Ubuntuとは

Ubuntu Beginner Tutorial – Summary

1. What is Ubuntu?

• Ubuntu is a free, open-source OS based on the Linux kernel.
• Designed for ease of use, even for beginners.
• Released every 6 months; LTS (Long-Term Support) versions every 2 years.

2. Linux Kernel and OS Structure

• The Linux kernel is the core component of the OS, written in C.
• The OS manages all hardware; user programs cannot access devices directly.
• Kernel modules allow adding/removing features without rebooting.

3. Boot Process and Bootloaders

• Boot sequence: BIOS → bootloader (e.g., GRUB) → kernel → user space.
• Multi-boot systems (dual, triple boot) are supported.

4. GUI and CUI

• Ubuntu uses both GUI (e.g., LightDM) and CUI (e.g., virtual console).
• If the GUI fails, users can operate Ubuntu via the command-line interface (CUI).

5. Terminal Usage

• The terminal allows users to perform file operations, run scripts, and automate tasks.
• Environment variables (e.g., PATH) and shell (e.g., Bash) are essential components.
• Commands can be combined with pipes and arguments.

6. Files and Permissions

• File system is hierarchical; the top directory is the root (/).
• File permissions include read/write/execute for owner, group, and others.
• Represented as strings or octal numbers (e.g., 777).

7. Software Installation and Management

• Software is typically managed with the apt package manager.
• Installation methods include package manager, binaries, or building from source.
• Dependency management and conflicts are important to understand.

8. Processes and Job Control

• Processes are structured in a parent-child hierarchy starting from init (systemd).
• Jobs represent process groups and can run in foreground or background.
• Signals (e.g., Ctrl+C, kill) are used to control process states.

9. File Systems and Mounting

• Everything is treated as a file in Linux, including devices.
• Devices are mounted to directories (e.g., /mnt) and can be auto-mounted via fstab.

10. SSH and Remote Access

• SSH allows secure remote login using public-key authentication.
• After connecting via ssh, all terminal commands affect the remote server.

11. Final Notes

• Troubleshooting often requires internet research; English search yields better results.
• This tutorial is an overview; detailed follow-up videos will cover specific topics.

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