"Fossies" - the Fresh Open Source Software Archive

Member "PowerShell-7.2.6/docs/learning-powershell/powershell-beginners-guide.md" (11 Aug 2022, 11159 Bytes) of package /linux/misc/PowerShell-7.2.6.tar.gz:

PowerShell Beginner’s Guide

If you are new to PowerShell, this document will walk you through a few examples to give you some basic ideas of PowerShell. We recommend that you open a PowerShell console/session and type along with the instructions in this document to get most out of this exercise.

Launch PowerShell Console/Session

First you need to launch a PowerShell session by following the Installing PowerShell Guide.

Getting Familiar with PowerShell Commands

In this section, you will learn how to

• create a file, delete a file and change file directory
• discover what version of PowerShell you are currently using
• exit a PowerShell session
• get help if you needed
• find syntax of PowerShell cmdlets
• and more

As mentioned above, PowerShell commands are designed to have Verb-Noun structure, for instance Get-Process, Set-Location, Clear-Host, etc. Let’s exercise some of the basic PowerShell commands, also known as cmdlets.

Please note that we will use the PowerShell prompt sign PS /> as it appears on Linux in the following examples. It is shown as PS C:\> on Windows.

1. Get-Process: Gets the processes that are running on the local computer or a remote computer.

   By default, you will get data back similar to the following:

   PS /> Get-Process
   
   Handles   NPM(K)    PM(K)     WS(K)     CPU(s)     Id    ProcessName
   -------  ------     -----     -----     ------     --    -----------
       -      -          -           1      0.012     12    bash
       -      -          -          21     20.220    449    powershell
       -      -          -          11     61.630   8620    code
       -      -          -          74    403.150   1209    firefox
   
   …

   Only interested in the instance of Firefox process that is running on your computer?

   Try this:

   PS /> Get-Process -Name firefox
   
   Handles   NPM(K)    PM(K)     WS(K)    CPU(s)     Id   ProcessName
   -------  ------     -----     -----    ------     --   -----------
       -      -          -          74   403.150   1209   firefox

   Want to get back more than one process? Then just specify process names and separate them with commas.

   PS /> Get-Process -Name firefox, powershell
   Handles   NPM(K)    PM(K)     WS(K)    CPU(s)     Id   ProcessName
   -------  ------     -----     -----    ------     --   -----------
       -      -          -          74   403.150   1209   firefox
       -      -          -          21    20.220    449   powershell

2. Clear-Host: Clears the display in the host program.

   PS /> Get-Process
   PS /> Clear-Host

   Type too much just for clearing the screen?

   Here is how the alias can help.

3. Get-Alias: Gets the aliases for the current session.

   Get-Alias
   
   CommandType     Name
   -----------     ----
   …
   
   Alias           cd -> Set-Location
   Alias           cls -> Clear-Host
   Alias           clear -> Clear-Host
   Alias           copy -> Copy-Item
   Alias           dir -> Get-ChildItem
   Alias           gc -> Get-Content
   Alias           gmo -> Get-Module
   Alias           ri -> Remove-Item
   Alias           type -> Get-Content
   …

   As you can see cls or clear is an alias of Clear-Host.

   Now try it:

   PS /> Get-Process
   PS /> cls

4. cd -> Set-Location: Sets the current working location to a specified location.

   PS /> Set-Location /home
   PS /home>

5. dir -> Get-ChildItem: Gets the items and child items in one or more specified locations.

   # Get all files under the current directory:
   PS /> Get-ChildItem
   
   # Get all files under the current directory as well as its subdirectories:
   PS /> cd $home
   PS /home/jen> dir -Recurse
   
   # List all files with "txt" file extension.
   PS /> cd $home
   PS /home/jen> dir –Path *.txt -Recurse

6. New-Item: Creates a new item.

   # An empty file is created if you type the following:
   PS /home/jen> New-Item -Path ./test.txt
   
   
       Directory: /home/jen
   
   
   Mode                LastWriteTime         Length  Name
   ----                -------------         ------  ----
   -a----         7/7/2016   7:17 PM              0  test.txt

   You can use the -Value parameter to add some data to your file.

   For example, the following command adds the phrase Hello world! as a file content to the test.txt.

