PowerShell/docs/FAQ.md

Where can I learn PowerShell's syntax?

SS64.com is a good resource.

What are the best practices and style?

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:

• functions
• call operator (& { })
• script invocations

Things that operate in the current scope:

• source operator (. { })
• statements (if .. else, for, switch, etc.)

Why didn't an error throw an exception?

Error handling in PowerShell is a bit weird, 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 to instead terminate. Read An Introduction To Error Handling in PowerShell for more information.

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 via 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.

Why is my submodule empty?

If a submodule (such as src/Modules/Pester) is empty, that means it is uninitialized. If you've already cloned, you can do this with:

git submodule init
git submodule update

You can verify that the submodules were initialized properly with:

git submodule status

If they're initialized, it will look like this:

 f23641488f8d7bf8630ca3496e61562aa3a64009 src/Modules/Pester (f23641488)
 c99458533a9b4c743ed51537e25989ea55944908 src/libpsl-native/test/googletest (release-1.7.0)
 e6bf85694ae8352d77175c4c7d304946e018808c src/windows-build (monad/cc6afbeb-3/31)

If they're not, there will be minuses in front (and the folders will be empty):

-f23641488f8d7bf8630ca3496e61562aa3a64009 src/Modules/Pester (f23641488)
-c99458533a9b4c743ed51537e25989ea55944908 src/libpsl-native/test/googletest (release-1.7.0)
-e6bf85694ae8352d77175c4c7d304946e018808c src/windows-build (monad/cc6afbeb-3/31)

Please note that the commit hashes for the submodules have likely changed since this FAQ was written.

Why does my submodule say "HEAD detached at" some commit?

When a submodule is first initialized and updated, it is not checked out to a branch, but the very exact commit that the superproject (this PowerShell repository) has recorded for the submodule. This is the intended behavior.

If you want to check out an actual branch, just do so with git checkout <branch>. A submodule is just a Git repository; it just happens to be nested inside another repository.

Please read the Git Book chapter on submodules.