Microsoft Virtual Academy: PowerShell M07 (Part 2)

Here we are module 7 only two more.  This is a short segment but lots of information.  To keep things short I have split it among three posts.  Check the Overview to see what is covered under this post.

To start your own learning check out Microsoft Virtual Academy:
(http://www.microsoftvirtualacademy.com/training-courses/getting-started-with-powershell-3-0-jump-start?o=3276#?fbid=aVs9FfAH2DJ)
(rewritten based on my notes available here: https://drive.google.com/file/d/0B1fwreWrAZioQ28xTmx0d29HUzQ/edit?usp=sharing)

Module 7: "Getting prepared for automation" consists of 2 video segments totaling ≈ 26 minutes along with a PowerPoint of 12 slides.

Overview

• Execution Policy (http://cleeit.blogspot.com/2014/01/MVA-powershell-m07-part1.html)
• What is it
• How to set it
• Signing scripts (http://cleeit.blogspot.com/2014/01/MVA-powershell-m07-part1.html)
• Create
• Load
• Sign
• Results
• Variables
• Defining
• Prompt for input (Read-Host)
• Output to screen (http://cleeit.blogspot.com/2014/01/MVA-powershell-m07-part3.html)
• Write-Host
• Write-Warning/Error/Debug

Variables

   Variables are a huge part the power o f PowerShell.  Variables can store not just numerical or string for output but also cmdlets for recall later, executed against, or even run method if supported.  A variable is defined by $ and can be recalled by $name.  Variables are not saved after shell or session is closed.  Check out the slides for how to use variables and quotes.

Example of string for output:

$myvar="HelloWorld"

        Sets HelloWorld into variable myvar

$myvar

        To call variable we enter it's name

HelloWorld

        Value returned from call

Example of numerical 

$myvar="1354"

        Sets HelloWorld into variable myvar

$myvar

        To call variable we enter it's name

1354

        Value returned from call

Example of cmdlet:

$myvar=Get-Service bits

        Sets cmdlet Get-Service to variable myvar

$myvar

        Calls variable myvar which executes stored cmdlet Get-Service bits

Status          Name         DisplayName
------          ----         -----------
Running         bits         Background Intelligent Transfer Ser...

        Results of cmdlet

Example of cmdlet executed against:

$myvar=Get-Service bits

        Sets cmdlet Get-Service to variable myvar

$myvar | gm

        Calls variable myvar which executes stored cmdlet Get-Service bits and runs through pipe get-member

                 TypeName: System.ServiceProcess.ServiceController

Name                                                  MemberType                  Definition
----                                                        ----------                            ----------
Name                                                  AliasProperty                 Name = ServiceName
RequiredServices                            AliasProperty                  RequiredServices = ServicesDependedOn
Disposed                                           Event                                System.EventHandler Disposed(System.Object, System.EventArgs)
Close                                                  Method                             void Close()
Continue                                            Method                              void Continue()
....

        Results of cmdlet

Example of cmdlet method:

$myvar=Get-Service bits

        Sets cmdlet Get-Service to variable myvar

$myvar.status

        Calls variable myvar which executes stored cmdlet Get-Service bits but only outputs Status

Running

        Results of cmdlet

  Variables are also not limited to a single word or continues string for a name.  By using the brackets {} you can use phrases as the variable name.

${This is a test}=4

         Sets value of 4 to variable This is a test

${This is a test}

        Call variable This is a test

4

        Results

Read-Host
  Now it is all nice that we can static set a variable but what if I want to ask the user for information (name/amount/etc).  To do this we use:

Read-Host  "Message here"

To save this to a variable we just append $var = to the front of string as below:

$myvar = Read-Host "Enter Computer name:"

        Prompts the user to enter a value and saves it to variable myvar

Check out the rest of this segment:
Part 1: http://cleeit.blogspot.com/2014/01/MVA-powershell-m07-part1.html
Part 3: http://cleeit.blogspot.com/2014/01/MVA-powershell-m07-part3.html