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about_Updatable_Help

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Short description

Describes the updatable help system in PowerShell.

Long description

PowerShell provides several different ways to access the most up-to-date help topics for PowerShell cmdlets and concepts.

The Updatable Help system, introduced in PowerShell 3.0, is designed to assure that you always have the newest help topics on your local computer so that you can read them at the command line. It makes it easy to download and install help files and to update them whenever newer help files become available.

To provide updated help for multiple computers in an enterprise and for computers that don't have access to the internet, Updatable Help lets you download help files to a filesystem directory or file share, and then install the help files from the file share.

In PowerShell 4.0, the HelpInfoUri property is preserved over Windows PowerShell remoting, which allows Save-Help to work for modules that are installed on a remote computer, but aren't necessarily installed on the local computer. You can save a PSModuleInfo object to disk or removable media (such as a USB drive) by running Export-Clixml on a computer that doesn't have internet access, importing the PSModuleInfo object on a computer that does have internet access, and then running Save-Help on the PSModuleInfo object. The saved help can be copied to the remote, disconnected computer by using removable media, and then installed by running Update-Help. These improvements in Save-Help functionality let you install help on computers that are without any kind of network access. For an example of how to use the new Save-Help functionality, see How to update help from a file share in this topic.

Updatable Help also supports online access to the newest help topics and basic help for cmdlets, even when there are no help files on the computer.

PowerShell doesn't come with Help files. You can use the Updatable Help feature to install the help files for all the commands that are included by default in PowerShell and for all Windows modules.

Updatable help cmdlets

  • Update-Help: Downloads the newest help files from the internet or a file share, and installs them on the local computer.

  • Save-Help: Downloads the newest help files from the internet and saves them in a filesystem directory or file share. To install the help files on computers, use Update-Help.

  • Get-Help: Displays help topics at the command line. Gets help from the help files on the computer. Displays auto-generated help for cmdlets and functions that don't have help files. Opens online help topics for cmdlets, functions, scripts, and workflows in your default internet browser.

Auto-generated help: help without help files

If you don't have the help file for a cmdlet, function, or workflow on the computer, the Get-Help cmdlet displays auto-generated help and prompts you to download the help files or read them online.

Auto-generated help includes syntax and aliases, and remarks that explain how to use the Updatable Help cmdlets and to access the online help topics.

For example, the following command gets basic help for the Get-Culture cmdlet. The output shows the Get-Help display when there are no help files on the computer.

Get-Help Get-Culture

NAME
    Get-Culture

SYNTAX
    Get-Culture [<CommonParameters>]

ALIASES
    None

REMARKS
    To get the latest Help content including descriptions and examples
    type: Update-Help.

Help files for modules

The smallest unit of Updatable Help is help for a module. Module help includes help for all the cmdlets, functions, workflows, providers, scripts, and concepts in a module. You can update help for all modules that are installed on the computer, even if they're not imported into the current session.

You can update help for the entire module, but you can't update help for individual cmdlets.

To find the module that contains a particular cmdlet, use the following command format:

(Get-Command <cmdlet-name>).ModuleName

For example, to find the module that contains the Set-ExecutionPolicy cmdlet, type:

(Get-Command Set-ExecutionPolicy).ModuleName

To update help for a particular module, type:

Update-Help -Module <ModuleName>

For example, to update help for the module that contains the Set-ExecutionPolicy cmdlet, type:

Update-Help -Module Microsoft.PowerShell.Security

Permissions for updatable help

To update help for the modules in the directory $pshome/Modules, you must be member of the Administrators group on the computer.

If you aren't a member of the Administrators group, you can't update help for these modules; but if you have internet access, you can view help online.

Updating help for modules in the directory $HOME/Documents/PowerShell/Modules or modules in other subdirectories of the $HOME directory doesn't require special permissions.

The Update-Help and Save-Help cmdlets have a UseDefaultCredentials parameter that provides the explicit credentials of the current user. This parameter is designed for accessing secure internet locations.

The Update-Help and Save-Help cmdlets also have a Credential parameter that allows you to run the command on a remote computer and access a file share on a third computer. The Credential parameter is valid only when you use the SourcePath or LiteralPath parameters of Update-Help and the DestinationPath or LiteralPath parameters of Save-Help.

