Skip to content

Modules

Scope: finding, installing, and using PowerShell modules. All examples were run with PowerShell 7.5.

What a module is

A module is a package of commands — functions, cmdlets, aliases — you load into your session. The Az modules (Azure), Microsoft.Graph (Microsoft 365), Pester (testing), and thousands of community modules all work this way.

Finding and installing

Find-Module -Name Pester | Select-Object Name, Version
Install-Module -Name Pester -Scope CurrentUser
Import-Module Pester
  • Find-Module searches the PowerShell Gallery (powershellgallery.com) — the npm/PyPI of PowerShell.
  • -Scope CurrentUser installs to your profile, no admin needed. Prefer it over system-wide installs.
  • Import-Module loads it into the session. Many modules auto-load on first use, but explicit imports are clearer in scripts.

First time, you'll be asked to trust the gallery repository — answer yes (it's Microsoft's official registry).

Using installed modules

Get-Module -ListAvailable | Select-Object Name, Version
Get-Command -Module Pester

Get-Module -ListAvailable shows what's installed; Get-Command -Module <name> shows what a module provides.

Module scopes and versions

Install-Module -Name Az -Scope CurrentUser -RequiredVersion 12.0.0
Update-Module -Name Az
Uninstall-Module -Name Az -RequiredVersion 11.0.0

Multiple versions can coexist; Import-Module -RequiredVersion picks one. Update-Module upgrades. Clean up old versions occasionally — Az especially accumulates them.

Writing your own (the 30-second version)

# MyTools.psm1
function Get-Greeting {
    param([string]$Name = "stranger")
    "Hello, $Name!"
}
Export-ModuleMember -Function Get-Greeting

Import-Module ./MyTools.psm1
Get-Greeting -Name "Ada"

A .psm1 file is a module; Export-ModuleMember controls what's public. Add a .psd1 manifest (New-ModuleManifest) when you want versioning and metadata.

Trust notes

The Gallery is large and community-driven — same caution as npm applies: prefer modules from Microsoft or well-known publishers, check download counts and recent updates, and don't install obscure modules on production boxes without a look at the code.

Check

  • [ ] You can find, install (CurrentUser scope), and import a module
  • [ ] You know what the PowerShell Gallery is
  • [ ] You can list a module's commands

Next: Error Handling.