Create a Function to See if Your Drivers Are Signed
I created this PowerShell function to discover which of the drivers installed on my Windows 8 machine had been signed. At the heart of the function is a built-in Windows command called DriverQuery.
Create Get-Driver: Windows PowerShell Function
- Planning the Get-Driver Function
- How To Create a PowerShell Function
- Learning Points for Creating a PowerShell Function
- Problems of Creating a PowerShell Function
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Planning the Get-Driver Function
It's not easy for a beginner to create a PowerShell Function. There are at least 3 sections, and 4 syntax rules to master. The purpose of this function is to list which drivers have been digitally signed (Signed = TRUE).
1) Header Section – Help Comments and Function Description
I leave this section until I am comfortable with the function, only then do I add help notes, for example, .SYNOPSIS in <# ….Adding comments … #>.
2) PowerShell Function Parameters
Param(
List of parameters
My advice is to return to the parameter's section once you have the basic Process {DriverQuery instructions} working smoothly.
3) 'Process' is a Keyword in a Function
Scripting with Windows PowerShell is rewarding, the Process section contains the engine of your script. In my example below this section holds the logic defined by a series of If … ElseIf statements.
4) Begin and End
The keywords 'Begin' and 'End' are optional, I like to use Clear-Host in the Begin section, and I have displayed the time in the 'End' section of the script.
How To Create a Function: PowerShell Command Example
Function Global:Get-Driver {
<#
.SYNOPSIS
PowerShell function to enhance the built-in DriverQuery command
.DESCRIPTION
Includes parameters to filter for signed and unsigned drivers.
.EXAMPLE
Get-Driver -Signed
#>
[cmdletbinding()]
Param (
[Switch]$Unsigned,
[Switch]$Signed,
[Switch]$All
)
Begin {
Clear-Host
"Retrieving driver signing information …"
} # End of Begin section
Process {
If ($Signed){
$DrvSig = DriverQuery -Si | Select-String "True"
$DrvSig
"`n " + $DrvSig.count + " signed drivers, note TRUE column"
} # End of If
ElseIf ($UnSigned) {
$DrvU = DriverQuery -Si | Select-String "False"
$DrvU
"`n " + $DrvU.count + " unsigned drivers, note FALSE column"
} # End of first ElseIf
ElseIf ($All) {
DriverQuery -Si
} # End of second ElseIf
Else {
DriverQuery
} # End of the final Else
} # End of Process section
End {
"`n " + (Get-Date).DateTime
} # End of 'End' section
} # End of Get-Driver function
Three commands to try using my example function:
- Get-Driver
- Get-Driver -Signed
- Get-Help Get-Driver -Full
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Learning Points for Creating a PowerShell Function
- From scripting point of view, [Switch]$Signed enables you to oscillate from executing the base DriverQuery command, with executing modified code. Observe how appending -Signed results in : Select-String "True"
- From a user's perspective, think how typing the -switch will retrieve just the information you want, for example: Get-Driver -Unsigned
- In addition to providing the function's structure or wrapper, PowerShell supplies Select-String, which enhances the Windows QueryDriver command.
- As an aside, I also wanted to emphasise how PowerShell can run native Windows Scripting commands such as DriverQuery.
Problems of Creating a PowerShell Function
Firstly, there is the psychological problem that you can use Windows PowerShell commands perfectly well without bothering to create functions.
Secondly, there can be confusion for a beginner because there are so many terms vying for your attention, for example: param, process and synopsis.
Thirdly the syntax is fiddly; beginners get in a twist with the different types of bracket needed to create a PowerShell function.
There is good news, creating a PowerShell is satisfying. When you are starting out ignore factors such writing <# comments #>, and just concentrate on the action of the 'Process' section.
My technique was to learn by doing, building on success; gradually I began to embrace terms such as Global, [Switch] and to understand the significance of the brackets and the punctuation.
See more on PowerShell function parameters ยป
Summary of Creating Get-Driver Using DriverQuery
My aim is to provide useful PowerShell function examples complete with notes, by goal is that you can modify my code for your situation.
I created this cmdlet-style function out of a desire to discover if the drivers installed on my Windows 8 machine had been signed. At the heart of the function is a built-in Windows command called DriverQuery.
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See More PowerShell Function Parameters
• Scripting PowerShell Function • PowerShell Function Clear-Recyclebin • PowerShell Get-File
• Create PowerShell Function Get-ServiceStatus • PowerShell Function Get-Driver • PowerShell Outlook
• Show-BalloonTip • PowerShell Function Get-IPConfig • Free Permissions Analyzer
Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.
