kernelPractice42Seoul

This repository contains my practice scripts and code from the 42 Seoul kernel and shell curriculum. It includes shell scripting, C programming, and system-level exercises, organized by project and topic.

Granular File List and Practice Topics

• shell00/ex00/z

  • Type: Plain text file (no extension, single character content)
  • Purpose: Practice creating a file with a specific name and content, and understanding file permissions and minimal shell file requirements.
  • Shell Concepts: File creation, naming conventions, permissions, file content.

• shell00/ex01/testShell00.tar

  • Type: tar archive file
  • Purpose: Practice creating and extracting tar archives, understanding file packaging and compression in Unix systems.
  • Shell Concepts: tar command usage, file archiving, compression, extraction, file structure preservation.

• shell00/ex02/ex02.tar

  • Type: tar archive file
  • Purpose: Practice creating and extracting tar archives, understanding file packaging and compression in Unix systems.
  • Shell Concepts: tar command usage, file archiving, compression, extraction, file structure preservation.

• shell00/ex03/klist.txt

  • Type: Plain text file (Kerberos ticket cache output)
  • Purpose: Demonstrate the output of the klist command, which lists Kerberos tickets for the current user/session.
  • Shell/System Concepts: Kerberos authentication, ticket cache, principal, ticket expiration, system security context.

• shell00/ex04/midLS

  • Type: Shell script (single command)
  • Purpose: List directory contents in creation order (not sorted), demonstrating the use of ls with the -U option.
  • Shell Concepts: ls command, -U option for unsorted output, command execution, file listing.

• shell00/ex05/git_commit.sh

  • Type: Shell script (single command)
  • Purpose: Show the last 5 git commit hashes in the current repository.
  • Shell Concepts: git log command, --pretty=format option, limiting output, version control history.
  • Command breakdown:
    • git log --pretty=format:%H -5
      • --pretty=format:%H: show only commit hashes
      • -5: limit to 5 results

• shell00/ex06/git_ignore.sh

  • Type: Shell script (single command)
  • Purpose: List all ignored and untracked files in the git repository.
  • Shell Concepts: git ls-files command, --ignore, --exclude-standard, --others options, understanding .gitignore and repository status.

• shell00/ex07/b

  • Type: Plain text file (sample text content)
  • Purpose: Used for text processing, file manipulation, or as a sample input for shell commands and scripts.
  • Shell Concepts: File content manipulation, text processing, redirection, command-line utilities.

• shell00/ex08/clean

  • Type: Shell script (single command)
  • Purpose: Clean up backup and temporary files (ending with ~ or surrounded by #) in the current directory tree.
  • Shell Concepts: find command, -type f, -name pattern matching, -delete, -print, file cleanup automation.

• shell00/ex09/ft_magic

  • Type: Magic file (for the file command)
  • Purpose: Define a custom file signature so the file utility can recognize files with specific content as a custom type.
  • Shell Concepts: file command, magic file format, custom file type recognition, file signature definition.

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• c00/ex00/ft_putchar.c

  • Type: C source file
  • Purpose: Print a single character to standard output
  • C Concepts: Function definition, character output, use of write
  • Logic: Defines ft_putchar(char c) which calls write(1, &c, 1);

• c00/ex01/ft_print_alphabet.c

  • Type: C source file
  • Purpose: Print the lowercase English alphabet
  • C Concepts: Function definition, character variables, loops, ASCII values
  • Logic: Loops from 'a' to 'z', printing each character with write

• c00/ex02/ft_print_reverse_alphabet.c

  • Type: C source file
  • Purpose: Print the lowercase English alphabet in reverse
  • C Concepts: Function definition, character variables, loops, ASCII values
  • Logic: Loops from 'z' to 'a', printing each character with write

• c00/ex03/ft_print_numbers.c

  • Type: C source file
  • Purpose: Print the digits 0 through 9
  • C Concepts: Function definition, integer variables, loops, ASCII values
  • Logic: Loops from '0' to '9', printing each digit with write

