CODEWITHSUNDEEP
bashshellcommand-line-arguments
Cory
Cory

Reputation: 145

Bash counting Arguments

I am having an issue counting the arguments I enter in my shell script. My script is suppose to echo "You have entered too many arguments" by using and Else statement at the end of my code. If I enter more than 3 I get nothing. Am I missing something simple or should I change this to a case statement. I am new to shell scripting so any help would be greatly appreciated. 

#!/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

Upvotes: 1

Views: 82

Answers (2)

chepner
chepner

Reputation: 531165

Your else statement is associated with the wrong if statement, but you can replace the big if-elif chain with a single case statement.

#!/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

Upvotes: 3

Renaud Pacalet
Renaud Pacalet

Reputation: 29050

Your if statements are wrongly nested. You wrote:

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

while you should have written:

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

Upvotes: 3

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