Bash Shell 脚本：嵌套选择语句答案

【问题标题】：Bash Shell Script: Nested Select StatementsBash Shell 脚本：嵌套选择语句
【发布时间】：2010-04-08 00:29:27
【问题描述】：

我有一个脚本，它有一个 Select 语句可以转到多个子 select 语句，但是一旦出现，我似乎无法弄清楚如何让它返回到主脚本。如果可能的话，我希望它重新列出选项

  #!/bin/bash
           PS3='Option = '
           MAINOPTIONS="Apache Postfix Dovecot All Quit"
           APACHEOPTIONS="Restart Start Stop Status"
           POSTFIXOPTIONS="Restart Start Stop Status"
           DOVECOTOPTIONS="Restart Start Stop Status"
           select opt in $MAINOPTIONS; do
               if [ "$opt" = "Quit" ]; then
               echo Now Exiting
               exit
               elif [ "$opt" = "Apache" ]; then
                 select opt in $APACHEOPTIONS; do
                 if [ "$opt" = "Restart" ]; then
                 sudo /etc/init.d/apache2 restart
                 elif [ "$opt" = "Start" ]; then
                 sudo /etc/init.d/apache2 start
                 elif [ "$opt" = "Stop" ]; then
                 sudo /etc/init.d/apache2 stop
                 elif [ "$opt" = "Status" ]; then
                 sudo /etc/init.d/apache2 status
                 fi
                 done
               elif [ "$opt" = "Postfix" ]; then
                 select opt in $POSTFIXOPTIONS; do
                 if [ "$opt" = "Restart" ]; then
                 sudo /etc/init.d/postfix restart
                 elif [ "$opt" = "Start" ]; then
                 sudo /etc/init.d/postfix start
                 elif [ "$opt" = "Stop" ]; then
                 sudo /etc/init.d/postfix stop
                 elif [ "$opt" = "Status" ]; then
                 sudo /etc/init.d/postfix status
                 fi
                 done
               elif [ "$opt" = "Dovecot" ]; then
                 select opt in $DOVECOTOPTIONS; do
                 if [ "$opt" = "Restart" ]; then
                 sudo /etc/init.d/dovecot restart
                 elif [ "$opt" = "Start" ]; then
                 sudo /etc/init.d/dovecot start
                 elif [ "$opt" = "Stop" ]; then
                 sudo /etc/init.d/dovecot stop
                 elif [ "$opt" = "Status" ]; then
                 sudo /etc/init.d/dovecot status
                 fi
                 done
                 elif [ "$opt" = "All" ]; then
                 sudo /etc/init.d/apache2 restart
                 sudo /etc/init.d/postfix restart
                 sudo /etc/init.d/dovecot restart
               fi
               done

【问题讨论】：

标签： bash shell select

【解决方案1】：

您通常会将case 语句嵌套在select 语句中，并将整个内容置于一个循环中：

while true
do
    select option in $options
    do
        case $option in
            choice1)
                do_something
                ;;
            choice2)
                select sub_option in $sub_options
                do
                    case $sub_option in
                        sub_choice1)
                            another_thing
                            ;;
                        sub_choice2)
                            break    # return to current (sub) menu
                            ;;
                        sub_choice3)
                            break 2  # return to parent menu
                            ;;
                     esac
            choice3)
                 break    # return to current (main) menu
                 ;;
            choice4)
                 break 2  # exit the while loop so cleanup can be done at the end of the script
        esac
    done
done
do_cleanup

【讨论】：

【解决方案2】：

您使用循环来执行此操作..

while true
do
...
...
  read -p "do you want to continue (Q)uit?" choice
  case "$choice" in
    Q|q) break;; #or exit your script
  esac
...
done

【讨论】：

【解决方案3】：

bourne shell 有一个有用的结构，我有时希望 C 有。

您可以使用“break n”打破嵌套的控制结构，其中 n 可以是 2、3 等。

因此，从您的嵌套子选择中，您可以发出 break 2; 以返回顶层。不过，我并不完全肯定您要实现的目标。

【讨论】：