Odtnhj

I am learning Shell scripting on own. I am trying to do an assignment to get details from the user like username their individual marks ,DOB and send a report in mail with the Details calculated like total and average.

 validate_marks() 
 local Value=$1
 if [ "$Value" -ge "0" ] && [ "$Value" -le "100" ]
 then
 return 0
 else
 echo "Enter numbers between 0-100"
 exit 1.
 fi

 
 echo "Enter Marks for each subject:"
 read -p "Enter English Marks:" ENG
 validate_marks $ENG
 read -p "Enter Maths Marks:" MATHS
 validate_marks $MATHS
 read -p "Enter Science Marks:" SCI
 validate_marks $SCI
 read -p "Enter History Marks:" HIST
 validate_marks $HIST
 read -p "Enter your Email id:" EMAIL
 validate_email $EMAIL

In the validate marks function I am checking if the value entered is between 0 -100 if it is more return error and go back to prompt until it is correct. How do I achieve this.

How about modifying the function to return the validated score. Then you can enclose the looping until the valid number is given within the function.

Then the code will look like:

#!/bin/bash

function validate_marks() 
 local subject=$1
 local score
 while true; do
 read -p "Enter $subject:" score
 if [[ "$score" =~ ^[0-9]+$ ]] && [[ "$score" -ge 0 ]] && [[ "$score" -le 100 ]]; then
 echo "$score"
 return
 else
 echo "** Enter numbers between 0-100 **" >&2
 fi
 done


echo "Enter Marks for each subject:"

ENG=$(validate_marks "English Marks")
MATHS=$(validate_marks "Maths Marks")
SCI=$(validate_marks "Science Marks")
HIST=$(validate_marks "History Marks")
EMAIL=$(validate_marks "your Email id")

• 
  while true creates an infinite loop to keep on asking for an input until the if condition is met.


• The "$score" =~ ^[0-9]+$ portion checks if the user input is a number just to avoid an internal error.


• The output of the bash function is transmitted to the caller via stdout with echo or something like that.


• Then the message within the function should be sent to stderr by >&2.

Hope this helps.