🧠 100 Logical Bash Programming Questions with Descriptions

ID	Question	File Name	Description	Sample Input	Sample Output
001	Check if a number is even or odd	even_odd.sh	Take a number as input and determine if it is even or odd using modulo.	7	Odd
002	Find the largest of three numbers	largest_three.sh	Compare three numbers using if-else to find the greatest.	5 9 3	9
003	Check if a number is a palindrome	palindrome_number.sh	Reverse the number and check if it matches the original.	121	Palindrome
004	Check if a string is a palindrome	palindrome_string.sh	Reverse a string and compare with the original to check for palindrome.	radar	Palindrome
005	Check if a year is leap year or not	leap_year.sh	Determine leap year based on divisibility rules by 4, 100, 400.	2024	Leap Year
006	Check if a number is positive, negative or zero	number_check.sh	Print whether number is positive, negative or zero.	-5	Negative
007	Check if a character is a vowel or consonant	vowel_check.sh	Check if the input character is one of a, e, i, o, u.	e	Vowel
008	Check if a number is prime	prime_check.sh	Use loop to check divisibility and determine if number is prime.	11	Prime
009	Find the smallest of three numbers	smallest_three.sh	Compare three input numbers and print the smallest one.	7 2 5	2
010	Check if a string is empty or not	empty_string.sh	Use -z or -n test to check for empty string input.	""	Empty
011	Display grade based on marks	student_grade.sh	Read marks and assign grades using if-elif.	85	A
012	Check if a number is divisible by both 3 and 5	divisible_3_5.sh	Use modulo to check divisibility by both 3 and 5.	15	Divisible
013	Check if a number is an Armstrong number	armstrong_number.sh	Sum of cube of digits equals the number itself.	153	Armstrong
014	Check if a triangle is valid (angles)	valid_triangle.sh	Sum of three angles should be 180 to be a valid triangle.	60 60 60	Valid Triangle
015	Identify triangle type (equilateral, isosceles, scalene)	triangle_type.sh	Compare sides and print triangle type.	5 5 8	Isosceles
016	Check if a number lies in a given range	number_range.sh	Compare number with lower and upper limits.	15, 10-20	In Range
017	Swap two numbers without a third variable	swap_numbers.sh	Use arithmetic operations to swap values.	5 9	9 5
018	Find absolute value of a number	absolute_value.sh	Convert negative number to positive using condition.	-12	12
019	Find greatest among four numbers	greatest_four.sh	Compare four numbers using nested if conditions.	4 7 2 9	9
020	Check if a year has 53 Sundays	fiftythree_sundays.sh	Use date logic or modular arithmetic to determine extra Sundays.	2023	No
021	Print all even numbers from 1 to 50	even_numbers.sh	Loop through range and print numbers divisible by 2.	1-50	2 4 6 ... 50
022	Print multiplication table of a number	multiplication_table.sh	Display table from 1 to 10 for given number.	5	5 10 15 ... 50
023	Find factorial of a number	factorial.sh	Use loop or recursion to compute factorial.	5	120
024	Print Fibonacci series up to N terms	fibonacci.sh	Generate Fibonacci numbers iteratively.	7	0 1 1 2 3 5 8
025	Find sum of digits of a number	sum_digits.sh	Extract each digit and accumulate the sum.	1234	10
026	Reverse a string	reverse_string.sh	Reverse string using loops or rev command.	hello	olleh
027	Count number of vowels in a string	count_vowels.sh	Loop through string and count a, e, i, o, u.	OpenAI	3
028	Count number of words in a string	count_words.sh	Use wc or loop to count words.	Hello world	2
029	Count number of characters in a string	count_chars.sh	Use wc or loop to count characters.	Bash	4
030	Find sum of natural numbers up to N	sum_natural.sh	Use loop or formula to compute sum.	5	15
031	Print first N odd numbers	odd_numbers.sh	Loop to print numbers with modulo 2 != 0.	5	1 3 5 7 9
032	Find HCF of two numbers	hcf.sh	Use Euclidean algorithm with loops.	12 18	6
033	Find LCM of two numbers	lcm.sh	Use formula LCM = (a*b)/HCF(a,b).	4 5	20