• c00/ex04/ft_is_negative.c

  • Type: C source file
  • Purpose: Print 'N' if a number is negative, 'P' otherwise
  • C Concepts: Function definition, conditionals, character output
  • Logic: Checks if input is negative, prints 'N' or 'P' accordingly

• c00/ex05/ft_print_comb.c

  • Type: C source file
  • Purpose: Print all unique combinations of three different digits in ascending order
  • C Concepts: Function definition, nested loops, conditionals, character output
  • Logic: Uses three nested loops to generate combinations, prints with commas and spaces

• c00/ex06/ft_print_comb2.c

  • Type: C source file
  • Purpose: Print all unique combinations of two two-digit numbers
  • C Concepts: Function definition, nested loops, character output, formatting
  • Logic: Uses nested loops to generate and print all pairs of two-digit numbers, formatted with spaces and commas

• c00/ex07/ft_putnbr.c

  • Type: C source file
  • Purpose: Print an integer to standard output
  • C Concepts: Function definition, recursion, integer to character conversion, output
  • Logic: (Implementation missing in provided code, but typically recursively prints each digit)

• c00/ex08/ft_print_combn.c

  • Type: C source file
  • Purpose: Print all combinations of n different digits in ascending order
  • C Concepts: Function definition, arrays, loops, recursion, output formatting
  • Logic: (Implementation incomplete in provided code, but typically generates all combinations recursively)

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• c01/ex00/ft_ft.c

  • Type: C source file
  • Purpose: Set the value pointed to by an integer pointer to 42
  • C Concepts: Pointers, dereferencing, assignment
  • Logic: *nbr = 42;

• c01/ex01/ft_ultimate_ft.c

  • Type: C source file
  • Purpose: Set the value pointed to by a pointer to a pointer to ... to an int (9 levels) to 42
  • C Concepts: Multiple levels of pointers, dereferencing, assignment
  • Logic: *********nbr = 42;

• c01/ex02/ft_swap.c

  • Type: C source file
  • Purpose: Swap the values of two integers using pointers
  • C Concepts: Pointers, dereferencing, assignment, temporary variable
  • Logic: Uses a temporary variable to swap *a and *b

• c01/ex03/ft_div_mod.c

  • Type: C source file
  • Purpose: Store the division and modulo of two integers in two pointers
  • C Concepts: Pointers, dereferencing, arithmetic operations
  • Logic: *div = a / b; *mod = a % b;

• c01/ex04/ft_ultimate_div_mod.c

  • Type: C source file
  • Purpose: Update two integers via pointers to their division and modulo
  • C Concepts: Pointers, dereferencing, arithmetic operations
  • Logic: (Implementation incomplete, but typically sets *a = *a / *b; *b = *a % *b;)

• c01/ex05/ft_putstr.c

  • Type: C source file
  • Purpose: Print a string to standard output
  • C Concepts: Pointers, character arrays, loops, output
  • Logic: Loops through the string, printing each character with write

• c01/ex06/ft_strlen.c

  • Type: C source file
  • Purpose: Return the length of a string
  • C Concepts: Pointers, character arrays, loops, counting
  • Logic: Loops through the string, counting characters until \0

• c01/ex07/ft_rev_int_tab.c

  • Type: C source file
  • Purpose: Reverse the contents of an integer array
  • C Concepts: Arrays, pointers, loops, swapping
  • Logic: Swaps elements from both ends moving toward the center

• c01/ex08/ft_sort_int_tab.c

  • Type: C source file
  • Purpose: Sort an integer array in ascending order
  • C Concepts: Arrays, pointers, loops, sorting algorithms
  • Logic: Uses a simple bubble sort to sort the array in place

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• c02/ex00/ft_strcpy.c

  • Type: C source file
  • Purpose: Copy a string from src to dest
  • C Concepts: Pointers, character arrays, loops, string manipulation
  • Logic: Loops through src, copying each character to dest until \0, then returns dest

