A command line shell is a command-line interface that allows users to interact with a computer by entering commands as text input. The shell reads the commands, processes them, and executes them, displaying the results on the command line or saving them to a file.
There are many different command line shells available for Unix-like operating systems, such as Bash, Zsh, and Ksh, and for Microsoft Windows, such as cmd and PowerShell. Each shell has its own syntax for entering commands and its own set of built-in commands and features.
To use a command line shell, you can open a terminal window or command prompt and type in commands at the command prompt. The command prompt is the symbol or text that indicates that the shell is ready to accept input.
Commands can be entered on a single line or multiple lines, depending on the shell and the command. Most shells allow you to use the Enter key to start a new line and the Up and Down arrow keys to browse through previously entered commands.
Commands can include options, which are flags or arguments that modify the behavior of the command. Options are typically preceded by a - or -- character and are followed by a value or a set of values.
To get help with a command or learn more about its options and usage, you can use the --help or -h option. For example, to get help with the ls command, you can use the following command:
ls --help
This will display a brief description of the ls command and its options.
To learn more about command line shells and how to use them, you can consult the documentation for your specific shell and operating system. There are also many online resources and tutorials available that can help you get started with command line shells.