When you install a new app on your smart phone, you actually ending enabling your phone to do more things that it originally couldn’t do out of the box. In powershell we can add features (e.g. new cmdlets) to powershell in the same way, but by installing extensions. There are two types of extension that you install:
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- modules
Modules are are better than PSSnapin, because they are more self-contained and easier to distribute, also they don’t require advanced registration, instead you simply drop them in certain directories, which is covered later)
PSSnapins
first lets talk about PSSnapins
Get-PSSnapin -Registered
This lists all the available snapins that have been installed (regardless of whether they are active or not) but excludes snapins that came pre-installed with powershell.
Note, I think PSSnapin gets installed as part of a much larger software, e.g. things like microsoft sql developer, sharepoint,….etc. I don’t think they come as standalones that you can download from the internet.
This lists all the snapins that are currently running (including snapins that came preinstalled with powershell):
Get-PSSnapin
If the above command shows something that you want to load, then you can load it using the following command:
add-pssnapin -name {snapinname}
Installing a snapin introduces one or both of the following:
- psdrive/psprovider
- cmdlets
To see what new commands a snapin has introduced, do:
Get-Command -name PSSnapin {snapin's name}
Note: the above doesn’t work.
Unfortunately there are no way to to see what psdrives have been added by a PSSnapin. The only way to check this by first running the following command before installing the PSSnapin:
get-psprovider
This should output something like:
PS C:\> Get-PSProvider
Name Capabilities Drives
---- ------------ ------
WSMan Credentials {WSMan}
Alias ShouldProcess {Alias}
Environment ShouldProcess {Env}
FileSystem Filter, ShouldProcess {C, E, A, D}
Function ShouldProcess {Function}
Registry ShouldProcess, Transactions {HKLM, HKCU}
Variable ShouldProcess {Variable}
Certificate ShouldProcess {cert}
And then run the above command again to see what new items are now listed.
Note: get-psprovider is what you use to start exploring the registry. This works in the same way as using regedit, but via the command line.
############ detour – start
Note: A lot of softwares, e.g. scp comes with it’s own command line shell. It could be that this command line shell is actually just a powershell
shell with the correct module/snapin preloaded. To check if that is really the case, right click the custom shell icon then do:
properties -=> find-target
Here you will find something like this:
%windir%\system32\WindowsPowershell\v1.0\powershell.exe -noexit -command import-module {module-name}
In these scenarios, instead of running this tool, you can simply open up powershell and run the “import-module {module-name}” command to achieve the same results.
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modules
Modules are designed to be a little more:
- self-contained
- easier to distribute
- dont require advanced registration
You can find and download modules from the internet, here are some popular module hosting websites:
http://powershell.codeplex.com/site/search?query=powershell&ac=3
Note, if you download them from the internet, then you first need to:
rightclick the zipped file -> properties -> unblock.
Powershell automatically looks for available modules by looking at list of certain paths that are defined in the “psmodulepath” variable (which is stored in the “env” psdrive):
Get-Content Env:\PSModulePath C:\Documents and Settings\SChowdhury\My Documents\WindowsPowerShell\Modules;C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\
The cool thing about modules is that they are really easy to install (and activate). All you have to do is copy them into one of the folders defined in “Env:\PSModulePath”.
Once you have placed the module into one of the “approved” folders, you can then check that the module has been installed and activated by running the following command:
PS C:\> Get-Module -ListAvailable
Directory: C:\Users\SChowdhury\Documents\WindowsPowerShell\Modules
ModuleType Name ExportedCommands
---------- ---- ----------------
Script hmrctool {new-hmrcobject, get-maths}
Directory: C:\Program Files (x86)\PowerShell Community Extensions\Pscx3
ModuleType Name ExportedCommands
---------- ---- ----------------
Script Pscx {Add-PathVariable, Clear-MSMQueue, ConvertFrom-Base64, ConvertTo-Base64...}
In the above example I also installed a really useful module called “Pscx” (short for “Powershell Community Extensions”) which you can download from here:
http://pscx.codeplex.com/
Note: in this instance, the module is provided in the form of an msi file….which makes it even easier by walking you through an installation wizard. This msi file, behind the scene actually, use the unblock-file command (covered later), adds a new approved path to the $env:psmodulepath variable, and then place the module into that path.
Note: whenever you download a module from the internet, Windows tags these downaloads as “internet downloads” and fore safety+security reasons it will not automatically install+activate them. In this you can simply first use unblock-file command.
