DEV Community: Fahad Vahora

Linux Practical Set A Solution – Simple Interest & Compound Interest

Fahad Vahora — Sun, 09 Aug 2026 05:55:13 +0000

In this article, we will solve VNSGU TYBCA Semester 5 Linux (UNIX) Practical – Set A using shell scripting.

We will calculate:

Simple Interest (SI)
Compound Interest (CI)
Total Amount

We will also see different approaches, including solutions with bc and without bc.

📌 Practical Question

Write a shell script to calculate the Simple Interest and Compound Interest for given amount.

📐 Formulas

Simple Interest

SI = (P × R × T) / 100

Where:

P = Principal Amount
R = Rate of Interest
T = Time

Simple Interest Amount

Amount = P + SI

Compound Interest

For annual compounding:

CI = P × (1 + R/100)^T - P

Compound Amount

CA = P × (1 + R/100)^T

✅ Solution 1: Using `bc`

bc is a command-line calculator available on Linux/UNIX systems.

It is useful when we need decimal calculations in shell scripts.

Shell Script

#!/bin/bash

echo "Enter Principal Amount:"
read P

echo "Enter Rate of Interest (%):"
read R

echo "Enter Time (in years):"
read T

SI=$(echo "scale=2; ($P * $R * $T) / 100" | bc)

CA=$(echo "scale=2; $P * (1 + $R / 100)^$T" | bc)

CI=$(echo "scale=2; $CA - $P" | bc)

echo "-----------------------------"
echo "Principal Amount : $P"
echo "Rate of Interest : $R%"
echo "Time             : $T years"
echo "Simple Interest  : $SI"
echo "Compound Interest: $CI"
echo "Compound Amount  : $CA"
echo "-----------------------------"

Example Output

Enter Principal Amount:
10000

Enter Rate of Interest (%):
10

Enter Time (in years):
2

-----------------------------
Principal Amount : 10000
Rate of Interest : 10%
Time             : 2 years
Simple Interest  : 2000.00
Compound Interest: 2100.00
Compound Amount  : 12100.00
-----------------------------

How it works

SI=$(echo "scale=2; ($P * $R * $T) / 100" | bc)

Here, bc performs the decimal calculation.

scale=2

means that the result can contain 2 digits after the decimal point.

For compound interest:

CA=$(echo "scale=2; $P * (1 + $R / 100)^$T" | bc)

The ^ operator is used for exponentiation.

✅ Solution 2: Without `bc`

Bash's normal arithmetic expansion:

$(( ... ))

works with integers, not floating-point numbers.

Therefore, if the practical only requires integer input and integer output, we can calculate SI and CI using Bash arithmetic.

Shell Script

#!/bin/bash

echo "Enter Principal Amount:"
read P

echo "Enter Rate of Interest (%):"
read R

echo "Enter Time (in years):"
read T

SI=$((P * R * T / 100))

AMOUNT=$P
for ((i=1; i<=T; i++))
do
    AMOUNT=$((AMOUNT * (100 + R) / 100))
done

CI=$((AMOUNT - P))

echo "-----------------------------"
echo "Principal Amount : $P"
echo "Rate of Interest : $R%"
echo "Time             : $T years"
echo "Simple Interest  : $SI"
echo "Compound Interest: $CI"
echo "Compound Amount  : $AMOUNT"
echo "-----------------------------"

Example

For:

P = 10000
R = 10
T = 2

Output:

Simple Interest  : 2000
Compound Interest: 2100
Compound Amount  : 12100

Important Note

This method uses Bash integer arithmetic.

For example:

$((10 / 3))

produces:

not:

3.3333

So this method is suitable when decimal precision is not required.

✅ Solution 3: Using `awk`

If you don't want to use bc but still want decimal calculations, awk is a very good alternative.

Shell Script

#!/bin/bash

echo "Enter Principal Amount:"
read P

echo "Enter Rate of Interest (%):"
read R

echo "Enter Time (in years):"
read T

awk -v P="$P" -v R="$R" -v T="$T" '
BEGIN {
    SI = (P * R * T) / 100
    CA = P * (1 + R / 100)^T
    CI = CA - P

    printf "-----------------------------\n"
    printf "Principal Amount : %.2f\n", P
    printf "Rate of Interest : %.2f%%\n", R
    printf "Time             : %d years\n", T
    printf "Simple Interest  : %.2f\n", SI
    printf "Compound Interest: %.2f\n", CI
    printf "Compound Amount  : %.2f\n", CA
    printf "-----------------------------\n"
}'

Example Output

Enter Principal Amount:
10000

Enter Rate of Interest (%):
10

Enter Time (in years):
2

-----------------------------
Principal Amount : 10000.00
Rate of Interest : 10.00%
Time             : 2 years
Simple Interest  : 2000.00
Compound Interest: 2100.00
Compound Amount  : 12100.00
-----------------------------

🔍 Difference Between the Solutions

Method	Decimal Support	Easy to Understand	External Command
`bc`	✅ Yes	⭐⭐⭐	`bc`
Bash arithmetic	❌ Integer only	⭐⭐⭐⭐	No
`awk`	✅ Yes	⭐⭐	`awk`

Which one should you use?

