linux之 select

wabb44400

select控制结构常用于程序选择控制，根据用户输入决定下一步的输出。

语法：

select varname [ in arg ...]
do
      comd
done

示例：

[root@hunt1574 ~]# sh test.sh
1) January
2) February
3) March
4) April
5) May
6) June
7) July
8) August
9) September
10) October
11) November
12) December
13) stop
enter your choices:1
You chose number is January.
The choice number is 1.

enter your choices:09
You chose number is September.
The choice number is 09.

enter your choices:90
Invalid entry.

enter your choices:13
Thanks!

脚本内容：

#!/bin/bash
COLUMNS=20
PS3="enter your choices:"
select input in January February March April May June July August September October November December stop
do
        if [ "$input" == "" ];then
                echo -e "Invalid entry.\n"
                continue
        elif [ $input = stop ];then
                echo "Thanks!"
                break
        fi
echo "You chose number is $input."
echo -e "The choice number is $REPLY.\n "
done

说明:

select 使用LINES和COLUMNS控制显示区域的大小，LINES默认值为24，COLUMNS默认值为80，如果不显示的指定，执行时的显示如下：

[root@hunt1574 ~]# sh test.sh
1) January      4) April       7) July       10) October    13) stop
2) February     5) May         8) August     11) November
3) March        6) June        9) September  12) December