转：shell除法0.1，打印整数部分

 参考：https://developer.aliyun.com/article/498257

echo "scale=2; a = 5 / 6; if (length(a)==scale(a)) print 0;print a" |bc

转：shell浮点运算四舍五入

 https://www.cnblogs.com/iroultron/archive/2012/08/05/2623779.html

printf "%.3f\n" `echo ".2998"`
0.300

默认做了四舍五入

# printf "%.3f\n" `echo "scale=2;6/4" |bc`

1.500

# printf "%.0f\n" `echo "scale=2;6/4" |bc`

2

转: Linux shel浮点l除法，精确到指定小数位数

https://blog.csdn.net/naiveloafer/article/details/8783518

2) echo "scale=2;$a/$b" | bc
结果为 1.71

percent=`echo "scale=2; $total_get * 100 / $pro_num "|bc`

[popexizhi: scale= 指定位数， bc 确定浮点数计算]