For a Linux practical examination:

If bc is allowed: use the bc solution.

If bc is not allowed: use the Bash arithmetic solution when integer output is acceptable.

If decimal output is required but bc is not allowed: use awk.

🧠 Important Shell Concepts Used

This practical helps you practice several important shell scripting concepts:

1. Taking Input

read P

2. Arithmetic Expansion

$(( ... ))

3. Command Substitution

SI=$(...)

4. `bc`

Used for floating-point calculations.

5. `awk`

Can perform floating-point calculations and formatted output.

6. `for` Loop

Used in the pure Bash compound-interest solution.

🎯 Practical Exam Tip

Don't just memorize the script.
Understand these three things:

1. How to take input
2. How to apply the SI and CI formulas
3. How to display the result

Once you understand these, you can easily modify the program if the examiner changes the question slightly.

📚 Related Article

This solution is part of the VNSGU TYBCA Sem 5 Linux (UNIX) Practical – OCT/Nov 2025 series.

You can also practice the other practical sets:

Set A – Simple Interest & Compound Interest
Set B – Vowels & Case Conversion
Set C – Palindrome
Set D – File Operations
Set E – Display Lines with Validation
Set F – Files & Directories
Set G – Recently Modified Files
Set H – Employee Gross Salary

⚠️ Note

The Compound Interest calculation in this article assumes annual compounding.

The Bash-only solution uses integer arithmetic, so decimal precision may differ from the bc or awk versions.

🐧 Conclusion

The Simple Interest and Compound Interest problem is a good beginner-level shell scripting practical because it combines user input, arithmetic operations, variables, loops, and command-line utilities.

Practice all three approaches so that you are comfortable solving the question even when the examination environment has different restrictions.

Happy Learning & Best of Luck for your Linux Practical! 🐧💻

VNSGU TYBCA Linux(Unix) Semester 5 OCT/Nov 2025 Practical Question Papers Sets

Fahad Vahora — Sun, 09 Aug 2026 05:46:56 +0000

VNSGU TYBCA Sem 5 Linux (UNIX) Practical Question Paper – OCT/Nov 2025

Are you preparing for the VNSGU TYBCA Semester 5 Linux (UNIX) Practical Examination?

This article contains the Linux (UNIX) Shell Scripting Practical Question Paper Sets A to H for the OCT/Nov 2025 examination.

These practical sets cover important topics such as shell scripting, string handling, file handling, command-line arguments, file searching, validation, and arithmetic operations.

📚 VNSGU TYBCA Sem 5 – Linux (UNIX)

Details	Information
University	Veer Narmad South Gujarat University (VNSGU)
Course	TYBCA
Semester	Semester 5
Subject	Linux (UNIX)
Exam	OCT/Nov 2025
Type	Practical Examination
Sets	A to H

🐧 Linux (UNIX) Practical Question Sets

📌 Set A – Simple Interest & Compound Interest

Write a shell script to calculate the Simple Interest and Compound Interest for given amount.

📌 Set B – Vowels Count & Case Conversion

Write a script to count the number of vowels in the entered string and convert the string into upper case or lower case.

📌 Set C – Palindrome String

Write a script to check whether a given string is palindrome or not.

📌 Set D – File Operations & Text Processing

Write a shell script to perform following:

Create a file named marks.txt and insert 5 lines of text.
Display the first 3 lines of marks.txt.
Display the last 2 lines of marks.txt.
Count the number of words, lines, and characters in marks.txt.
Search for the word Linux in marks.txt.

Commands Covered

cat
head
tail
wc
grep

📌 Set E – Display Specific Lines from File

Write a shell script that will pass file name and two numbers a1 and a2. Display line a1 to a2 from that file.

Proper validation required.

The script should properly validate the input and handle invalid arguments or file names.

Concepts Covered

Command-line arguments
File validation
Line numbers
sed
Input validation

📌 Set F – Count Files and Directories

Write a shell script to find total number of files and total number of directories in current working directory.

Concepts Covered

Directory handling
File testing
Loops
find
Current working directory

📌 Set G – Recently Modified Files

Write a shell script to find all files in the current directory that were modified in the last 7 days and display their names and sizes.

