Understanding the PowerShell Cmdlet: Remove-CimSession

Welcome back to Wahmans Powershell blog!

Today, we will dive into a useful cmdlet in PowerShell for managing CIM sessions: Remove-CimSession. This cmdlet is an essential tool for cleaning up CIM (Common Information Model) sessions when automation or remote management tasks are completed. It’s especially relevant in scripts that utilize WMI or CIM to query remote systems.

What Does Remove-CimSession Do?

According to Microsoft’s documentation, Remove-CimSession “removes one or more CIM sessions.” CIM sessions are used to interact with remote computers using the WS-Man protocol, often as an alternative to DCOM connections.

Why Is This Important?

Maintaining open CIM sessions can consume system resources and lead to issues if not properly managed. Therefore, knowing how to remove them when they are no longer needed is good scripting hygiene.

Let’s Walk Through Some Examples

Example 1: Remove a Single CIM Session

Perfect for beginners, this example shows how to create and then remove a single CIM session.

PS> $session = New-CimSession -ComputerName "localhost"
PS> Remove-CimSession -CimSession $session

Here we create a CIM session to the local machine and then immediately remove it.

Example 2: Remove Multiple CIM Sessions

Suppose you’ve created multiple sessions. You can remove all of them at once:

PS> $session1 = New-CimSession -ComputerName "Server01"
PS> $session2 = New-CimSession -ComputerName "Server02"
PS> Remove-CimSession -CimSession $session1, $session2

Easy and efficient—just pass them as an array to the -CimSession parameter.

Example 3: Remove All Existing CIM Sessions

To remove all active CIM sessions, use Get-CimSession in combination with Remove-CimSession:

PS> $allSessions = Get-CimSession
PS> Remove-CimSession -CimSession $allSessions

This approach is useful for cleanup routines in your scripts.

Example 4: Removing Sessions by Filtering with Where-Object

In more advanced scenarios, you might want to delete sessions based on certain conditions such as computer name:

PS> Get-CimSession | Where-Object { $_.ComputerName -eq 'Server01' } | Remove-CimSession

With this, you only remove the sessions related to ‘Server01’, keeping others intact.

Conclusion

Remove-CimSession is a small but mighty cmdlet in PowerShell that ensures you keep your session management tidy and efficient. Whether you’re a beginner or an advanced user, knowing how to remove sessions properly is a vital skill for effective scripting.

Happy scripting, and I will see you in the next post!