By the way, if you want to see what new commands are available, you can either do:
PS C:\> Get-Module -ListAvailable
This only gives a preview, so you can drill down like this:
PS C:\> (Get-Module -ListAvailable | Where-Object -FilterScript {$_.Name -match "Pscx"}).ExportedCommands
But a much better way is to simply do:
PS C:\> Get-Command -Module pscx CommandType Name ModuleName ----------- ---- ---------- Alias Resize-Bitmap Pscx Function Add-DirectoryLength Pscx Function Add-ShortPath Pscx Function Dismount-VHD Pscx Function Edit-File Pscx Function Edit-HostProfile Pscx Function Edit-Profile Pscx Function Enable-OpenPowerShellHere Pscx Function Get-ExecutionTime Pscx Function Get-Help Pscx Function Get-Parameter Pscx Function Get-ScreenCss Pscx Function Get-ScreenHtml Pscx Function Get-ViewDefinition Pscx Function help Pscx Function Import-VisualStudioVars Pscx Function Invoke-BatchFile Pscx Function Invoke-Elevated Pscx Function Invoke-GC Pscx Function Invoke-Method Pscx Function Invoke-NullCoalescing Pscx Function Invoke-Ternary Pscx Function less Pscx Function Mount-VHD Pscx Function Out-Speech Pscx Function QuoteList Pscx Function QuoteString Pscx Function Resolve-ErrorRecord Pscx Function Resolve-HResult Pscx Function Resolve-WindowsError Pscx Function Set-LocationEx Pscx Function Set-ReadOnly Pscx Function Set-Writable Pscx Function Show-Tree Pscx Function Start-PowerShell Pscx Function Stop-RemoteProcess Pscx Filter New-HashObject Pscx Cmdlet Add-PathVariable Pscx Cmdlet Clear-MSMQueue Pscx Cmdlet ConvertFrom-Base64 Pscx Cmdlet ConvertTo-Base64 Pscx Cmdlet ConvertTo-MacOs9LineEnding Pscx Cmdlet ConvertTo-Metric Pscx Cmdlet ConvertTo-UnixLineEnding Pscx Cmdlet ConvertTo-WindowsLineEnding Pscx Cmdlet Convert-Xml Pscx Cmdlet Disconnect-TerminalSession Pscx Cmdlet Expand-Archive Pscx Cmdlet Export-Bitmap Pscx Cmdlet Format-Byte Pscx Cmdlet Format-Hex Pscx Cmdlet Format-Xml Pscx Cmdlet Get-ADObject Pscx Cmdlet Get-AdoConnection Pscx Cmdlet Get-AdoDataProvider Pscx Cmdlet Get-Clipboard Pscx Cmdlet Get-DhcpServer Pscx Cmdlet Get-DomainController Pscx Cmdlet Get-DriveInfo Pscx Cmdlet Get-EnvironmentBlock Pscx Cmdlet Get-FileTail Pscx Cmdlet Get-FileVersionInfo Pscx Cmdlet Get-ForegroundWindow Pscx Cmdlet Get-Hash Pscx Cmdlet Get-HttpResource Pscx Cmdlet Get-LoremIpsum Pscx Cmdlet Get-MountPoint Pscx Cmdlet Get-MSMQueue Pscx Cmdlet Get-OpticalDriveInfo Pscx Cmdlet Get-PathVariable Pscx Cmdlet Get-PEHeader Pscx Cmdlet Get-Privilege Pscx Cmdlet Get-PSSnapinHelp Pscx Cmdlet Get-ReparsePoint Pscx Cmdlet Get-RunningObject Pscx Cmdlet Get-ShortPath Pscx Cmdlet Get-TerminalSession Pscx Cmdlet Get-TypeName Pscx Cmdlet Get-Uptime Pscx Cmdlet Import-Bitmap Pscx Cmdlet Invoke-AdoCommand Pscx Cmdlet Invoke-Apartment Pscx Cmdlet Join-String Pscx Cmdlet New-Hardlink Pscx Cmdlet New-Junction Pscx Cmdlet New-MSMQueue Pscx Cmdlet New-Shortcut Pscx Cmdlet New-Symlink Pscx Cmdlet Out-Clipboard Pscx Cmdlet Ping-Host Pscx Cmdlet Pop-EnvironmentBlock Pscx Cmdlet Push-EnvironmentBlock Pscx Cmdlet Read-Archive Pscx Cmdlet Receive-MSMQueue Pscx Cmdlet Remove-MountPoint Pscx Cmdlet Remove-ReparsePoint Pscx Cmdlet Resolve-Host Pscx Cmdlet Send-MSMQueue Pscx Cmdlet Send-SmtpMail Pscx Cmdlet Set-BitmapSize Pscx Cmdlet Set-Clipboard Pscx Cmdlet Set-FileTime Pscx Cmdlet Set-ForegroundWindow Pscx Cmdlet Set-PathVariable Pscx Cmdlet Set-Privilege Pscx Cmdlet Set-VolumeLabel Pscx Cmdlet Skip-Object Pscx Cmdlet Split-String Pscx Cmdlet Stop-TerminalSession Pscx Cmdlet Test-AlternateDataStream Pscx Cmdlet Test-Assembly Pscx Cmdlet Test-MSMQueue Pscx Cmdlet Test-Script Pscx Cmdlet Test-UserGroupMembership Pscx Cmdlet Test-Xml Pscx Cmdlet Write-BZip2 Pscx Cmdlet Write-Clipboard Pscx Cmdlet Write-GZip Pscx Cmdlet Write-Tar Pscx Cmdlet Write-Zip Pscx
Note: if you run just “get-module” it will only list modules that have been activated. This can be useful to identify any modules that have failed to load properly, as they won’t appear in this list.