CODEWITHSUNDEEP
bashfunctionloopsbreak
David Peltier
David Peltier

Reputation: 91

Looping function bash

I'm currently learning bash and I'm working on loop function to recall the function if the value is not the expected.

I create a small function

#!/bin/bash

find_number(){
  echo "Enter number"
  read number

  if [ ! $number == 1 ]; then
    echo is not 1, enter number again
    find_number
  fi

echo "Got it"
}

find_number

If you enter a bad value it restart the function and create a loop but the only problem is that the functions loops itself and finally when it continues it returns the echo as many time as you got it wrong.

Exemple:

   Enter number
   5
   is not 1, enter number again
   Enter number
   5
   is not 1, enter number again
   Enter number
   1
   Got it
   Got it
   Got it

As you see here I've got the result 3 times. To resolve this problem I've writtten my code in another way.

#!/bin/bash

find_number(){

  echo "Enter number"

  while read number; do
    if [ ! $number == 1 ]; then
      echo is not 1, enter number again
    else
      break
    fi
  done

echo "Got it"
}

find_number

My question is...am I doing it the right way by applying this second method or there's another way of doing it ?

thanks for your feedback

Upvotes: 1

Views: 66

Answers (2)

Vadim Beskrovnov
Vadim Beskrovnov

Reputation: 961

You are using recursion, not loop. Try to use loop in this way:

#!/bin/bash

find_number(){
  echo "Enter number"
  read number

  while [ ! "${number}" == "1" ]; do
    echo "is not 1, enter number again"
    read number
  done

  echo "Got it"
}

find_number

Upvotes: 0

Sunny Patel
Sunny Patel

Reputation: 8078

Since you are using recursion to 'loop', when each function finishes, you are still performing the final lines of that function as they complete.

To truly create a loop, you would use your while; do structure to perform it properly.

Calling the function itself for recursion can create a bigger overhead if you don't have a solid base (ending) condition.

Upvotes: 1

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