Quick Learn – PSMonday #6: Monday, June 6, 2016

Topic: Splatting and Hash Tables Continued

Notice: This post is a part of the PowerShell Monday series — a group of quick and easy to read mini lessons that briefly cover beginning and intermediate PowerShell topics. As a PowerShell enthusiast, this seemed like a beneficial way to ensure those around me at work were consistently learning new things about Windows PowerShell. At some point, I decided I would share these posts here, as well. Here’s the PowerShell Monday Table of Contents.

So, back to splatting: If you ever have a parameter that doesn’t need an assigned value, where the value is equal to true if the parameter is included, and false if it’s not — a switch parameter — then use $true or $false as the parameter value in the hash table. You can see an example of this below. Notice that in the example one of the parameter values wasn’t hardcoded, and instead was assigned using the value from another variable. Doing this isn’t always necessary, but it’s being shown, as an example for a time when it may be needed.

$Command = 'Get-ADUser'
$Params = @{
    Name = $Command
    ShowWindow = $true
}

Get-Help @Params

It should be said, that if you don’t include a switch parameter in the hash table, that it won’t be included when the cmdlet is run, and will therefore be false by default.

Let’s splat Send-MailMessage. This command, and its need for so many parameters and parameter values, makes it a great candidate for splatting, unlike the above Get-Help command where there was only two included parameters.

$MailParams = @{
    From = 'noreply@mydomain.domain.com'
    To = 'tommymaynard@mydomain.domain.com'
    Subject = 'Using Send-MailMessage and Splatting'
    Body = "This email sent from $env:USERNAME."
    SmtpServer = 'smtp.mydomain.domain.edu'
}

Send-MailMessage @MailParams

Bonus: If you have more parameters to add to a command, and they’re not included in the hash table (for whatever reason), you can still add them to the command.

Send-MailMessage @MailParams -Attachments 'C:\file.txt'

Second Bonus: What could be done instead of adding a separate parameter and parameter value to the command, as we saw in the above Bonus section, is adding another key-value pair to our hash table using the .Add() method.

$MailParams.Add('Attachments','C:\File.txt')

$MailParams

Name              Value
----              -----
Attachments       C:\File.txt
SmtpServer        smtp.mydomain.domain.com
Subject           Using Send-MailMessage and Splatting
Body              This email sent from tommymaynard.
From              noreply@mydomain.domain.com
To                tommymaynard@mydomain.domain.com

Send-MailMessage @MailParams

That’s it. Enjoy your Monday.

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