Embedded Learning (Linux Module)

Apr 21. 2026

Embedded Development Software Layers #

Embedded systems are divided into application layer, kernel layer, and hardware layer.

Development Tech Stack #

Reserve Knowledge: Linux System Basics

• Main Content:
  1. Linux File System Structure
  2. Commonly Used Shell System Commands
  3. User and Permission Management
  4. VIM Text Editing
  5. Shared Environment Setup

Installation Issues #

• Issues encountered when installing virtual machine image ISO on Mac version

According to the server image version address: https://old-releases.ubuntu.com/releases/ Install the latest version, there will be no screen adaptation issues.

First install the server version of Ubuntu, then use sudo apt install ubuntu-desktop for the desktop version, after execution, use sudo reboot to restart.

Mac ARM version cannot use VMware 3D hardware acceleration.

Linux Basics #

File Structure #

Linux system file structure:

File Command Instructions #

Quick Reference: https://wangchujiang.com/reference/docs/linux-command.html

1. ls -a Show all files
2. ls -l Show file details File types: d directory l link (shortcut) s socket link b block device i index p pipe c character device

3. cd - Go back to previous directory
4. mkdir -p Create directory recursively
5. touch Create file modify file time create multiple files using {} separated by , {1…10}
6. rm -rf Delete file -i ask before delete rmdir -p Delete directory
7. cp -R Copy directory -r copy -f force overwrite -i ask

Here is a quick reference table for commonly used file operations, text processing, and Vim editor commands in Linux systems.

File Operations and Text Processing #

1. File Viewing (Read) #

Used to read and browse file contents.

2. File Writing (Write) #

Quickly generate or append text content.

3. File Search (Search) #

Locate files in the system or filter content.

Vim Editor Commands #

Core Modes #

• Command Mode (Command): Default state after starting Vim, used for executing operation commands.
• Insert Mode (Insert): Enter by typing i, a, o etc., used for inputting text.
• Last Line Mode (Last Line): Enter by typing :, used for save, exit, or find/replace.

1. Cursor Movement and Jumping #

2. Editing Operations (Command Mode) #

3. Search and Replace (Last Line Mode) #

4. Save and Exit (Last Line Mode) #

Other Commands #

These commands are usually entered in Vim’s Command Mode (after pressing Esc).

User and Permission Management #

1. User Switching #

Switch between different user identities.

• sudo -i: Switch to root user (requires current user to have sudo permissions).
• exit: Exit current user, return to previous logged-in user.
• su -: Switch user (usually followed by username, like su - username, - loads target user’s environment variables).

2. User Management #

Manage system login users.

3. Password Management #

Use passwd command to manage user passwords.

4. User Group Management #

Manage user group memberships.

• groupadd: Add a new user group.
• groupdel: Delete an existing user group.
• groups: View all groups a user belongs to.
• groupmod: Modify user group attributes (such as group name -n or group ID -g).
• chgrp: Modify the group ownership of a file or directory. -R recursive modification
• chown: Modify the user ownership of a file or directory. chown -R [username][:groupname] [filename]
• chmod: Modify file or directory permissions. -R recursive modification chmod -R [permissions] [filename]

Text description: agu; numeric description, 4210

Note: For newly added users, re-authorization is needed. For sudo authorization, add to configuration file ./etc/sudoers.d/username Use visudo command for user privilege authorization.