### 在bash中进行小数比较
#### 1 `bc`
```bash
if [ `echo "3.4 < 4.5" | bc` -eq 1 ];then
    echo yes
else
    echo no
fi
```
or
```
if [ bc <<< `echo "3.4 < 4.5" ` -eq 1 ];then
    echo yes
else
    echo no
fi
```
#### 2 {} 分别比较整数和小数部分
```bash
a=1.9
b=2.3
if (( ${a%%.*} < ${b%%.*} || ${a%%.*} == ${b%%.*}  && ${a##*.} < ${b##*.} )) ;then
    echo yes
else
    echo no
fi
```