How to Use the Nushell Command (with Examples)

Nushell, often referred to simply as “nu,” is a modern command-line shell designed to bring new perspectives and functionality to traditional shell usage. It offers a structured data approach, where outputs are handled more like database tables, making them easier to manipulate and query. Nushell is particularly useful for developers and system administrators looking for more versatility and enhanced data manipulation capabilities in their command-line workflows.

Start an Interactive Shell Session

Code:

nu

Motivation:

Starting an interactive shell session with Nushell is akin to launching any other shell like Bash or Zsh. This use case is foundational because it allows users to enter into a Nushell environment where they can execute commands in an interactive and exploratory manner. It’s ideal for instances when users want to try out Nushell’s unique features, perform real-time data manipulations, or simply manage their files and systems efficiently within a structured shell environment.

Explanation:

The command nu without any additional arguments starts Nushell in its interactive mode. This mode waits for user input, executing commands as they are typed, which is perfect for exploratory programming or for moment-to-moment system administration tasks.

Example Output:

Welcome to Nushell!
~> _

Execute Specific Commands

Code:

nu --commands "echo 'nu is executed'"

Motivation:

Executing specific commands directly from the shell is a necessity when users want quick feedback or need to batch process data without entering an interactive session. This use case is particularly beneficial for developers who want to quickly test snippets of Nushell scripting or automate small tasks directly from the command line or a script.

Explanation:

• nu is the command that initiates Nushell.
• --commands specifies that what follows is a string of commands rather than a script file. This option is ideal for short, one-off commands.
• "echo 'nu is executed'" is a simple command that outputs the text string ’nu is executed’, confirming that the command runs successfully.

Example Output:

nu is executed

Execute a Specific Script

Code:

nu path/to/script.nu

Motivation:

Running a specific script allows users to automate complex tasks that have been predefined in a Nushell script file. This is crucial for recurring operations that require more than a simple one-liner, such as data processing pipelines, automation scripts, or configuration changes across systems.

Explanation:

• nu launches the Nushell interpreter.
• path/to/script.nu is the path to the Nushell script that should be executed. This script can include any sequence of valid Nushell commands, enabling complex operations to be performed in a single run.

Example Output:

Assuming script.nu contains echo 'Hello from Nushell script!', the output would be:

Hello from Nushell script!

Execute a Specific Script with Logging

Code:

nu --log-level info path/to/script.nu

Motivation:

Executing scripts with logging is indispensable for debugging and monitoring complex scripts. It provides visibility into the script’s operation, helping users catch errors, understand flow, and see detailed execution information as needed.

Explanation:

• nu starts the Nushell process.
• --log-level info sets the verbosity of log messages. The levels available are error, warn, info, debug, and trace, which correspond to increasing levels of detail in logging. The info level provides basic information useful for understanding script progress and outcomes.
• path/to/script.nu is the file path of the script to be executed, which may include logging statements to provide output at various verbosity levels.

Example Output:

Assuming script.nu contains logging commands, the output might include:

info: Starting script execution...
Hello from Nushell script!
info: Completed script successfully.

Conclusion

Nushell provides a modern shell experience with its structured data strategies and built-in commands designed to make the command-line experience more intuitive and powerful. These examples demonstrate how Nushell can be used interactively, to execute commands directly, run scripts, and track their execution with logging. As users become familiar with its features, Nushell can significantly enhance productivity in command-line tasks.