LWM-Linux/02 - Basic System Operations/Using Linux Terminal (Shell BASH).md

Using the Linux Terminal (BASH Shell)

1. Opening the Terminal:

• You can open the terminal in various ways:
  • Shortcut: Press Ctrl + Alt + T.
  • Application Menu: Search for "Terminal" in your applications.
  • Command: Use the gnome-terminal command.

2. Basic Navigation:

• pwd: Print working directory
• ls: List files and directories
• cd: Change directory
• mkdir: Create a new directory
• rmdir: Remove an empty directory
• touch: Create an empty file

3. File Operations:

• cp: Copy files or directories
• mv: Move or rename files/directories
• rm: Remove files or directories
• cat: Display file contents
• less: View file contents page by page
• head/tail: View beginning/end of a file

4. Text Editing:

• nano: Simple text editor
• vim: Advanced text editor
• emacs: Another advanced text editor

5. File Permissions:

• chmod: Change file permissions
• chown: Change file owner
• chgrp: Change group ownership

6. Process Management:

• ps: List running processes
• top: Dynamic view of system processes
• kill: Terminate a process
• fg/bg: Bring process to foreground/background

7. System Information:

• uname: Display system information
• df: Show disk usage
• du: Display directory space usage
• free: Show memory usage

8. Network Commands:

• ifconfig: Configure network interfaces
• ping: Test network connectivity
• ssh: Secure shell for remote access
• scp: Securely copy files between hosts

9. Package Management:

• apt-get (Debian/Ubuntu): Install, update, remove packages
• yum (CentOS/Fedora): Similar to apt-get
• dnf (Fedora): Next-generation package manager

10. File Compression:

• tar: Archive files
• gzip/gunzip: Compress/decompress files
• zip/unzip: Create/extract zip archives

11. Text Processing:

- grep: Search for patterns in files
- sed: Stream editor for text manipulation
- awk: Pattern scanning and text processing

12. Redirection and Pipes:

- >: Redirect output to a file OVERWRITING original file if it exists
- >>: Append output to a file or create a new file.
- <: Read input from a file
- |: Pipe output of one command to another "command chaining"

13. User Management:

- useradd: Add a new user
- userdel: Delete a user
- passwd: Change user password

14. Advanced Commands:

- find: Search for files in a directory hierarchy
- xargs: Build and execute command lines from standard input
- sort: Sort lines of text
- uniq: Report or omit repeated lines

15. Shell Scripting:

- Variables: var_name=value
- Conditionals: if, elif, else
- Loops: for, while
- Functions: function_name() { commands; }

16. Job Control:

- jobs: List active jobs
- &: Run a command in the background
- Ctrl+Z: Suspend a running process
- Ctrl+C: Terminate a running process