else 
    echo "Let's stay boring"
fi

$ confirm "Show dangerous command" && echo "rm *"
Show dangerous command [y/N]?

$ confirm "Show dangerous command" && echo "rm *"
Show dangerous command [y/N]? X
Show dangerous command [y/N]? y
rm *

$ confirm_yes "Show dangerous command" && echo "rm *"
Show dangerous command [Y/n]?
rm *

$ get_yes_keypress "Here you cannot press enter. Do you like this [y/n]? "
Here you cannot press enter. Do you like this [y/n]? k
Here you cannot press enter. Do you like this [y/n]?
Here you cannot press enter. Do you like this [y/n]? n
$ echo $?
1

# Read a single char from /dev/tty, prompting with "$*"
# Note: pressing enter will return a null string. Perhaps a version terminated with X and then remove it in caller?
# See https://unix.stackexchange.com/a/367880/143394 for dealing with multi-byte, etc.
function get_keypress {
  local REPLY IFS=
  >/dev/tty printf '%s' "$*"
  [[ $ZSH_VERSION ]] && read -rk1  # Use -u0 to read from STDIN
  # See https://unix.stackexchange.com/q/383197/143394 regarding '\n' -> ''
  [[ $BASH_VERSION ]] && 
# Usage: confirm "Dangerous. Are you sure?" && rm *
function confirm {
  local prompt="${*:-Are you sure} [y/N]? "
  get_yes_keypress "$prompt" 1
}    

# Prompt to confirm, defaulting to YES on 
function confirm_yes {
  local prompt="${*:-Are you sure} [Y/n]? "
  get_yes_keypress "$prompt" 0
}

#!/bin/bash

function ask_user() {    

echo -e "
#~~~~~~~~~~~~#
| 1.) Yes    |
| 2.) No     |
| 3.) Quit   |
#~~~~~~~~~~~~#\n"

read -e -p "Select 1: " choice

if [ "$choice" == "1" ]; then

    do_something

elif [ "$choice" == "2" ]; then

    do_something_else

elif [ "$choice" == "3" ]; then

    clear && exit 0

else

    echo "Please select 1, 2, or 3." && sleep 3
    clear && ask_user

fi
}

ask_user