CBSE Class 7 Computer Science Assignment Set 01

Question 1. Give the full form of Bash, PID.
Answer: Bash stands for Bourne Again SHell.
PID stands for Process ID.
In simple words: Bash is a command processor in Unix, and PID is a unique number given to every active program.

Exam Tip: Memorize exact full forms as spelling errors in acronym expansions result in loss of marks.

Question 2. Is anything wrong with each of the following commands? If yes, specify.
(a) ls -l-s
(b) rmdir-r Friends
Answer:
(a) Yes, there should be a space or options should be combined correctly, or multiple single-letter options should follow a single hyphen like \(\text{ls -ls}\).
(b) Yes, there is a space missing between the command and the option. It should be written as \(\text{rmdir -r Friends}\) or \(\text{rm -r Friends}\) since \(\text{rmdir}\) is typically used for empty directories without the \(-r\) recursive flag in some contexts, whereas \(\text{rm -r}\) removes directories recursively.
In simple words: Commands and options in Linux must follow correct spacing and valid flag syntax.

Exam Tip: Pay close attention to spacing between command names, flags, and arguments.

Question 3. Differentiate between any two of the following:
(a) Home directory and current directory
(b) Moving and Copying files
(c) Kernel and Shell
Answer:
Difference between Kernel and Shell:
- Kernel: It is the core component of the Linux operating system that manages system resources, hardware, and memory.
- Shell: It is a user interface that interprets user commands and sends them to the kernel to be executed.
Difference between Moving and Copying files:
- Moving files: Relocates a file from the source location to a destination location, removing it from the original place.
- Copying files: Creates a duplicate of the file at the destination location while keeping the original file intact.
In simple words: Kernel handles core hardware, Shell takes user commands; moving shifts a file, copying duplicates it.

Exam Tip: Use comparative bullet points with clear headings when asked to differentiate.

Question 4. Explain any 2 features of Linux.
Answer: Two main features of Linux are:
1. Open Source: The source code of Linux is freely available to the public, allowing users to view, modify, and distribute it.
2. Multi-user and Multitasking: Linux allows multiple users to work simultaneously on the same system and permits a single user to run multiple programs at the same time.
In simple words: Linux is free to modify and lets many users run multiple programs at once.

Exam Tip: Always state the feature name in bold followed by a brief 1-2 line explanation.

Question 5. (a) What is the advantage of open source software? Explain using an example.
(b) What are the conditions required to delete a directory? Mention any 2 conditions.
Answer:
(a) The primary advantage of open source software is transparency, flexibility, and cost-effectiveness. Users can inspect the code for security vulnerabilities and customize it to suit their needs. For example, Linux is an open source operating system that allows developers worldwide to modify and improve its source code.
(b) Two conditions required to delete a directory using standard commands like \(\text{rmdir}\) are:
1. The directory must be completely empty (contain no files or subdirectories).
2. The user must have write and execute permissions for the parent directory.
In simple words: Open source lets you view and change code freely; deleting a standard directory requires it to be empty.

Exam Tip: Give a real-world example when asked to explain software concepts.

Question 6. WAP to store 10 numbers in an array and print the cube of numbers placed at odd subscript positions.
Answer:
#include <stdio.h>
int main() {
    int arr[10], i;
    printf("Enter 10 numbers:\n");
    for(i = 0; i < 10; i++) {
        scanf("%d", &arr[i]);
    }
    printf("Cubes of numbers at odd subscripts:\n");
    for(i = 1; i < 10; i += 2) {
        int cube = arr[i] * arr[i] * arr[i];
        printf("Index %d: %d\n", i, cube);
    }
    return 0;
}

In simple words: The program takes 10 inputs, loops through odd index positions (\(1, 3, 5, \dots\)), and calculates their cubes.

Exam Tip: Remember that array indexing usually starts from 0, so odd subscripts are 1, 3, 5, etc.

Question 7. WAP to multiply the values of 2 single dimensional arrays of size 5 each. Display the result.
Answer:
#include <stdio.h>
int main() {
    int a[5], b[5], prod[5], i;
    printf("Enter 5 elements for first array:\n");
    for(i = 0; i < 5; i++) {
        scanf("%d", &a[i]);
    }
    printf("Enter 5 elements for second array:\n");
    for(i = 0; i < 5; i++) {
        scanf("%d", &b[i]);
    }
    printf("Product of corresponding elements:\n");
    for(i = 0; i < 5; i++) {
        prod[i] = a[i] * b[i];
        printf("%d ", prod[i]);
    }
    return 0;
}

In simple words: Multiply corresponding elements of two arrays using a loop and store/display the results.

Question 8. Consider the following file system structure and write Linux commands to:
(a) Rename the file Mycar.doc to My.doc
(b) Create a new directory Mazda under the directory Buses
(c) Copy the file Mycar.doc to Alto.doc under Volkswagen
(d) Remove the file Mycar.doc
Answer:
Based on the file system hierarchy (assuming current working directory contains the relevant paths or absolute paths are used):
(a) \(\text{mv Mycar.doc My.doc}$ or assuming path: \(\text{mv /Root/Cars/Maruti/Swift/Mycar.doc /Root/Cars/Maruti/Swift/My.doc}\)
(b) \(\text{mkdir /Root/Buses/Mazda}\)
(c) \(\text{cp /Root/Cars/Maruti/Swift/Mycar.doc /Root/Cars/Volkswagen/Alto.doc}\)
(d) \(\text{rm /Root/Cars/Maruti/Swift/Mycar.doc}\)
In simple words: Use \(\text{mv}\) for renaming/moving, \(\text{mkdir}\) for making directories, \(\text{cp}\) for copying, and \(\text{rm}\) for deleting files.
Exam Tip: Double-check source and destination paths when manipulating files in nested directory trees.