Fibonacci Series Using Bash Script

This simple program help you to logically put and modify the vars as per the requirement, helping you to understand the fibonacci series

#!/bin/bash
# First Number of the Fibonacci Series
a=0

# Second Number of the Fibonacci Series
b=1

# Number of terms to generate (provided as a command-line argument)
N=$1

# Check if input is valid
if [[ -z "$N" || "$N" -le 0 ]]; then
  echo "Please provide a positive integer as input."
  exit 1
fi

# Initialize the sum variable
sum=0

echo "The Fibonacci series is:"

for ((i = 0; i < N; i++)); do
  echo -n "$a "
  
  # Add the current term to the sum
  sum=$((sum + a))
  
  # Calculate the next Fibonacci number
  fn=$((a + b))
  a=$b
  b=$fn
done

echo
echo "The sum of the Fibonacci series is: $sum"

O/P

Flow:
Initialization

• The script begins by initializing the first two terms of the Fibonacci series:
• a=0: The first term.
• b=1: The second term.
• The user provides the number of terms (N) as a command-line argument ($1).

Loop Through N Terms

• A for loop runs from 0 to N-1 (inclusive):
• Print the Current Term: The value of a is printed, representing the current Fibonacci term.
• Calculate the Next Term:
• Compute the next term: fn = a + b.
• Update a to hold the value of b (shift one position forward).
• Update b to hold the value of fn (next term).
• The loop ensures all terms are generated iteratively without recursion.

Calculate the Sum

• During the loop, each term (a) is added to the variable sum to keep track of the total.
• Once the loop finishes, the sum of all Fibonacci numbers is displayed