方向键/进入菜单

Question 1

这是函数bash形式的纯脚本解决方案select_option，仅依赖于ANSI 转义序列和内置的read.

适用于 OSX 上的 Bash 4.2.45。据我所知，在所有环境中可能无法同样有效地工作的时髦部分是get_cursor_row(), key_input()（用于检测向上/向下键）和cursor_to()功能。

#!/usr/bin/env bash

# Renders a text based list of options that can be selected by the
# user using up, down and enter keys and returns the chosen option.
#
#   Arguments   : list of options, maximum of 256
#                 "opt1" "opt2" ...
#   Return value: selected index (0 for opt1, 1 for opt2 ...)
function select_option {

    # little helpers for terminal print control and key input
    ESC=$( printf "\033")
    cursor_blink_on()  { printf "$ESC[?25h"; }
    cursor_blink_off() { printf "$ESC[?25l"; }
    cursor_to()        { printf "$ESC[$1;${2:-1}H"; }
    print_option()     { printf "   $1 "; }
    print_selected()   { printf "  $ESC[7m $1 $ESC[27m"; }
    get_cursor_row()   { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }
    key_input()        { read -s -n3 key 2>/dev/null >&2
                         if [[ $key = $ESC[A ]]; then echo up;    fi
                         if [[ $key = $ESC[B ]]; then echo down;  fi
                         if [[ $key = ""     ]]; then echo enter; fi; }

    # initially print empty new lines (scroll down if at bottom of screen)
    for opt; do printf "\n"; done

    # determine current screen position for overwriting the options
    local lastrow=`get_cursor_row`
    local startrow=$(($lastrow - $#))

    # ensure cursor and input echoing back on upon a ctrl+c during read -s
    trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
    cursor_blink_off

    local selected=0
    while true; do
        # print options by overwriting the last lines
        local idx=0
        for opt; do
            cursor_to $(($startrow + $idx))
            if [ $idx -eq $selected ]; then
                print_selected "$opt"
            else
                print_option "$opt"
            fi
            ((idx++))
        done

        # user key control
        case `key_input` in
            enter) break;;
            up)    ((selected--));
                   if [ $selected -lt 0 ]; then selected=$(($# - 1)); fi;;
            down)  ((selected++));
                   if [ $selected -ge $# ]; then selected=0; fi;;
        esac
    done

    # cursor position back to normal
    cursor_to $lastrow
    printf "\n"
    cursor_blink_on

    return $selected
}

这是一个用法示例：

echo "Select one option using up/down keys and enter to confirm:"
echo

options=("one" "two" "three")

select_option "${options[@]}"
choice=$?

echo "Choosen index = $choice"
echo "        value = ${options[$choice]}"

输出如下所示，其中使用反 ansi 着色突出显示当前选定的选项（此处很难在 Markdown 中传达）。如果需要，可以在print_selected()函数中对此进行调整。

Select one option using up/down keys and enter to confirm:

  [one] 
   two 
   three

更新：select_opt这是一个包装上述函数的小扩展，select_option以便于在语句中使用它case：

function select_opt {
    select_option "$@" 1>&2
    local result=$?
    echo $result
    return $result
}

具有 3 个文字选项的用法示例：

case `select_opt "Yes" "No" "Cancel"` in
    0) echo "selected Yes";;
    1) echo "selected No";;
    2) echo "selected Cancel";;
esac

如果存在一些已知条目（本例中是和否），您还可以混合使用，并利用$?通配符情况的退出代码：

options=("Yes" "No" "${array[@]}") # join arrays to add some variable array
case `select_opt "${options[@]}"` in
    0) echo "selected Yes";;
    1) echo "selected No";;
    *) echo "selected ${options[$?]}";;
esac

Answer

这是函数bash形式的纯脚本解决方案select_option，仅依赖于ANSI 转义序列和内置的read.

