Basics & History of Linux

Source: Dev.to

UNIX Origins

• 1964 – Bell Laboratories (New Jersey) began the UNIX project.
• 1969 – The original project was withdrawn, but Dennis Ritchie and Ken Thompson continued their work, creating an operating system originally called UNICS (Uniplexed Information & Computing Services).
• 1975 – UNIX Version 6 (v6) was released, gaining rapid global attention and popularity.

UNIX‑based Operating Systems

• IBM – AIX
• Sun Microsystems – Solaris
• Apple – macOS
• HP – HP‑UX

Creation of Linux

In 1991, Linus Torvalds (software engineer) wrote the Linux kernel from scratch, drawing inspiration from UNIX. Around the same time, Andrew S. Tanenbaum created MINIX, a teaching operating system. Linux is free and open‑source, offering multitasking and multi‑user capabilities.

Linux Distributions

• RHEL – Red Hat Enterprise Linux (commercial support)
• Fedora – Community‑driven, upstream of RHEL
• Debian – Stable, community‑maintained base
• Ubuntu – Widely adopted desktop and server distro
• CentOS – Binary‑compatible with RHEL, focused on stability
• Amazon Linux – Optimized for AWS environments
• Kali Linux – Specialized for penetration testing and security research

Ways to Operate an Operating System

1. CLI (Command Line Interface) – Commands are typed to instruct the computer.
2. GUI (Graphical User Interface) – Visual elements (windows, icons) are used to interact with the system.

Linux: Kernel vs. Operating System

• Linux is the kernel.
• Combined with GNU utilities and other software, it forms a complete operating system.

Linux (kernel) + GNU → Operating System

Linux is not a UNIX derivative; it was written from scratch. A Linux distribution bundles the kernel with a collection of software to provide a functional OS.

Advantages / Features of Linux

• Open‑source
• Secure
• Simplified updates for all installed software
• Lightweight
• Supports multi‑user and multitasking
• Wide variety of distributions (e.g., Red Hat, Debian, Fedora)

Linux File System Hierarchy

• /home – Home directories for regular users
• /root – Home directory for the root user
• /boot – Bootloader files and kernel images
• /etc – System configuration files
• /usr – Default location for installed software
• /bin – Essential command binaries for all users
• /sbin – System binaries, primarily for the root user
• /opt – Optional third‑party application packages
• /dev – Device files (terminals, USB devices, etc.)