How to install and update help files

To download and install help files for the first time, or to update the help files on your computer, use the Update-Help cmdlet.

The Update-Help cmdlet does all the hard work for you, including the following tasks.

  • Determines which modules support Updatable Help.
  • Finds the internet location where each module stores its Updatable Help files.
  • Compares the help files for each module on your computer to the newest help files that are available for each module.
  • Downloads the new files from the internet.
  • Unwraps the help file package.
  • Verifies that the files are valid help files.
  • Installs the help files in the language-specific subdirectory of the module directory.

To access the new help topics, use the Get-Help cmdlet. You don't need to restart PowerShell.

To install or update help for all modules on the computer that supports Updatable Help, type:

Update-Help

To update help for particular modules, add the Module parameter of Update-Help. Wildcard characters are permitted in the module name.

For example, to update help for the ServerManager module, type:

Update-Help -Module ServerManager

Without parameters, Update-Help updates help for all modules in the session and for all installed modules that support Updatable Help. To be included, modules must be installed in directories that are listed in the value of the PSModulePath environment variable. These are also modules that are returned by a Get-Module -ListAvailable command.

If the value of the Module parameter is * (all), Update-Help attempts to update help for all installed modules, including modules that don't support Updatable Help. This command typically generates many errors as the cmdlet encounters modules that don't support Updatable Help.

How to update help from a file share

To support computers that aren't connected to the internet, or to control or streamline help updating in an enterprise, use the Save-Help cmdlet. The Save-Help cmdlet downloads help files from the internet and saves them in a filesystem directory that you specify.

Save-Help compares the help files in the specified directory to the newest help files that are available for each module. If the directory has no help files or newer help files are available for the module, the Save-Help cmdlet downloads the new files from the internet. However, it doesn't unwrap or install the help files.

To install or update the help files on a computer from help files that were saved to a filesystem directory, use the SourcePath parameter of the Update-Help cmdlet. The Update-Help cmdlet identifies the newest help files, unwraps and validates them, and installs them in the language-specific subdirectories of the module directories.

For example, to save help for all installed modules to the \\Server\Share directory, type:

Save-Help -DestinationPath \\Server\Share

Then, to update help from the \\Server\Share directory, type:

Update-Help -SourcePath \\Server\Share

The following examples show the use of Save-Help to save help for modules that aren't installed on the local computer. In this example, the administrator runs Save-Help to save the help for the DhcpServer module from an internet-connected client computer, without installing the DhcpServer module or DHCP Server role on the local computer.

Option 1: Run Invoke-Command to get the PSModuleInfo object for the remote module, save it in a variable, $m, and then run Save-Help on the PSModuleInfo object by specifying the variable $m as the module name.

$invokeCommandSplat = @{
    ComputerName = 'RemoteServer'
    ScriptBlock = { Get-Module -Name DhcpServer -ListAvailable }
}
$m = Invoke-Command @invokeCommandSplat
Save-Help -Module $m -DestinationPath C:\SavedHelp

Option 2: Open a PSSession targeted at the computer that's running the DHCP Server module, to get the PSModuleInfo object for the module, save it in a variable $m, and then run Save-Help on the object that's saved in the $m variable.

$s = New-PSSession -ComputerName RemoteServer
$m = Get-Module -PSSession $s -Name DhcpServer -ListAvailable
Save-Help -Module $m -DestinationPath C:\SavedHelp

Option 3: Open a CIM session, targeted at the computer that's running the DHCP Server module, to get the PSModuleInfo object for the module, save it in a variable $m, and then run Save-Help on the object that's saved in the $m variable.

$c = New-CimSession -ComputerName RemoteServer
$m = Get-Module -CimSession $c -Name DhcpServer -ListAvailable
Save-Help -Module $m -DestinationPath C:\SavedHelp

In the following example, the administrator installs help for the DHCP Server module on a computer that doesn't have network access.

First, run Export-Clixml to export the PSModuleInfo object to a shared folder or to removable media.

$m = Get-Module -Name DhcpServer -ListAvailable
Export-Clixml -Path E:\UsbDrive\DhcpModule.xml -InputObject $m

Next, transport the removable media to a computer that has internet access, and then import the PSModuleInfo object with Import-Clixml. Run Save-Help to save the Help for the imported DhcpServer module PSModuleInfo object.

