使用（不在）bash 的 while 循环
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/25527564/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
While loop using (not in) bash
提问by Odin
I am trying to have while check the value of an input variable. For example while will only exist if value of option is 1 or 2.
我正在尝试检查输入变量的值。For example while will only exist if value of option is 1 or 2.
while option not in 1 2
do :
read -p "Please choose an option" option
done
How this can be done in bash?
这如何在 bash 中完成？
[Duplicate] This is not a duplicate because the one marked as duplicate such consider comparing two strings without having multiple options at one end.
[重复] 这不是重复的，因为标记为重复的那个考虑比较两个字符串，而在一端没有多个选项。
回答by William Pursell
The classical way is:
经典的方法是：
while ! { test "$option" = 1 || test "$option" = 2; }; do ...
while ! { test "$option" = 1 || test "$option" = 2; }; do ...
but a cleaner way is to use a case statement:
但更简洁的方法是使用 case 语句：
while :; do
case "$option" in
1|2) break ;;
*) ... ;;
esac
done
回答by Lorenzo Marcon
I'd do something like that:
我会做这样的事情：
#!/bin/bash
while : ; do
echo "Please choose an option"
read val
[[ $val != 1 && $val != 2 ]] || break
done
回答by Adrian Frühwirth
Use the selectbuiltin:
使用select内置：
$ cat select.sh
#!/bin/bash
options=("Option 1" "Option 2")
echo "Please choose an option:"
select option in "${options[@]}"; do
[ -n "${option}" ] && break
done
echo "You picked: ${option}"
?
?
$ ./select.sh
Please choose an option:
1) Option 1
2) Option 2
#? 3
#? xyz
#? 2
You picked: Option 2
回答by chepner
In bash, you can use pattern matching to test $option:
在 中bash，您可以使用模式匹配来测试$option：
while [[ $option != [12] ]]; do
read -p "Please choose an option: " option
done
回答by Cajus Pollmeier
Or if you plan to evaluate more options, use case:
或者，如果您打算评估更多选项，请使用案例：
#!/bin/bash
while true; do
read -p "Please choose an option" option
case "$option" in
[12]) break
;;
*) echo "whatever"
esac
done
回答by anubhava
You can use this whilecondition using {...}list construct and shell globbing:
您可以使用列表构造和使用此while条件：{...}shell globbing
option=0
while [[ $(echo {1,2}) != *"$option"* ]]; do
read -p "Please choose an option: " option
done
回答by anubhava
I think this is the most common way
我认为这是最常见的方式
while [[ "$option" -ne 1 ]] || [[ "$option" -ne 2 ]]; do
read -p "Please choose an option" option
done
