Understanding Cmdlets

Overview:

The following section goes over what cmdlets are and common cmdlets utilized within Powershell.

Common Cmdlets

What are Cmdlets?

• Cmdlets are lightweight commands used in the PowerShell environment. They follow a Verb-Noun naming pattern.

Common Cmdlets:

• Get-Help: Provides help information for cmdlets.

  Get-Help Get-Process

• Get-Command: Lists all available cmdlets and functions.

  Get-Command

• Get-Service: Retrieves the status of services on a system.

  Get-Service

• Get-Process: Gets the processes that are running on a system.

  Get-Process

• Set-Variable: Sets the value of a variable.

  Set-Variable -Name "testVar" -Value "Hello, PowerShell"

• Remove-Item: Deletes files, directories, or registry keys.

  Remove-Item -Path "C:\Temp\test.txt"

Examples Using Cmdlets:

• Retrieve a list of all services:

  Get-Service

• Get detailed help for a cmdlet:

  Get-Help Get-Process -Detailed

• List all commands available in your PowerShell session:

  Get-Command

Using the Pipeline

What is a Pipeline?

• The pipeline (|) is a powerful feature in PowerShell that allows you to pass the output of one cmdlet as input to another cmdlet.

Basic Pipeline Usage:

• Example:

  Get-Process | Sort-Object -Property CPU

Filtering Output:

• Use Where-Object to filter objects based on property values.

• Example:

  Get-Process | Where-Object { $_.CPU -gt 100 }

Selecting Properties:

• Use Select-Object to select specific properties of objects.

• Example:

  Get-Process | Select-Object -Property Name, CPU

Sorting Output:

• Use Sort-Object to sort objects by property values.

• Example:

  Get-Process | Sort-Object -Property CPU -Descending

Example: Using Multiple Cmdlets in a Pipeline

Get-Service | Where-Object { $_.Status -eq "Running" } | Sort-Object -Property DisplayName

Filtering and Formatting Output

Filtering Data:

• Where-Object: Filters objects based on a specified condition.

  Get-Process | Where-Object { $_.CPU -gt 100 }

Formatting Data:

• Format-Table: Formats output as a table.

  Get-Process | Format-Table -Property Name, CPU -AutoSize

• Format-List: Formats output as a list.

  Get-Process | Format-List -Property Name, CPU

Examples:

• List all running processes using a table format:

  Get-Process | Format-Table -Property Name, CPU -AutoSize

• List all services that are running, sorted by display name:

  Get-Service | Where-Object { $_.Status -eq "Running" } | Sort-Object -Property DisplayName

Practical Exercises

Exercise 1: Using Basic Cmdlets

• Retrieve a list of all processes running on your system:

  Get-Process

• Retrieve detailed help for the Get-Service cmdlet:

  Get-Help Get-Service -Detailed

Exercise 2: Using the Pipeline

• List all running processes and sort them by CPU usage:

  Get-Process | Sort-Object -Property CPU

• Filter the processes to show only those using more than 100 units of CPU:

  Get-Process | Where-Object { $_.CPU -gt 100 }

Exercise 3: Filtering and Formatting Output

• List all running services and format the output as a table:

  Get-Service | Where-Object { $_.Status -eq "Running" } | Format-Table -Property DisplayName, Status -AutoSize

Exercise 4: Combining Cmdlets in a Pipeline

• Combine Get-Service, Where-Object, and Format-Table to list all running services, sorted by their display names:

  Get-Service | Where-Object { $_.Status -eq "Running" } | Sort-Object -Property DisplayName | Format-Table -Property DisplayName, Status -AutoSize