[Day 1] 6. User Interfacing

User Interfacing

In an operating system, there are two main types of interfaces through which users can interact with the system:

1. GUI (Graphical User Interface):

   • Interaction through graphical elements like windows, icons, and buttons.
   • More user-friendly, typically used by casual users.

2. CLI (Command-Line Interface):

   • Interaction through text-based commands.
   • Used by advanced users and administrators for greater control and flexibility.

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Shell

The shell serves as an intermediary between the user and the operating system. It is also referred to as a command interpreter because it interprets the commands entered by the user and then passes them to the OS for execution.

• After the OS executes the command, the shell displays the output to the user.

Common Shells in Linux

• bash (Bourne Again Shell):
  • The default shell in most Linux distributions.
  • It's an advanced version of the original sh (the Unix shell).
• Terminal:
  • A GUI application that gives access to the CLI.
  • When using the terminal, you are essentially interacting with the bash shell by default in most Linux systems.

Extra: GNU Project and Free Software

• GNU stands for GNU’s Not Unix. It was a project aimed at creating a Unix-like operating system that was free and open source.
  • The GNU project promoted the development of free software that anyone could use, modify, and share.
  • GPL (General Public License): A key aspect of GNU's philosophy, under which software is made available to the public free of cost. Any software licensed under GPL must remain free and open.

Linux Distributions

• All Linux distributions (distros) are community-driven projects. This means that developers from around the world contribute to their development.
• GNU/Linux is often used to refer to Linux systems because many parts of the operating system are built using GNU tools and software.