034	Convert Celsius to Fahrenheit	celsius_to_fahrenheit.sh	Use formula F = C*9/5 +32.	25	77
035	Convert Fahrenheit to Celsius	fahrenheit_to_celsius.sh	Use formula C = (F-32)*5/9.	77	25
036	Check if a number is perfect	perfect_number.sh	Sum of proper divisors equals the number.	6	Perfect Number
037	Print ASCII value of a character	ascii_value.sh	Use printf or awk to get ASCII value.	A	65
038	Find GCD of multiple numbers	gcd_multiple.sh	Apply HCF iteratively on multiple numbers.	12 18 24	6
039	Find LCM of multiple numbers	lcm_multiple.sh	Compute LCM iteratively using formula.	4 5 6	60
040	Find sum of first N even numbers	sum_even.sh	Loop through first N even numbers to sum.	5	30
041	Find sum of first N odd numbers	sum_odd.sh	Loop through first N odd numbers to sum.	5	25
042	Check if two strings are anagrams	anagram_check.sh	Sort strings and compare for equality.	listen silent	Anagram
043	Count number of lines in a file	count_lines.sh	Use wc -l to count lines.	file.txt	20
044	Count number of words in a file	count_words_file.sh	Use wc -w to count words in file.	file.txt	100
045	Count number of characters in a file	count_chars_file.sh	Use wc -m or awk.	file.txt	450
046	Find largest element in array	largest_array.sh	Loop through array to find maximum.	5 9 3 7	9
047	Find smallest element in array	smallest_array.sh	Loop through array to find minimum.	5 9 3 7	3
048	Sum of array elements	sum_array.sh	Loop through array and add elements.	1 2 3 4	10
049	Reverse an array	reverse_array.sh	Print array elements in reverse order.	1 2 3 4	4 3 2 1
050	Find second largest element in array	second_largest.sh	Track largest and second largest while looping.	1 5 3 7	5
051	Check if a number is a square number	square_number.sh	Determine if square of an integer equals the number.	25	Square Number
052	Check if a number is a cube number	cube_number.sh	Determine if cube of an integer equals the number.	27	Cube Number
053	Print prime numbers between 1 to N	prime_range.sh	Loop from 1 to N and check each number for primality.	10	2 3 5 7
054	Print all Fibonacci numbers less than N	fibonacci_less_n.sh	Generate Fibonacci numbers until N-1.	10	0 1 1 2 3 5 8
055	Find sum of squares of first N natural numbers	sum_squares.sh	Sum i^2 for i from 1 to N.	3	14
056	Find sum of cubes of first N natural numbers	sum_cubes.sh	Sum i^3 for i from 1 to N.	3	36
057	Print all multiples of a number less than N	multiples.sh	Loop and print multiples less than N.	3 10	3 6 9
058	Check if a number is automorphic	automorphic.sh	Square of number ends with same digits as number.	25	Automorphic
059	Find digital root of a number	digital_root.sh	Sum digits repeatedly until single digit.	987	6
060	Count frequency of characters in string	char_frequency.sh	Loop through string and count each character.	hello	h:1 e:1 l:2 o:1
061	Print all divisors of a number	divisors.sh	Loop from 1 to N and print divisors.	12	1 2 3 4 6 12
062	Check if a number is abundant	abundant.sh	Sum of proper divisors greater than number.	12	Abundant
063	Check if a number is deficient	deficient.sh	Sum of proper divisors less than number.	8	Deficient
064	Print all perfect numbers less than N	perfect_numbers.sh	Loop to find numbers whose sum of divisors equals number.	30	6 28
065	Find sum of digits at even positions	sum_even_digits.sh	Sum digits at even indices in number.	1234	6
066	Find sum of digits at odd positions	sum_odd_digits.sh	Sum digits at odd indices in number.	1234	4
067	Convert decimal to binary	decimal_to_binary.sh	Use division-remainder method to convert decimal.	10	1010
068	Convert binary to decimal	binary_to_decimal.sh	Use positional weights to compute decimal.	1010	10
069	Convert decimal to octal	decimal_to_octal.sh	Divide repeatedly by 8 to get octal.	64	100
070	Convert decimal to hexadecimal	decimal_to_hex.sh	Divide repeatedly by 16 for hexadecimal.	255	FF
