如何在if语句中使用bash脚本中的小数进行计算

Question

 #SET INITIAL SPEED
initialspeed() {

wpm=$2

#CHECKS IF SPEED WAS GIVEN
if [ -z "$wpm" ]
then
let wpm=0.6
sleep $wpm

#CHECK IF SPEED IS VALID
elif [ $wpm > 0.6 ]
then
echo Error speed is less than 100 wpm
exit 3
elif [ $wpm < 0.06 ]
then
echo Error speed is more than 1000 wpm
exit 3
else
sleep $wpm
fi
}

我试图为我的睡眠定时器设定一个速度，但我认为我遇到了问题，因为小数在let和if statements中。如何在bash脚本中使用小数？请举例说明。提前谢谢你

Answer 1

bash仅限于整数算法。

如果您有GNU (如Linux)，可以使用bc进行浮点比较，如下所示：

if echo "$wpm > 0.6" | bc -l | grep -q 1
then
    echo speed is greater than 0.6
else
    echo speed is less than or equal to 0.6
fi

对于非GNU bc，也可以使用稍微长一些的语句：

if echo "if ($wpm > 0.6) print 1 else print 0 " | bc -l | grep -q 1
then
    echo speed is greater than 0.6
else
    echo speed is less than or equal to 0.6
fi