Linux Commands and File System Management

Posted on Jan 24, 2025 in Business Sciences

Essential Linux Commands and File Management

ULI101: Introduction to UNIX/Linux and the Internet – Week 1, Lesson 2

Basic Linux Command Structure

• Command Format: command argument1 argument2 ...
  • Examples:
    • pwd: Display current directory.
    • date: Show current date and time.
    • ls: List files in the current directory.
    • ls /etc: List files in /etc directory.
    • ls -l: Detailed file listing in the current directory.
    • ls -l /etc: Detailed file listing in /etc directory.

Getting Help with Commands

• man command: View manual for any Linux command.
  • Example: man ls
• Search Help:
  • man -k <keyword>: Search for commands related to a keyword.
  • Example: man -k copy

Man Command Navigation Shortcuts

• ENTER: Move down one line.
• SPACEBAR: Move one screen down.
• Ctrl + b: Move one screen up.
• /pattern: Search for a pattern.
• q: Quit the man page.

General Linux Commands

• pwd: Display current directory.
• cd <dir-pathname>: Change directory.
• ls -l / -a / -R / -d<dir-pathname>: List directory contents.
• cal <month> <year>: Display calendar.
• date: Show date and time.
• who: List users logged in.
• whoami: Display your username.
• clear: Clear the screen.
• passwd <username>: Change password.

Command Line Editing Shortcuts

• Ctrl + l: Clear screen.
• Ctrl + u: Clear command line.
• Up/Down Arrow: Scroll through command history.
• Backspace: Delete character before the cursor.
• Ctrl + w: Delete word before the cursor.
• Ctrl + a: Move to the beginning of the command line.
• Ctrl + e: Move to the end of the command line.
• Alt + f / Alt + b: Move forward/backward one word.

ULI101: Introduction to UNIX/Linux and the Internet – Week 2, Lesson 1

Unix/Linux File Management Concepts

• Purpose of Directories:

  • Organize files (e.g., text, images, documents) within your account.
  • Directories can contain sub-directories for better organization.

• Unix/Linux File System:

  • Hierarchical structure starting from the “root directory” (/).
  • No drive letters like in Windows (e.g., C:, D:).
  • Use the tree command to display the directory tree diagram.

• Directory Pathnames:

  • Pathnames specify the location of files within the file system.
  • Use slash (/) as the delimiting character.
  • Example: /home/your-seneca-id

• Common Unix/Linux Directories:

  • /: Root directory (ancestor to all directories).
  • /home: Stores users’ home directories.
  • /home/username: Specific user’s home directory.
  • /bin, /usr/bin: Common system binaries (commands).
  • /usr/sbin: Utilities for system administration.
  • /etc: System administration files (e.g., passwd).
  • /var: Dynamic files (logs, mail files).
  • /tmp, /var/tmp: Temporary files.
  • /dev: Device driver files (terminals, printers).

• Filename Rules:

  • Case sensitive: Use lowercase letters.
  • Consistent naming schemes.
  • Use meaningful, short, and descriptive names.
  • Avoid spaces in directory names; use periods, hyphens, or underscores.
  • Avoid non-alphanumeric characters as they may have special meanings.

Managing Directories

• Common Commands:

  • mkdir -p: Create directories (with parent directories if needed).
  • rmdir: Remove empty directories.
  • rm -r -i: Remove directories and their contents with confirmation.
  • ls -l -d -R, tree: List directory contents or display directory structure.
  • cp -R: Copy directory and its contents.
  • mv: Move directory and its contents.

• Determining File Types:

  • Use ls -l to list directory contents with details.
  • The first character indicates file type:
    • d: Directory
    • -: Regular file
    • b, c: Device file

• Hidden Files:

  • Files starting with a period (.) are hidden.
  • ls without arguments doesn’t show hidden files.
  • ls -a: Show all files, including hidden files.
  • ls -A: Show all files, excluding current (.) and parent (..) directories.