071	Convert hexadecimal to decimal	hex_to_decimal.sh	Multiply each hex digit by power of 16.	FF	255
072	Reverse words in a sentence	reverse_words.sh	Split sentence and reverse order of words.	Hello world	world Hello
073	Count number of uppercase letters	count_upper.sh	Loop string and check A-Z.	OpenAI	2
074	Count number of lowercase letters	count_lower.sh	Loop string and check a-z.	OpenAI	4
075	Count number of digits in a string	count_digits.sh	Loop string and check 0-9.	OpenAI123	3
076	Count number of special characters in string	count_special.sh	Loop string and count non-alphanumeric.	Open@AI!	2
077	Merge two arrays	merge_arrays.sh	Combine elements of two arrays into one.	1 2, 3 4	1 2 3 4
078	Find intersection of two arrays	array_intersection.sh	Print elements present in both arrays.	1 2 3, 2 3 4	2 3
079	Find union of two arrays	array_union.sh	Print unique elements from both arrays.	1 2, 2 3	1 2 3
080	Remove duplicates from array	remove_duplicates.sh	Keep unique elements only.	1 2 2 3	1 2 3
081	Rotate array left by N positions	rotate_left.sh	Shift array elements left N times.	1 2 3 4 1	2 3 4 1 1
082	Rotate array right by N positions	rotate_right.sh	Shift array elements right N times.	1 2 3 4 1	1 1 2 3 4
083	Check if array is sorted	check_sorted.sh	Loop and compare consecutive elements.	1 2 3 4	Sorted
084	Find maximum difference in array	max_diff.sh	Subtract min from max in array.	1 2 5 3	4
085	Print all prime factors of a number	prime_factors.sh	Divide by primes iteratively.	12	2 2 3
086	Find sum of prime numbers less than N	sum_primes.sh	Loop and sum all primes < N.	10	17
087	Print all palindrome numbers less than N	palindrome_numbers.sh	Check each number for palindrome.	100	0 1 2 3 ... 99
088	Count number of zeros in a number	count_zeros.sh	Extract digits and count zeros.	10203	2
089	Find next prime number	next_prime.sh	Increment and check primality.	10	11
090	Find previous prime number	prev_prime.sh	Decrement and check primality.	10	7
091	Find all Armstrong numbers less than N	armstrong_less_n.sh	Check each number for Armstrong property.	500	0 1 153 370 371 407
092	Count total digits in a number	total_digits.sh	Divide by 10 until 0.	12345	5
093	Print a pattern of stars	star_pattern.sh	Use nested loops to print triangle/star patterns.	5	* \n ** \n *** ...
094	Print reverse pattern of stars	reverse_star.sh	Nested loops for inverted triangle.	5	***** \n **** ...
095	Print hollow square pattern	hollow_square.sh	Print stars on edges only.	4	**** \n * * \n * * \n ****
096	Find sum of first N odd numbers using formula	sum_odd_formula.sh	Sum = N^2	5	25
097	Find sum of first N even numbers using formula	sum_even_formula.sh	Sum = N*(N+1)	5	30
098	Print Pascal's triangle up to N rows	pascals_triangle.sh	Use combination formula in nested loops.	5	1 \n 1 1 \n 1 2 1 ...
099	Find sum of squares of digits of a number	sum_squares_digits.sh	Loop through digits and sum squares.	23	13
100	Find product of digits of a number	product_digits.sh	Multiply all digits together.	123	6

Hacktoberfest 2025 Bash Challenge - Steps

1. Pick Questions
   Click the provided link and get 3 question IDs you want to solve.

2. Fork Repository
   Fork the main repository to your GitHub account.

3. Solve Problems
   Solve the picked problems one by one using Bash scripting.

   • Use the file names mentioned in the question list to create files for respective questions.
   • Commit your code to your forked repository.

4. Create Pull Requests
   Make pull requests one by one for each solved problem.

5. Update Comments
   Once your pull requests are merged:

   • Update the comments/documentation in all three programs.
   • Commit the changes to your forked repository.

6. Pull Requests for Updated Changes
   Make pull requests again, one by one, for the updated comments/documentation.

7. Completion
   Once all 6 pull requests are merged, Hacktoberfest 2025 will be completed and updated on the Hacktoberfest site.