magic-commands.md

Magic Commands

A magic command is a scriptable shortcut to a more complex behavior. The magic command concept is familiar to Jupyter users. With a slight change in syntax to accommodate the .NET languages, they're also available in .NET Interactive.

Magic commands must always occur at the beginning of a line and are prefixed with either #! or, less commonly, #. The latter occurs only when unifying behaviors with language-specific compiler directives such as #r, a compiler directive that's implemented in both C# and F# script. Another difference from Jupyter's magic commands is that in .NET Interactive there is no distinction between a "cell magic" and a "line magic".

Here's an example using the #!time magic command:

Magic commands use a command line-style syntax, including options and arguments similar to a command line tool. For every magic command, you can get help using -h:

The following is a list of magic commands supported by .NET Interactive:

.NET Kernel

The following magic commands are available globally.

Command	Behavior
#!csharp (also: #!c#, #!C#)	Indicates that the code that follows is C#. Specifically, it is the C# scripting dialect.
#!fsharp (also: #!f#, #!F#)	Indicates that the code that follows is F#.
#!pwsh (also: #!powershell)	Indicates that the code that follows is PowerShell.
#!javascript (also: #!js)	Indicates that the code that follows is JavaScript, to be executed in the browser.
#!html	Indicates that the code that follows is HTML, which can then be directly rendered in the browser.
#!lsmagic	Lists the available magic commands, including those that might have been installed via an extension.
#!markdown	Indicates that the code that follows is Markdown, which can then be directly rendered as HTML in the browser.
#!log	Enables logging for the session. Once it has been run, detailed log information from .NET Interactive will be published along with other code outputs.
#!about	Displays information about the current version of .NET Interactive:
#!time	Measures the execution time of the code submission.
#!value	Stores a value (from entered text, a file, or a URL), which can be accessed using #!share.

C# Kernel

The following magic commands are available within a C# language context.

Command	Behavior
#i	Adds a NuGet source to the session. Subsequent #r nuget commands will include the specified source when resolving packages.
#r	In C# Interactive, the #r directive adds a reference to a specified assembly, e.g. #r "/path/to/a.dll". In .NET Interactive, this capability has been expanded to provide the ability to reference NuGet packages. You cannot reference two different versions of the same package. If you try to do so, you'll receive an error:
#!share	Shares a variable from another specified subkernel (including one stored using #!value).
#!who	Displays the names of the top-level variables within the C# subkernel.
#!whos	Displays the top-level variables within the C# subkernel, including their name, type, and value.

F# Kernel

The following magic commands are available within an F# language context.

Command	Behavior
#i	Adds a NuGet source to the session. Subsequent #r nuget commands will include the specified source when resolving packages.
#r	In F# Interactive, the #r directive adds a reference to a specified assembly, e.g. #r "/path/to/a.dll". In F# 5, which is used by .NET Interactive, this capability has been expanded to provide the ability to reference NuGet packages. You cannot reference two different versions of the same package. If you try to do so, you'll receive an error:
#!share	Shares a variable from another specified subkernel (including one stored using #!value).
#!who	Displays the names of the top-level variables within the F# subkernel.
#!whos	Displays the top-level variables within the F# subkernel, including their name, type, and value.

Extensibility

Magic commands can be added dynamically to .NET Interactive's kernels, either at the global level or to individual language-specific subkernels. You can learn more about how to do this here.