2a

#!/bin/sh
echo "10 levels of folders are created for the departments and 10 levels of files created for student details"
i=1
while [ $i -le 10 ]
do
    mkdir MSRITDept$i
    cd MSRITDept$i
    j=1
    while [ $j -le 10 ]
    do
        touch MSRITStudentDetails$j
        j=$(($j+1))
    done
    cd ..
    i=$(($i+1))
done

2b

#! /bin/bash

if [ $# -eq 0 ]
then
    echo "Display does not exist"
else
    ls -l $1 > t1
    x=`cut -d ' ' -f 1,6,7,8,9 t1`
    echo $x
fi

3a

#!/bin/bash

for i in $*
do
    if [ -d $i ]  
    then
        echo "Large filename size is"
        echo `ls -lR $1 | grep "^." | tr -s ' ' | cut -d ' ' -f 5 | sort -n | tail -l`
    else
        echo "Not a directory"
    fi
done

3b

#!/bin/bash
#cd /home/exam/

filename="rit.txt"

if [ -e $filename ]
then 
    echo "Moving the contents of rit.txt to rit.txt_old"
    mv -f $filename $filename"_old"
    touch $filename
elif [ ! -e $filename ]
then
    echo "File does not exist.. so creating an empty file"
    touch $filename
fi

3d

#!/bin/bash

echo " '\$*' output is $*"
echo " '\$#' output is $#"
echo " '\$1 and \$2' output is $1 and $2"
echo " '\$@' output is $@"
echo " '\$?' output is $?"
echo " '\$!' output is $!"
echo " '\$0' your current program name is $0"

4a

#!/bin/bash

threshold=50
for path in `/bin/df -h | grep -vE 'Filesystem/tmpfs' | awk '{print $5}' | sed 's/%//g'`
do
    echo "$path"
    if [ $path -ge $threshold ]; 
    then
        df -h | grep $path% >> t.txt
        find . -type f -size +500M > w.txt
    fi
done

value=`cat w.txt | wc -l`
if [ $value -ge 1 ];
then
    echo "Yes, the directory contains a file size more than 500M or near to 1GB"
fi

4b

#!/bin/bash
echo "read a string"
read string
words=$(echo -n "$string" | wc -w)
chars=$(echo -n "$string" | wc -c)
space=$(expr length "$string" - length `echo "$string" | sed "s/ //g"`)
specialsymbols=$(echo $string|grep -o [^A-Za-z0-9_[:space:]] | wc -l)
echo "The number of words = $words"
echo "The number of characters = $chars"
echo "The number of white spaces = $space"
echo "The number of special symbols = $specialsymbols"

5a

{split ( $0, arr, "-" )

if ((arr[1] < 1) || (arr[1] > 31) || (arr[2] < 1) || (arr[2] > 12))
{
    print "invalid date"
    exit 0
}
else
{
    if (arr[2] == 1)
        print "January"
    else if (arr[2] == 2)
        print "February"
    else if (arr[2] == 3)
        print "March"
    else if (arr[2] == 4)
        print "April"
    else if (arr[2] == 5)
        print "May"
    else if (arr[2] == 6)
        print "June"
    else if (arr[2] == 7)
        print "July"
    else if (arr[2] == 8)
        print "August"
    else if (arr[2] == 9)
        print "September"
    else if (arr[2] == 10)
        print "October"
    else if (arr[2] == 11)
        print "November"
    else if (arr[2] == 12)
        print "December"

    print arr[1]
    print arr[3]
}
}

5b

BEGIN {
    print "Removing Duplicated lines"
}
{
    line [++no] = $0
}
END {
    for (i = 1 ; i <= no; i++)
    {
        flag = 1
        for (j = 1; j < i; j++)
            if (line[i] == line[j])
                flag = 0
        if(flag == 1)
            print line[i] >>"out.txt"
    }
}

7a

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>

void listFiles(char *path) {
    DIR *dir;
    struct dirent *entry;
    struct stat fileStat;

    // Open the directory
    if ((dir = opendir(path)) == NULL) {
        perror("Error opening directory");
        exit(EXIT_FAILURE);
    }

    // Print header
    printf("%-10s %-8s %-8s %-8s %-12s %s\n", "Permissions", "Links", "Owner", "Group", "Size", "Last Modified");

    // Read each entry in the directory
    while ((entry = readdir(dir)) != NULL) {
        // Construct the full path
        char filePath[1024];
        snprintf(filePath, sizeof(filePath), "%s/%s", path, entry->d_name);

        // Get file status
        if (stat(filePath, &fileStat) < 0) {
            perror("Error getting file status");
            exit(EXIT_FAILURE);
        }

        // Get owner and group names
        struct passwd *owner = getpwuid(fileStat.st_uid);
        struct group *group = getgrgid(fileStat.st_gid);

        // Print file attributes
        printf("%s %2lu %-8s %-8s %8ld %s %s\n",
            (S_ISDIR(fileStat.st_mode)) ? "d" : "-",
            fileStat.st_nlink,
            owner->pw_name,
            group->gr_name,
            fileStat.st_size,
            ctime(&fileStat.st_mtime),
            entry->d_name);
    }

    // Close the directory
    closedir(dir);
}

int main(int argc, char *argv[]) {
    // Check if the correct number of arguments is provided
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <directory>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    // Call the function to list files
    listFiles(argv[1]);
    return 0;
}

7b

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>

void removeEmptyFiles(char *path) {
    DIR *dir;
    struct dirent *entry;
    struct stat fileStat;

    // Open the directory
    if ((dir = opendir(path)) == NULL) {
        perror("Error opening directory");
        exit(EXIT_FAILURE);
    }

    // Read each entry in the directory
    while ((entry = readdir(dir)) != NULL) {
        // Construct the full path
        char filePath[1024];
        snprintf(filePath, sizeof(filePath), "%s/%s", path, entry->d_name);

        // Get file status
        if (stat(filePath, &fileStat) < 0) {
            perror("Error getting file status");
            exit(EXIT_FAILURE);
        }

        // Check if the file is empty and remove it
        if (S_ISREG(fileStat.st_mode) && fileStat.st_size == 0) {
            if (unlink(filePath) == 0) {
                printf("Removed empty file: %s\n", entry->d_name);
            } else {
                perror("Error removing file");
            }
        }
    }

    // Close the directory
    closedir(dir);
}

int main(int argc, char *argv[]) {
    // Check if the correct number of arguments is provided
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <directory>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    // Call the function to remove empty files
    removeEmptyFiles(argv[1]);
    return 0;
}