适用于 OSX 上的 Bash 4.2.45。据我所知，在所有环境中可能无法同样有效地工作的时髦部分是get_cursor_row(), key_input()（用于检测向上/向下键）和cursor_to()功能。

#!/usr/bin/env bash

# Renders a text based list of options that can be selected by the
# user using up, down and enter keys and returns the chosen option.
#
#   Arguments   : list of options, maximum of 256
#                 "opt1" "opt2" ...
#   Return value: selected index (0 for opt1, 1 for opt2 ...)
function select_option {

    # little helpers for terminal print control and key input
    ESC=$( printf "\033")
    cursor_blink_on()  { printf "$ESC[?25h"; }
    cursor_blink_off() { printf "$ESC[?25l"; }
    cursor_to()        { printf "$ESC[$1;${2:-1}H"; }
    print_option()     { printf "   $1 "; }
    print_selected()   { printf "  $ESC[7m $1 $ESC[27m"; }
    get_cursor_row()   { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }
    key_input()        { read -s -n3 key 2>/dev/null >&2
                         if [[ $key = $ESC[A ]]; then echo up;    fi
                         if [[ $key = $ESC[B ]]; then echo down;  fi
                         if [[ $key = ""     ]]; then echo enter; fi; }

    # initially print empty new lines (scroll down if at bottom of screen)
    for opt; do printf "\n"; done

    # determine current screen position for overwriting the options
    local lastrow=`get_cursor_row`
    local startrow=$(($lastrow - $#))

    # ensure cursor and input echoing back on upon a ctrl+c during read -s
    trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
    cursor_blink_off

    local selected=0
    while true; do
        # print options by overwriting the last lines
        local idx=0
        for opt; do
            cursor_to $(($startrow + $idx))
            if [ $idx -eq $selected ]; then
                print_selected "$opt"
            else
                print_option "$opt"
            fi
            ((idx++))
        done

        # user key control
        case `key_input` in
            enter) break;;
            up)    ((selected--));
                   if [ $selected -lt 0 ]; then selected=$(($# - 1)); fi;;
            down)  ((selected++));
                   if [ $selected -ge $# ]; then selected=0; fi;;
        esac
    done

    # cursor position back to normal
    cursor_to $lastrow
    printf "\n"
    cursor_blink_on

    return $selected
}

这是一个用法示例：

echo "Select one option using up/down keys and enter to confirm:"
echo

options=("one" "two" "three")

select_option "${options[@]}"
choice=$?

echo "Choosen index = $choice"
echo "        value = ${options[$choice]}"

输出如下所示，其中使用反 ansi 着色突出显示当前选定的选项（此处很难在 Markdown 中传达）。如果需要，可以在print_selected()函数中对此进行调整。

Select one option using up/down keys and enter to confirm:

  [one] 
   two 
   three

更新：select_opt这是一个包装上述函数的小扩展，select_option以便于在语句中使用它case：

function select_opt {
    select_option "$@" 1>&2
    local result=$?
    echo $result
    return $result
}

具有 3 个文字选项的用法示例：

case `select_opt "Yes" "No" "Cancel"` in
    0) echo "selected Yes";;
    1) echo "selected No";;
    2) echo "selected Cancel";;
esac

如果存在一些已知条目（本例中是和否），您还可以混合使用，并利用$?通配符情况的退出代码：

options=("Yes" "No" "${array[@]}") # join arrays to add some variable array
case `select_opt "${options[@]}"` in
    0) echo "selected Yes";;
    1) echo "selected No";;
    *) echo "selected ${options[$?]}";;
esac

Question 2

对话是实现您想要实现的目标的绝佳工具。下面是一个简单的三项选择菜单的示例：

dialog --menu "Choose one:" 10 30 3 \
    1 Red \
    2 Green \
    3 Blue

语法如下：

dialog --menu <text> <height> <width> <menu-height> [<tag><item>]

选择将被发送至stderr。这是使用 3 种颜色的示例脚本。

#!/bin/bash
TMPFILE=$(mktemp)

dialog --menu "Choose one:" 10 30 3 \
    1 Red \
    2 Green \
    3 Blue 2>$TMPFILE

RESULT=$(cat $TMPFILE)

case $RESULT in
    1) echo "Red";;
    2) echo "Green";;
    3) echo "Blue";;
    *) echo "Unknown color";;
esac

rm $TMPFILE

在 Debian 上，您可以dialog通过以下方式安装同名包。

Answer

对话是实现您想要实现的目标的绝佳工具。下面是一个简单的三项选择菜单的示例：

dialog --menu "Choose one:" 10 30 3 \
    1 Red \
    2 Green \
    3 Blue

语法如下：

dialog --menu <text> <height> <width> <menu-height> [<tag><item>]

