Question

我在计算我在shell脚本中输入的参数时遇到了问题。我的脚本假设通过在代码末尾使用和Else语句来回显“你输入了太多参数”。如果我输入超过3，我什么也得不到。我是否遗漏了一些简单的内容，或者我应该将其更改为案例陈述。我是shell脚本的新手，所以任何帮助都将不胜感激。

#!/bin/bash
clear

Today=$(date +"%m-%d-%y")
echo -en '\n'
echo "To find out more about this calculator please refer to the calc.readme file."
echo -en '\n'
echo "You entered $*"
echo -en '\n'
if [ "$#" -eq "3" ]; then
if   [ "$2" == "+" ]; then
    answer=`expr $1 + $3`
    echo "You entered the correct amount of arguments"
    echo -en '\n'
    echo "Your total is: "`expr $1 + $3`
    echo "[$Today]: $@ = $answer"  >> calc.history
elif [ "$2" == "-" ]; then
    answer=`expr $1 - $3`
    echo "You entered the correct amount of arguments"
    echo -en '\n'
    echo "Your total is: "`expr $1 - $3`
    echo "[$Today]: $@ = $answer" >> calc.history
 elif [ "$2" == "*" ]; then
    answer=`expr $1 \* $3`
    echo "You entered the correct amount of arguments"
    echo -en '\n'
    echo "Your total is: "`expr $1 \* $3`
    echo "[$Today]: $@ = $answer" >> calc.history
 elif [ "$2" == "/" ]; then
    asnwer=`expr $1 / $3`
    echo "You entered the correct amount of arguments"
    echo -en '\n'
    echo "Your total is: "`expr $1 / $3`
    echo "[$Today]: $@ = $answer" >> calc.history
 else
    echo -en '\n'
    echo "You entered too many arguments."
  fi
  fi

Answer 1

您的if语句被错误地嵌套。你写道：

if <test on number of arguments>
  if <values>
  else
    <wrong number of arguments>
  fi
fi

虽然你应该写：

if <test on number of arguments>
  if <values>
  fi
else
  <wrong number of arguments>
fi

Answer 2

您的else语句与错误的if语句相关联，但您可以使用单个if-elif语句替换大case个链。

#!/bin/bash
clear

today=$(date +"%m-%d-%y")
echo
echo "To find out more about this calculator please refer to the calc.readme file."
echo
echo "You entered $*"
echo

if [ "$#" -eq "3" ]; then
  echo "You entered the correct amount of arguments"
  case $2 in
    [+-*/])
      echo
      answer=$(( $1 $2 $3 ))
      echo "Your total is $answer"
      echo "[$today]: $@ = $answer" >> calc.history
      ;;
    *) echo "Unrecognized operator $2"
       ;;
  esac
else
  echo
  echo "You entered too many arguments."
fi

Bash计算参数

2 个答案: