Linux Find Command.md

Simplified Python Implementation of the Linux Find Command

This document describes the design and implementation of a simplified version of the Linux find command in Python. This script provides functionality to search for files based on specific filters such as minimum size and file extension.

Classes and Functions

File Class

Represents a file or directory in the system.

class File:
    def __init__(self, name, size):
        self.name = name
        self.size = size
        self.children = []
        self.is_directory = False if '.' in name else True
        self.extension = name.split(".")[1] if '.' in name else ""

    def __repr__(self):
        return "{" + self.name + "}"

Abstract Filter Class

Defines an interface for filters.

from abc import ABC, abstractmethod

class Filter(ABC):
    @abstractmethod
    def apply(self, file):
        pass

MinSizeFilter Class

Filters files that are larger than a specified size.

class MinSizeFilter(Filter):
    def __init__(self, size):
        self.size = size

    def apply(self, file):
        return file.size > self.size

ExtensionFilter Class

class ExtensionFilter(Filter):
    def __init__(self, extension):
        self.extension = extension

    def apply(self, file):
        return file.extension == self.extension

LinuxFind Class

Implements the core functionality of the Linux find command.

from collections import deque
from typing import List

class LinuxFind():
    def __init__(self):
        self.filters: List[Filter] = []

    def add_filter(self, given_filter):
        self.filters.append(given_filter)

    def apply_OR_filtering(self, root):
        found_files = []
        queue = deque([root])
        while queue:
            current = queue.popleft()
            if current.is_directory:
                queue.extend(current.children)
            else:
                if any(f.apply(current) for f in self.filters):
                    found_files.append(current)
        return found_files

    def apply_AND_filtering(self, root):
        found_files = []
        queue = deque([root])
        while queue:
            current = queue.popleft()
            if current.is_directory:
                queue.extend(current.children)
            else:
                if all(f.apply(current) for f in self.filters):
                    found_files.append(current)
        return found_files

Example Usage

def main():

    f1 = File("root_300", 300)
    f2 = File("fiction_100", 100)
    f3 = File("action_100", 100)
    f4 = File("comedy_100", 100)
    f1.children = [f2, f3, f4]

    f5 = File("StarTrek_4.txt", 4)
    f6 = File("StarWars_10.xml", 10)
    f7 = File("JusticeLeague_15.txt", 15)
    f8 = File("Spock_1.jpg", 1)
    f2.children = [f5, f6, f7, f8]

    f9 = File("IronMan_9.txt", 9)
    f10 = File("MissionImpossible_10.rar", 10)
    f11 = File("TheLordOfRings_3.zip", 3)
    f3.children = [f9, f10, f11]

    f11 = File("BigBangTheory_4.txt", 4)
    f12 = File("AmericanPie_6.mp3", 6)
    f4.children = [f11, f12]


    greater5_filter = MinSizeFilter(5)
    txt_filter = ExtensionFilter("txt")

    my_linux_find = LinuxFind()
    my_linux_find.add_filter(greater5_filter)
    my_linux_find.add_filter(txt_filter)

    print(my_linux_find.apply_OR_filtering(f1))
    print(my_linux_find.apply_AND_filtering(f1))

if __name__ == "__main__":
    main()

edit