Frequently Asked Questions

Where can I learn PowerShell's syntax?

What is PowerShell?
Discover PowerShell
PowerShell 101
PowerShell learning resources

What are the best practices and styles?

The PoshCode unofficial guide is our reference.

What are PowerShell's scoping rules?

Variables are created in your current scope unless explicitly indicated.
Variables are visible in a child scope unless explicitly indicated.
Variables created in a child scope are not visible to a parent unless explicitly indicated.
Variables may be placed explicitly in a scope.

Things that create a scope

about_Functions_Advanced
about Operators - Call operator (& { })
about Scopes

Things that operate in the current scope

about Operators - Dot source operator (. { })
about Language Keywords (if .. else, for, switch, etc.)

Why didn't an error throw an exception?

Error handling in PowerShell is unique, as not all errors result in catchable exceptions by default. Setting $ErrorActionPreference = 'Stop' will likely do what you want; that is, cause non-terminating errors instead of terminating. Read the GitHub issue for more information.

Where do I get the PowerShell Core SDK package?

The SDK NuGet package Microsoft.PowerShell.SDK is provided for developers to write C# code targeting PowerShell. PowerShell NuGet packages are published to Microsoft.PowerShell.SDK on NuGet.org.

To use the Microsoft.PowerShell.SDK NuGet package, declare PackageReference tags in your .csproj file as follows:

<ItemGroup>
  <PackageReference Include="Microsoft.PowerShell.SDK" Version="7.3.5" />
  <PackageReference Include="Microsoft.PowerShell.Commands.Diagnostics" Version="7.3.5" />
  <PackageReference Include="Microsoft.WSMan.Management" Version="7.3.5"/>
</ItemGroup>

Why did my build fail?

There are few common issues with the build. The easiest way to resolve most issues with the build is to run Start-PSBuild -Clean.

Dependency changed

If package dependencies were changed in any project.json, you need to manually run dotnet restore to update your local dependency graphs. Start-PSBuild -Restore can automatically do this.

Resource changed

Start-PSBuild automatically calls Start-ResGen on the very first run. On subsequent runs, you may need to explicitly use Start-PSBuild -ResGen command.

Try it, when you see compilation error about *strings.

More details about resource.

TypeGen

Similar to -ResGen parameter, there is -TypeGen parameter that triggers regeneration of type catalog.

Why did `Start-PSBuild` tell me to update `dotnet`?

We depend on the latest version of the .NET CLI, as we use the output of dotnet --info to determine the current runtime identifier. Without this information, our build function can't know where dotnet is going to place the build artifacts.

You can automatically install this using Start-PSBootstrap. However, you must first manually uninstall other versions of the CLI.

If you have installed by using any of the following means:

MSI
exe
apt-get
pkg

You must manually uninstall it.

Additionally, if you've just unzipped their binary drops (or used their obtain scripts, which do essentially the same thing), you must manually delete the folder, as the .NET CLI team re-engineered how their binaries are setup, such that new packages' binaries get stomped on by old packages' binaries.

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