Mastering the 'Get-Command' PowerShell Command (with Examples)

The Get-Command cmdlet is an essential utility in PowerShell that allows users to retrieve comprehensive lists of available commands, including aliases, cmdlets, functions, and applications accessible from the command line. This command serves as both a tool for discovery and a starting point for scripting or automating IT tasks.

Use case 1: Listing All Available PowerShell Commands on the Computer

Code:

Get-Command

Motivation:

When you are getting started with PowerShell or need an overview of the diverse range of commands available for use, Get-Command without any parameters gives you a complete overview of all PowerShell commands accessible on your computer. It is particularly useful when you want to familiarize yourself with the command environment or prepare for scripting tasks.

Explanation:

The command lacks additional parameters, which means it will return all commands that are installed and accessible on the system, including aliases, cmdlets, functions, scripts, and applications.

Example Output:

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Alias           % -> ForEach-Object
Alias           ? -> Where-Object
Cmdlet          Add-Content                                        7.0.0.0    Microsoft.PowerShell.Management
Function        Write-Host
Application     notepad.exe
...

Use case 2: Listing All Available PowerShell Commands in the Current Session

Code:

Get-Command -ListImported

Motivation:

For users who wish to focus their attention on a specific session context, this use case is critical. It allows users to see only those commands that have been imported and are readily available in the current PowerShell session, without listing the potentially overwhelming full set of commands installed on the machine.

Explanation:

The -ListImported parameter filters the results, listing only those commands imported into the current session. This helps streamline your view and avoid clutter.

Example Output:

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Cmdlet          Get-Process                                        7.0.0.0    Microsoft.PowerShell.Management
Alias           % -> ForEach-Object
...

Use case 3: Listing Only PowerShell Aliases, Cmdlets, and Functions on the Computer

Code:

Get-Command -Type Alias, Cmdlet, Function

Motivation:

This example provides a more focused list of elements that are specifically related to PowerShell: aliases, cmdlets, and functions. It’s beneficial when you’re interested in scripting within PowerShell’s domain and don’t need details about applications and external executables.

Explanation:

The -Type parameter is used here with specific arguments Alias, Cmdlet, and Function. These arguments instruct PowerShell to filter the output to include only the selected types.

Example Output:

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Alias           cd -> Set-Location
Cmdlet          Start-Service                                      7.0.0.0    Microsoft.PowerShell.Management
Function        Get-Help
...

Use case 4: Listing Only Programs or Commands Available on PATH in the Current Session

Code:

Get-Command -Type Application

Motivation:

When needing an understanding of which executable files are readily accessible from your system’s environment path, this use case is essential. It’s useful for checking available applications that you can call directly from the command line without full paths.

Explanation:

The -Type parameter is used with the argument Application. This specifies that PowerShell should filter and list only the programs or applications accessible through the system’s PATH variable.

Example Output:

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Application     chrome.exe
Application     code.exe
Application     notepad.exe
...

Use case 5: Listing PowerShell Commands by Module Name

Code:

Get-Command -Module Microsoft.PowerShell.Utility

Motivation:

This use case is particularly useful for administrators who need to utilize or explore commands within a specific module. It assists in understanding what utility-specific commands the module Microsoft.PowerShell.Utility offers.

Explanation:

The -Module parameter filters results based on the specified module name, in this case, Microsoft.PowerShell.Utility. This focuses the results solely on commands that belong to this module, providing a tailored view.

Example Output:

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Cmdlet          Get-Random                                         7.0.0.0    Microsoft.PowerShell.Utility
Cmdlet          Measure-Object                                     7.0.0.0    Microsoft.PowerShell.Utility
...

Use case 6: Getting Command Information by Name

Code:

Get-Command Get-Process

Motivation:

In situations where you require detailed information about a specific command, this example is invaluable. It provides metadata such as the command’s version, source module, and exact syntax, which is crucial when integrating it into scripts or automation workflows.

Explanation:

The command name Get-Process is provided directly as an argument to Get-Command. This tells PowerShell to retrieve comprehensive details about that specific command.

Example Output:

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Cmdlet          Get-Process                                        7.0.0.0    Microsoft.PowerShell.Management

Conclusion:

The PowerShell Get-Command cmdlet provides powerful ways to explore and retrieve information about available commands within a PowerShell session or on a computer system. Each use case focuses on different aspects of command discovery, whether you’re looking at session-specific, machine-specific, or module-specific command variants. By mastering these use cases, users can harness the full potential of PowerShell for a wide range of administrative and scripting tasks.