语法错误：循环变量错误(Syntax error: Bad for loop variable)

语法错误：循环变量错误(Syntax error: Bad for loop variable)

我正在尝试编写一个将在后台播放广播的脚本

#!/bin/sh for (( i = 80 ; i <= 101; i++ )) do amixer cset numid=1 i$% sleep 60; done

但我有问题：

alarmclock-vol.sh: 3: alarmclock-vol.sh: Syntax error: Bad for loop variable

I'm trying to write a script that will vol up radio in the background

#!/bin/sh for (( i = 80 ; i <= 101; i++ )) do amixer cset numid=1 i$% sleep 60; done

But i have problem:

alarmclock-vol.sh: 3: alarmclock-vol.sh: Syntax error: Bad for loop variable

最满意答案

for (( expr ; expr ; expr ))语法在sh不可用。 如果要使用该语法，请切换到bash或ksh93。 否则，sh的等价物是：

#!/bin/sh i=80 while [ "$i" -le 101 ]; do amixer cset numid=1 "$i%" sleep 60 i=$(( i + 1 )) done

The for (( expr ; expr ; expr )) syntax is not available in sh. Switch to bash or ksh93 if you want to use that syntax. Otherwise, the equivalent for sh is:

#!/bin/sh i=80 while [ "$i" -le 101 ]; do amixer cset numid=1 "$i%" sleep 60 i=$(( i + 1 )) done