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