Question

我想创建一个脚本，在你输入第一个命令之后，我希望被发送回上一个。

#!/bin/bash
read -p " Please enter [x ; y ; z]: " COMMAND
if [ "$COMMAND" = x ] ; then
    echo " This is command X. "
#Then return to    read -p " Please enter [x ; y ; z]: " COMMAND

elif [ "$COMMAND" = y ]; then
    echo " This is command y. "
#Then return to    read -p " Please enter [x ; y ; z]: " COMMAND

elif [ "$COMMAND" = z ]; then
    echo " This is command z"
#Then return to    read -p " Please enter [x ; y ; z]: " COMMAND

else
    echo " Command not found! "
fi

例如，如果键入x，我希望可以在y或z之后键入。它可以在同一个脚本中完成吗？

Answer 1

递归函数可以轻松完成工作

#!/bin/bash
readfun(){
read -p " Please enter [x ; y ; z]: " command  # Use lowercase names
[[ "$command" =~ ^[xyz]$ ]] && readfun 
# logical AND ie '&&' terminates the recursion if any character other than x y z is entered
}
readfun #starting point for the script
echo "Command : ${command} not found"

Answer 2

将整个事物包装在一个永无止境的while循环中：

while true
do
    [whatever]
done

Answer 3

在循环中包裹您想要重复的部分，并考虑如何从循环中退出。如果输入break，q命令将退出循环。否则，在if语句完成后，您将返回循环的顶部进行另一轮。

while true; do
    read -p " Please enter [x ; y ; z; q]: " COMMAND
    if [ "$COMMAND" = x ] ; then
        echo " This is command X. "        
    elif [ "$COMMAND" = y ]; then
        echo " This is command y. "        
    elif [ "$COMMAND" = z ]; then
        echo " This is command z"
    elif [ "$COMMAND" = q ]; then
        break
    else
        echo " Command not found! "
    fi
done

您可以使用case语句而不是大if语句来清除它。您可以为每个选项执行多个命令; ;;表示每个特定块的结束。

while true; do
    read -p " Please enter [x ; y ; z; q]: " COMMAND
    case $COMMAND in
        x) echo "This is command X."
           ;;
        y) echo "This is command Y."
           ;;
        z) echo "This is command Z."
           ;;
        q) break ;;
    esac
done

您还可以包含一个特定的测试来代替true命令，以便循环本身可以检查命令的值并终止，而不是等待显式的break命令。

while [ "$COMMAND" -ne q ]; do
    read -p " Please enter [x ; y ; z; q]: " COMMAND
    case $COMMAND in
        x) echo "This is command X."
           ;;
        y) echo "This is command Y."
           ;;
        z) echo "This is command Z."
           ;;
    esac
done

Answer 4

而且案例：＃！/斌/庆典虽然如此做读-p＆＃34;请输入[x; y; z]：＆＃34;命令 case $ COMMAND in x）回声＆＃34;这是命令x。＆＃34; ;; y）回声＆＃34;这是命令y。＆＃34; ;; z）回声＆＃34;这是命令z。＆＃34; ;; *）退出0 ;; ESAC DONE 在行动： $ bash test.sh 请输入[x; y; z]：x 这是命令x。请输入[x; y; z]：你这是命令y。请输入[x; y; Z Z 这是命令z。请输入[x; y; z]：a $

＃！/ bin / bash读取如果然后返回读取

4 个答案: