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Linux Programming Practical Lab Programs (BCA & CS)

Welcome to the complete practical lab manual for Linux Programming. Below are university-tested solutions for practical examinations in BCA, B.Tech, and MCA curricula.

Program 1: Find the Largest of Three Numbers

#!/bin/bash
# Find greatest among 3 numbers entered by user

echo -n "Enter three numbers: "
read n1 n2 n3

if [ $n1 -ge $n2 ] && [ $n1 -ge $n3 ]; then
    max=$n1
elif [ $n2 -ge $n1 ] && [ $n2 -ge $n3 ]; then
    max=$n2
else
    max=$n3
fi

echo "The greatest number is: $max"
							

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Program 2: Check Whether a Year is a Leap Year

#!/bin/bash
# A year is a leap year if divisible by 400 OR (divisible by 4 and not by 100)

echo -n "Enter year (YYYY): "
read year

if [ $((year % 400)) -eq 0 ] || [ $((year % 4)) -eq 0 -a $((year % 100)) -ne 0 ]; then
    echo "$year is a Leap Year!"
else
    echo "$year is NOT a Leap Year."
fi
							

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Program 3: Check If a Number is Prime

#!/bin/bash
# Check Prime Number

echo -n "Enter integer: "
read num

if [ $num -le 1 ]; then
    echo "$num is neither prime nor composite."
    exit 0
fi

is_prime=1
for (( i=2; i*i<=num; i++ ))
do
    if [ $((num % i)) -eq 0 ]; then
        is_prime=0
        break
    fi
done

if [ $is_prime -eq 1 ]; then
    echo "$num is a PRIME number."
else
    echo "$num is NOT a prime number."
fi
							

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Program 4: Generate Fibonacci Series up to N Terms

#!/bin/bash
# Fibonacci Series: 0, 1, 1, 2, 3, 5, 8, ...

echo -n "Enter number of terms N: "
read n

a=0
b=1

echo "Fibonacci Series up to $n terms:"
for (( i=0; i<n; i++ ))
do
    echo -n "$a "
    fn=$(( a + b ))
    a=$b
    b=$fn
done
echo ""
							

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Program 5: Check String Palindrome

#!/bin/bash
# Palindrome string checker (e.g., 'madam', 'racecar')

echo -n "Enter a word/string: "
read str

# Reverse string using rev utility
rev_str=$(echo "$str" | rev)

if [ "$str" = "$rev_str" ]; then
    echo "'$str' is a PALINDROME!"
else
    echo "'$str' is NOT a palindrome."
fi
							

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Program 6: Count Lines, Words, and Characters in a File

#!/bin/bash
# File stats analyzer

echo -n "Enter file path to analyze: "
read filepath

if [ ! -f "$filepath" ]; then
    echo "Error: File does not exist!"
    exit 1
fi

lines=$(wc -l < "$filepath")
words=$(wc -w < "$filepath")
chars=$(wc -m < "$filepath")

echo "--------------------------------"
echo "Analysis for: $filepath"
echo "Total Lines      : $lines"
echo "Total Words      : $words"
echo "Total Characters : $chars"
echo "--------------------------------"
							

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Program 7: C System Call - Parent and Child with fork()

/*
 * fork_lab.c - University Practical Exam Program
 * Compile: gcc fork_lab.c -o fork_lab
 */

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main() {
    pid_t pid = fork();

    if (pid < 0) {
        printf("Error: Fork creation failed!\n");
        return 1;
    } else if (pid == 0) {
        printf("[CHILD PROCESS]  My PID = %d, Parent PPID = %d\n", getpid(), getppid());
    } else {
        wait(NULL); // Parent waits for child
        printf("[PARENT PROCESS] My PID = %d, Child PID = %d\n", getpid(), pid);
    }

    return 0;
}
							

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Program 8: C System Call - Half-Duplex IPC Pipe

/*
 * pipe_lab.c - Communication between parent and child via pipe()
 * Compile: gcc pipe_lab.c -o pipe_lab
 */

#include <stdio.h>
#include <unistd.h>
#include <string.h>

int main() {
    int pfd[2];
    char inbuf[50];
    char msg[] = "Veewom Practical Exam IPC";

    pipe(pfd);

    if (fork() == 0) {
        // Child reads from pfd[0]
        close(pfd[1]);
        read(pfd[0], inbuf, sizeof(inbuf));
        printf("Child received message: %s\n", inbuf);
        close(pfd[0]);
    } else {
        // Parent writes to pfd[1]
        close(pfd[0]);
        write(pfd[1], msg, strlen(msg) + 1);
        close(pfd[1]);
    }

    return 0;
}
							

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