选择将被发送至stderr。这是使用 3 种颜色的示例脚本。

#!/bin/bash
TMPFILE=$(mktemp)

dialog --menu "Choose one:" 10 30 3 \
    1 Red \
    2 Green \
    3 Blue 2>$TMPFILE

RESULT=$(cat $TMPFILE)

case $RESULT in
    1) echo "Red";;
    2) echo "Green";;
    3) echo "Blue";;
    *) echo "Unknown color";;
esac

rm $TMPFILE

在 Debian 上，您可以dialog通过以下方式安装同名包。

Question 3

问题仅涉及一项选择。
如果您正在寻找多选菜单，这里有纯bash其实施：

使用
j/k或↑/↓箭头键向上或向下导航
⎵（空格）以切换选择，并
⏎使用 (Enter) 确认选择。

可以这样调用：

my_options=(   "Option 1"  "Option 2"  "Option 3" )
preselection=( "true"      "true"      "false"    )

multiselect result my_options preselection

该函数的最后一个参数multiselect是可选的，可用于预先选择某些选项。

结果将作为数组存储在作为第一个参数传递的变量中multiselect。下面是将选项与结果结合起来的示例：

idx=0
for option in "${my_options[@]}"; do
    echo -e "$option\t=> ${result[idx]}"
    ((idx++))
done

function multiselect {
    # little helpers for terminal print control and key input
    ESC=$( printf "\033")
    cursor_blink_on()   { printf "$ESC[?25h"; }
    cursor_blink_off()  { printf "$ESC[?25l"; }
    cursor_to()         { printf "$ESC[$1;${2:-1}H"; }
    print_inactive()    { printf "$2   $1 "; }
    print_active()      { printf "$2  $ESC[7m $1 $ESC[27m"; }
    get_cursor_row()    { IFS=';' read -sdR -p $'\E[6n' ROW COL; echo ${ROW#*[}; }

    local return_value=$1
    local -n options=$2
    local -n defaults=$3

    local selected=()
    for ((i=0; i<${#options[@]}; i++)); do
        if [[ ${defaults[i]} = "true" ]]; then
            selected+=("true")
        else
            selected+=("false")
        fi
        printf "\n"
    done

    # determine current screen position for overwriting the options
    local lastrow=`get_cursor_row`
    local startrow=$(($lastrow - ${#options[@]}))

    # ensure cursor and input echoing back on upon a ctrl+c during read -s
    trap "cursor_blink_on; stty echo; printf '\n'; exit" 2
    cursor_blink_off

    key_input() {
        local key
        IFS= read -rsn1 key 2>/dev/null >&2
        if [[ $key = ""      ]]; then echo enter; fi;
        if [[ $key = $'\x20' ]]; then echo space; fi;
        if [[ $key = "k" ]]; then echo up; fi;
        if [[ $key = "j" ]]; then echo down; fi;
        if [[ $key = $'\x1b' ]]; then
            read -rsn2 key
            if [[ $key = [A || $key = k ]]; then echo up;    fi;
            if [[ $key = [B || $key = j ]]; then echo down;  fi;
        fi 
    }

    toggle_option() {
        local option=$1
        if [[ ${selected[option]} == true ]]; then
            selected[option]=false
        else
            selected[option]=true
        fi
    }

    print_options() {
        # print options by overwriting the last lines
        local idx=0
        for option in "${options[@]}"; do
            local prefix="[ ]"
            if [[ ${selected[idx]} == true ]]; then
              prefix="[\e[38;5;46m✔\e[0m]"
            fi

            cursor_to $(($startrow + $idx))
            if [ $idx -eq $1 ]; then
                print_active "$option" "$prefix"
            else
                print_inactive "$option" "$prefix"
            fi
            ((idx++))
        done
    }

    local active=0
    while true; do
        print_options $active

        # user key control
        case `key_input` in
            space)  toggle_option $active;;
            enter)  print_options -1; break;;
            up)     ((active--));
                    if [ $active -lt 0 ]; then active=$((${#options[@]} - 1)); fi;;
            down)   ((active++));
                    if [ $active -ge ${#options[@]} ]; then active=0; fi;;
        esac
    done

    # cursor position back to normal
    cursor_to $lastrow
    printf "\n"
    cursor_blink_on

    eval $return_value='("${selected[@]}")'
}

信用：这个bash函数是一个定制版本Denis Semenenko 的实施。

Answer