Lesson 1.3: Kernel, shell and terminal
The difference between the terminal, the shell and the kernel; CLI vs GUI; reading the prompt; what happens between typing a command and seeing its output. Lab: whoami, hostname, $SHELL, ps and /etc/shells.
15 min
You will learn to
- Tell the terminal, the shell and the kernel apart
- Explain CLI vs GUI and why servers use the CLI
- Read every part of a bash prompt
- Find out which shell you are using and which shells are installed
Key terms
- Graphical user interface (GUI)
- Using the computer through windows, icons and a mouse.
- Command-line interface (CLI)
- Using the computer by typing text commands and reading text answers.
- Terminal (terminal emulator)
- The window program that shows text and sends what you type. It doesn't understand commands itself; it only carries text back and forth.
- Console
- Originally the terminal physically attached to the machine itself; today often used to mean any terminal.
- Shell
- The program that reads the commands you type, understands them, starts the right programs and shows you their results. It sits between you and the kernel, like a shell around a nut.
- Bash
- The most common shell on Linux and the default on Ubuntu.
- Prompt
- The text the shell prints when it is ready for your next command.
- Command
- A word that names a program (or a shell feature) to run, optionally followed by options and arguments, executed with Enter.
- Process
- A program while it is running. The same program can run as several processes at once.
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