linux

open-source operating system

highly flexible: users can customize everything
secure: less prone to malware
distributions: different packaged versions of linux
- 3 main distributions:
  - debian
    - ubuntu
  - fedora
  - arch
- each distribution includes various software components:
  - system libraries
  - applications
  - package manager (e.g. apt, dnf, pacman)
kernel
- the core of the OS
- one of the first programs loaded during startup
- acts as a bridge between hardware and user-level applications, controlling the allocation of system resources
- responsible for:
  - hardware abstraction
  - process scheduling and management
  - memory allocation and management
  - file system operations (read/write)
  - device I/O operations
  - system calls handling
  - interrupt handling
  - inter-process communication (IPC)
GNU system utilities
- cp, mv, rm, mkdir, grep, sed, awk, sort, uniq, chmod, ssh, etc
GNU libraries
- glibc (GNU Clibrary)
  - string manipulation
  - memory management (malloc, free)
  - math operations
  - file I/O
  - networking
- libstdc++ (GNU standard C++ library)
- libm (GNU math library)
- libutil (GNU utility library)
- librt (GNU real-time library)
- etc

linux directory structure