Bash脚本计算风寒温度时bc命令未找到问题求助

我是编程和Linux Bash新手，编写脚本计算风寒温度时遇到问题。风寒温度公式如下：

WindChill = 35.74 + (0.6215×AirTemp) - (35.75×(WindSpeed^0.16)) + (0.4275×AirTemp×(WindSpeed^0.16))

读取AirTemp和WindSpeed后，我用命令pow=$(echo "$WindSpeed^0.16" | bc)计算WindSpeed的0.16次幂，但不管用^还是**，都报错：Line 61: bc: command not found。相关脚本代码片段如下：

# get operands and start computing based on the user's choice
if [[ $choice -eq 1 ]] ; then
    echo Enter AirTemp value:
    read AirTemp
    echo Enter WindSpeed value:
    read WindSpeed
pow=$(echo "$WindSpeed^0.16" | bc)
WindChill=`echo "35.74 + (0.6215 * $AirTemp) - (35.75 * $pow) + (0.4275 * $AirTemp * $pow)"` 
#WindChill = (35.74 + (0.6215*AirTemp) - (35.75*(WindSpeed^0.16))+(0.4275*AirTemp*(WindSpeed^0.16)) =77.95  EX: Airtemp 75F, Windspeed 3mph
    echo ----------------------------------------
    echo Windchill Temp of $AirTemp and $WindSpeed in F is $WindChill
    echo ----------------------------------------
    echo

解决步骤 #

• 安装bc工具：报错bc: command not found是因为系统未安装bc计算器工具，根据你的Linux发行版执行对应安装命令：

  • Debian/Ubuntu系：sudo apt install bc
  • RHEL/CentOS系：sudo yum install bc
  • Fedora：sudo dnf install bc

• 启用bc数学库处理浮点幂运算：bc默认不支持小数次幂计算，需要加-l参数调用数学库，修改幂运算命令：

  pow=$(echo "$WindSpeed^0.16" | bc -l)
  

• 用bc计算WindChill结果：原命令直接用echo输出的是字符串，不会执行浮点计算，需同样通过bc处理：

  WindChill=$(echo "35.74 + (0.6215 * $AirTemp) - (35.75 * $pow) + (0.4275 * $AirTemp * $pow)" | bc -l)
  

• 修正脚本缩进：pow=和WindChill=两行需与if块内其他命令保持一致缩进，避免逻辑错误。

修改后的完整代码片段 #

# get operands and start computing based on the user's choice
if [[ $choice -eq 1 ]] ; then
    echo Enter AirTemp value:
    read AirTemp
    echo Enter WindSpeed value:
    read WindSpeed
    pow=$(echo "$WindSpeed^0.16" | bc -l)
    WindChill=$(echo "35.74 + (0.6215 * $AirTemp) - (35.75 * $pow) + (0.4275 * $AirTemp * $pow)" | bc -l)
    # 示例：AirTemp=75F，WindSpeed=3mph时，结果应为77.95左右
    echo ----------------------------------------
    echo Windchill Temp of $AirTemp and $WindSpeed in F is $WindChill
    echo ----------------------------------------
    echo
fi

内容的提问来源于stack exchange，提问作者Matthew Watson