   Because the test.txt file exists already, we use -Force parameter to replace the existing content.

   PS /home/jen> New-Item -Path ./test.txt -Value "Hello world!" -Force
   
       Directory: /home/jen
   
   
   Mode                LastWriteTime         Length  Name
   ----                -------------         ------  ----
   -a----         7/7/2016   7:19 PM             24  test.txt

   There are other ways to add some data to a file.

   For example, you can use Set-Content to set the file contents:

   PS /home/jen>Set-Content -Path ./test.txt -Value "Hello world again!"

   Or simply use > as below:

   # create an empty file
   "" > test.txt
   
   # set "Hello world!" as content of test.txt file
   "Hello world!!!" > test.txt

   The pound sign # above is used for comments in PowerShell.

7. type -> Get-Content: Gets the content of the item at the specified location.

   PS /home/jen> Get-Content -Path ./test.txt
   PS /home/jen> type -Path ./test.txt
   
   Hello world again!

8. del -> Remove-Item: Deletes the specified items.

   This cmdlet will delete the file /home/jen/test.txt:

   PS /home/jen> Remove-Item ./test.txt

9. $PSVersionTable: Displays the version of PowerShell you are currently using.

   Type $PSVersionTable in your PowerShell session, you will see something like below. "PSVersion" indicates the PowerShell version that you are using.

   Name                           Value
   ----                           -----
   PSVersion                      6.0.0-alpha
   PSEdition                      Core
   PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
   BuildVersion                   3.0.0.0
   GitCommitId                    v6.0.0-alpha.12
   CLRVersion
   WSManStackVersion              3.0
   PSRemotingProtocolVersion      2.3
   SerializationVersion           1.1.0.1

10. Exit: To exit the PowerShell session, type exit.

    exit

Need Help?

The most important command in PowerShell is possibly the Get-Help, which allows you to quickly learn PowerShell without having to search around the internet.

The Get-Help cmdlet also shows you how PowerShell commands work with examples.

It shows the syntax and other technical information of the Get-Process cmdlet.

PS /> Get-Help -Name Get-Process

It displays the examples how to use the Get-Process cmdlet.

PS />Get-Help -Name Get-Process -Examples

If you use -Full parameter, for example, Get-Help -Name Get-Process -Full, it will display more technical information.

Discover Commands Available on Your System

You want to discover what PowerShell cmdlets available on your system? Just run Get-Command as below:

PS /> Get-Command

If you want to know whether a particular cmdlet exists on your system, you can do something like below:

PS /> Get-Command Get-Process

If you want to know the syntax of Get-Process cmdlet, type:

PS /> Get-Command Get-Process -Syntax

If you want to know how to use the Get-Process, type:

PS /> Get-Help Get-Process -Example

PowerShell Pipeline |

Sometimes when you run Get-ChildItem or "dir", you want to get a list of files and folders in a descending order. To achieve that, type:

PS /home/jen> dir | Sort-Object -Descending

Say you want to get the largest file in a directory

PS /home/jen> dir | Sort-Object -Property Length -Descending | Select-Object -First 1


    Directory: /home/jen


Mode                LastWriteTime       Length  Name
----                -------------       ------  ----
-a----        5/16/2016   1:15 PM        32972  test.log

How to Create and Run PowerShell scripts

You can use Visual Studio Code or your favorite editor to create a PowerShell script and save it with a .ps1 file extension. For more details, see Create and Run PowerShell Script Guide

Recommended Training and Reading

• Video: Get Started with PowerShell from Channel9
• eBooks from PowerShell.org
• eBooks List by Martin Schvartzman
• Tutorial from MVP
• Script Guy blog: The best way to Learn PowerShell
• Understanding PowerShell Module
• How and When to Create PowerShell Module by Adam Bertram
• Video: PowerShell Remoting in Depth from Channel9
• PowerShell Basics: Remote Management from ITPro
• Running Remote Commands from PowerShell Web Docs
• Samples for Writing a PowerShell Script Module
• Writing a PowerShell module in C#
• Examples of Cmdlets Code

Commercial Resources

• Windows PowerShell in Action by Bruce Payette
• Windows PowerShell Cookbook by Lee Holmes