Concepts Covered

File searching
Modification time
find
File size
Shell scripting

📌 Set H – Employee Gross Salary

Write a shell script that computes the gross salary of an employee according to the following:

If Basic Salary is < 50000

HRA = 20% of Basic Salary
DA = 164% of Basic Salary

If Basic Salary is > 50000

HRA = 15% of Basic Salary
DA = 136% of Basic Salary

Input

The basic salary should be entered interactively through the keyboard.

Formula

Gross Salary = Basic Salary + DA + HRA

📖 Topics Covered in These Practical Sets

These eight practical sets cover several important Linux and UNIX shell scripting concepts:

Shell Scripting
Variables
User Input
Arithmetic Operations
if-else
Loops
String Handling
String Case Conversion
Palindrome Checking
File Handling
Command-Line Arguments
File Validation
Text Processing
head
tail
wc
grep
find
File Size
File Modification Time
Input Validation

🎯 Linux Practical Exam Preparation Tips

If you are preparing for the VNSGU TYBCA Linux practical examination, practice each set yourself instead of only memorizing the script.

1. Understand Shell Syntax

Practice basic shell scripting syntax such as:

#!/bin/bash

variables, read, conditions, loops, and command substitution.

2. Practice Linux Commands

Make sure you are comfortable with commands such as:

cat
head
tail
wc
grep
find
cut
tr
sed

3. Practice Validation

For programs involving files or command-line arguments, always check:

Whether the required arguments are provided
Whether the file exists
Whether the file is readable
Whether the entered values are valid

4. Practice Without Copy-Paste

Try writing every program from scratch. This will help you understand the logic and make it easier to solve variations of the same question during the practical exam.

📝 Quick Revision

Set	Practical Topic
A	Simple Interest & Compound Interest
B	Vowels Count & Case Conversion
C	Palindrome String
D	File Operations & Text Processing
E	Display Lines with Validation
F	Count Files & Directories
G	Recently Modified Files
H	Employee Gross Salary

📌 Conclusion

These VNSGU TYBCA Semester 5 Linux (UNIX) Practical Sets A–H cover a useful range of shell scripting problems for practical examination preparation.

Students should practice each program on a Linux/UNIX environment and understand the logic behind every command and statement.

All the best for your Linux (UNIX) Practical Examination! 🐧💻

⚠️ Disclaimer

This article is intended for educational and examination preparation purposes. Students should verify official examination details and question papers with the relevant VNSGU sources.

DEV Community: Fahad Vahora

Linux Practical Set A Solution – Simple Interest & Compound Interest

📌 Practical Question

📐 Formulas

Simple Interest

Simple Interest Amount

Compound Interest

Compound Amount

✅ Solution 1: Using bc

Shell Script

Example Output

How it works

✅ Solution 2: Without bc

Shell Script

Example

Important Note

✅ Solution 3: Using awk

Shell Script

Example Output

🔍 Difference Between the Solutions

Which one should you use?

🧠 Important Shell Concepts Used

1. Taking Input

2. Arithmetic Expansion

3. Command Substitution

4. bc

5. awk

6. for Loop

🎯 Practical Exam Tip

📚 Related Article

⚠️ Note

🐧 Conclusion

VNSGU TYBCA Linux(Unix) Semester 5 OCT/Nov 2025 Practical Question Papers Sets

VNSGU TYBCA Sem 5 Linux (UNIX) Practical Question Paper – OCT/Nov 2025

📚 VNSGU TYBCA Sem 5 – Linux (UNIX)

🐧 Linux (UNIX) Practical Question Sets

📌 Set A – Simple Interest & Compound Interest

📌 Set B – Vowels Count & Case Conversion

📌 Set C – Palindrome String

📌 Set D – File Operations & Text Processing

Commands Covered

📌 Set E – Display Specific Lines from File

Concepts Covered

📌 Set F – Count Files and Directories

Concepts Covered

📌 Set G – Recently Modified Files

Concepts Covered

📌 Set H – Employee Gross Salary

If Basic Salary is < 50000

If Basic Salary is > 50000

Input

Formula

📖 Topics Covered in These Practical Sets

🎯 Linux Practical Exam Preparation Tips

1. Understand Shell Syntax

2. Practice Linux Commands

3. Practice Validation

4. Practice Without Copy-Paste

📝 Quick Revision

📌 Conclusion

⚠️ Disclaimer

✅ Solution 1: Using `bc`

✅ Solution 2: Without `bc`

✅ Solution 3: Using `awk`

4. `bc`

5. `awk`

6. `for` Loop