1. File System Overview

1.1 What Is a File System?

• Definition: A file system is a hierarchical structure that organizes how files and directories (folders) are stored and managed on a computer.
• Components:
  • File: A unit of storage that holds data (text, images, executables, etc.).
  • Directory: A container (or catalogue) that holds files and/or other directories, forming a tree-like (arborescent) structure.

1.2 File and Directory Naming Rules

• File Names in Linux:

  • Can be up to 255 characters.

  • Some characters should be avoided as they may cause issues:

    *  &  ;  (  )  <space>  ~  \\  |  `  ?  - (if used as the first character)
    
    

• Examples of Problematic File Names:

  • nom_fichier* → The asterisk `` can be interpreted as a wildcard.
  • iir(s5) → Parentheses can interfere with command interpretation.
  • iir&info → The ampersand & has special meaning in the shell.
  • resultat juin 2023.xls → Spaces in file names can cause issues unless escaped or quoted.
  • file.txt → A leading hyphen might be confused with an option flag.

2. Linux File System Hierarchy

2.1 Single Root vs. Multiple Roots

• Linux:
  • Uses a single root directory represented by /.
• Windows:
  • Uses multiple roots (e.g., C:, D:, etc.).

2.2 Key Directories in Linux

• / (Root): The top-level directory containing all other directories and files.
• /root: The home directory for the root (administrator) user.
• /bin: Contains essential executables available to all users (e.g., ls, rm, cp, chmod).
• /dev: Contains device files that act as entry points to hardware devices.
• /home: Contains personal directories for regular users (e.g., /home/mehdi).
• /tmp: Holds temporary files.