Bayu Setiawan
Linux Shells: Understanding the Basics of Command Line Interfaces

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Linux Shells: Understanding the Basics of Command Line Interfaces

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Bayu Setiawan
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2 min read

The command line interface (CLI) is an essential part of Linux and other Unix-like operating systems. The CLI provides a text-based interface to interact with the system and execute commands.

Here are the basics of Linux command line interfaces:

The Shell

The shell is a program that provides the command line interface. It takes commands from the user and executes them.

Some of the most popular shells in Linux are:

  • Bash - The default shell in most Linux distributions

  • Zsh - An advanced shell with many features

  • Fish - An interactive shell with tab-completion and syntax highlighting

When you open a terminal, you are greeted by a shell prompt. It shows the current user, hostname, and working directory.

For example:

john@linuxbox:/home/john$

After the prompt, you can type commands and press Enter to execute them.

Command Syntax

Most commands follow this basic syntax:

command [options] [arguments]

  • command - The name of the command to execute

  • [options] - Optional flags to modify the behavior of the command

  • [arguments] - Optional arguments passed to the command

For example:

ls -l /home

Here:

  • ls is the command

  • -l is the option for a long listing

  • /home is the argument, the directory to list

Some common options are:

  • -a - Show all files including hidden ones

  • -l - Long listing format

  • -h - Human readable sizes

Basic Commands

Some of the most basic and useful commands are:

  • ls - List directory contents

  • cd - Change directory

  • pwd - Print working directory

  • cat - Concatenate and print files

  • head - Output the first part of a file

  • tail - Output the last part of a file

  • cp - Copy files and directories

  • mv - Move (rename) files and directories

  • rm - Remove files and directories

You can also use pipes (|) and redirections (> and >>) to combine commands.

So in summary, the command line interface provides a powerful and flexible text-based way to interact with a Linux system. Understanding the basics of shells, commands, and their syntax will allow you to navigate and manipulate files, directories, and more on the command line.

Hope this helps explain the basics of Linux command line interfaces! Let me know if you have any other questions.

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