• c02/ex01/ft_strncpy.c

  • Type: C source file
  • Purpose: Copy up to n characters from src to dest
  • C Concepts: Pointers, character arrays, loops, string manipulation, length-limited copy
  • Logic: Loops through src up to n characters, copying to dest, then returns dest

• c02/ex02/ft_str_is_alpha.c

  • Type: C source file
  • Purpose: Check if a string contains only alphabetic characters
  • C Concepts: Pointers, character arrays, loops, conditionals, ASCII value checks
  • Logic: Loops through str, returns 1 if all characters are alphabetic, 0 otherwise

• c02/ex03/ft_str_is_numeric.c

  • Type: C source file
  • Purpose: Check if a string contains only numeric characters
  • C Concepts: Pointers, character arrays, loops, conditionals, ASCII value checks
  • Logic: Loops through str, returns 1 if all characters are digits, 0 otherwise

• c02/ex04/ft_str_is_lowercase.c

  • Type: C source file
  • Purpose: Check if a string contains only lowercase letters
  • C Concepts: Pointers, character arrays, loops, conditionals, ASCII value checks
  • Logic: Loops through str, returns 1 if all characters are lowercase, 0 otherwise

• c02/ex05/ft_str_is_uppercase.c

  • Type: C source file
  • Purpose: Check if a string contains only uppercase letters
  • C Concepts: Pointers, character arrays, loops, conditionals, ASCII value checks
  • Logic: Loops through str, returns 1 if all characters are uppercase, 0 otherwise

• c02/ex06/ft_str_is_printable.c

  • Type: C source file
  • Purpose: Check if a string contains only printable characters
  • C Concepts: Pointers, character arrays, loops, conditionals, ASCII value checks
  • Logic: Loops through str, returns 1 if all characters are printable, 0 otherwise

• c02/ex07/ft_strupcase.c

  • Type: C source file
  • Purpose: Convert all lowercase letters in a string to uppercase
  • C Concepts: Pointers, character arrays, loops, ASCII value manipulation
  • Logic: Loops through str, subtracts 32 from lowercase letters to convert to uppercase

• c02/ex08/ft_strlowcase.c

  • Type: C source file
  • Purpose: Convert all uppercase letters in a string to lowercase
  • C Concepts: Pointers, character arrays, loops, ASCII value manipulation
  • Logic: Loops through str, adds 32 to uppercase letters to convert to lowercase

• c02/ex09/ft_strcapitalize.c

  • Type: C source file
  • Purpose: Capitalize the first letter of each word in a string
  • C Concepts: Pointers, character arrays, loops, ASCII value manipulation, word boundary detection
  • Logic: Loops through str, capitalizes first letter after space or at start

• c02/ex10/ft_strlcpy.c

  • Type: C source file
  • Purpose: Copy up to size-1 characters from src to dest, null-terminating the result
  • C Concepts: Pointers, character arrays, loops, string manipulation, buffer size management
  • Logic: Loops through src up to size-1 characters, copies to dest, null-terminates

• c02/ex11/ft_putstr_non_printable.c

  • Type: C source file
  • Purpose: Print a string, replacing non-printable characters with their hexadecimal representation
  • C Concepts: Pointers, character arrays, loops, ASCII value checks, hexadecimal conversion, output formatting
  • Logic: Loops through str, prints printable characters, prints hex for non-printable

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• c03/ex00/ft_strcmp.c
  • Type: C source file
  • Purpose: Compare two strings lexicographically
  • C Concepts: Pointers, character arrays, loops, ASCII value comparison
  • Logic: Loops through both strings, returns difference at first mismatch or 0 if equal

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This repository is a comprehensive record of my journey through the 42 Seoul kernel and shell curriculum, with hands-on practice in shell scripting, C programming, and system-level concepts. Each file is commented to explain its purpose and the concepts it demonstrates.