$deserialized_m = Import-Clixml E:\UsbDrive\DhcpModule.xml
Save-Help -Module $deserialized_m -DestinationPath E:\UsbDrive\SavedHelp

Finally, transport the removable media back to the computer that doesn't have network access, and then install the help by running Update-Help.

Update-Help -Module DhcpServer -SourcePath E:\UsbDrive\SavedHelp

Without parameters, Save-Help downloads help for all modules in the session and for all installed modules that support Updatable Help. To be included, modules must be installed in directories that are listed in the value of the $env:PSModulePath environment variable, on either the local computer or on a remote computer for which you want to save help. These are also modules that are returned by running a Get-Help -ListAvailable command.

How to update help files in different languages

By default, the Update-Help and Save-Help cmdlets download help in the UI culture and language that's set for Windows on the local computer. If help files for the specified modules aren't available in the local UI culture, Update-Help and Save-Help use the Windows language fallback rules to find the best supported language.

However, you can use the UICulture parameters of the Update-Help and Save-Help cmdlets to download and install help files in any UI cultures in which they're available.

For example, to save the newest help files for all modules on the session in Japanese (ja-Jp) and French (fr-FR), type:

Save-Help -Path \Server\Share -UICulture ja-jp, fr-fr

If help files for the modules aren't available in the languages that you specified, the Update-Help and Save-Help cmdlets return an error message that lists the languages in which help for each module is available so you can choose the alternative that best meets your needs.

Note

Currently, Updateable Help content is only published in English (en-US).

How to use online help

If you can't or choose not to update the help files on your local computer, you can still get the newest help files online.

To open the online help topic for any cmdlet or function, use the Online parameter of the Get-Help cmdlet.

For example, the following command opens the online help topic for the Get-Job cmdlet in your default internet browser:

Get-Help Get-Job -Online

To get online help for a script, use the Online parameter and the full path to the script.

The Online parameter doesn't work with About topics. To see the about topics for PowerShell, including help topics about the PowerShell language, see PowerShell About Topics.

How to minimize or prevent internet downloads

To minimize internet downloads and provide Updatable Help to users who aren't connected to the internet, use the Save-Help cmdlet. Download help from the internet and save it to a network share. Then, create a Group Policy setting or scheduled job that runs an Update-Help command on all computers. Set the value of the SourcePath parameter of the Update-Help cmdlet to the network share.

To prevent users who have internet access from downloading Updatable Help from the internet, use the Set the default source path for Update-Help Group Policy setting.

This Group Policy setting implicitly adds the SourcePath parameter, with the filesystem location that you specify, to every Update-Help command on every affected computer. Users can use the SourcePath parameter explicitly to specify a different filesystem location, but they can't exclude the SourcePath parameter and download help from the internet.

Note

The Set the default source path for Update-Help group policy setting appears under Computer Configuration and User Configuration. However, only the policy setting under Computer Configuration is effective. The policy setting under User Configuration is ignored.

For more information, see about_Group_Policy_Settings.

How to update help for non-standard modules

To update or save help for a module that's not returned by the ListAvailable parameter of the Get-Module cmdlet, import the module into the current session before running an Update-Help or Save-Help command. On a remote computer, before running the Save-Help command, import the module into the current Session, or Invoke-Command script block, that's connected to the remote computer.

When the module is in the current session, run the Update-Help or Save-Help cmdlets without parameters, or use the Module parameter to specify the module name.

The Module parameters of the Update-Help and Save-Help cmdlets accept only a module name. They don't accept the path to a module file.

Use this technique to update or save help for any module that's not returned by the ListAvailable parameter of the Get-Module cmdlet, such as a module that's installed in a location that's not listed in the $env:PSModulePath environment variable, or a module that's not well-formed (the module directory doesn't contain at least one file whose basename is the same as the directory name).

How to support updatable help

If you author a module, you can support online help and Updatable Help for your modules. For more information, see Supporting Updatable Help and Supporting Online Help.

Updatable help not available for PowerShell snap-ins or comment-based help.

Remarks

The Update-Help and Save-Help cmdlets aren't supported on Windows Preinstallation Environment (Windows PE).

See also