{"id":71902,"date":"2015-07-27T00:01:00","date_gmt":"2015-07-27T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2015\/07\/27\/describe-your-powershell-variables\/"},"modified":"2019-02-18T09:46:50","modified_gmt":"2019-02-18T16:46:50","slug":"describe-your-powershell-variables","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/describe-your-powershell-variables\/","title":{"rendered":"Describe Your PowerShell Variables"},"content":{"rendered":"

Summary<\/b>: Ed Wilson, Microsoft Scripting Guy, talks about adding a description to variables.<\/span><\/p>\n

Microsoft Scripting Guy, Ed Wilson, is here. There is a “water feature” outside that keeps running and running and running. It is a bit strange, and to be honest, it makes me think that it is raining all the time. In central Florida in the summer, it is generally a safe bet that it will rain, but even when the sun is outside, without a cloud in the sky, the giant frog keeps spitting water into a pond. I don’t get it. It is not relaxing like a Zen pond, and it does not keep bugs at bay like a real frog would do. It just sits there.<\/p>\n

Sometimes I run across things on my computer that are bit like that ceramic frog, and I just don’t get it. I see a user account and wonder, “Why was that created?” Or I see a group that causes the same question.<\/p>\n

On the network, it is even worse, because there are multiple admins, and often a bit of turnover, so no one knows why something was created. Unfortunately, the old technique of “delete it and see who complains” does not work for today’s fast-paced environments. I mean, who in their right mind wants to create additional work for themselves.<\/p>\n

And unfortunately, “see who complains” might not complain for several months—in which time you forget what you deleted in the first place. So it means hours of troubleshooting (because if I really knew the app in the first place, I would know what the "thing" I was getting ready to delete would do).<\/p>\n

Luckily, with Windows PowerShell, I can fix some of that.<\/p>\n

Add descriptions to global variables<\/h2>\n

In my profile last week, I added two variables that I want to always be available to me. These are global variables (meaning I can use them in functions, modules, and the like), and I really don’t want them changed. In fact, the reason I created them was so that I would have a consistent environment.<\/p>\n

But unfortunately, when I created them, I did not ensure any of that. To make matters worse, I did not even document why I was creating the variables in the first place.<\/p>\n

Luckily, I can easily fix that by adding various parameters of from the New-Variable<\/b> cmdlet. I am often asked why we have a New-Variable<\/b> cmdlet when I can create a variable by simply making an assignment to the variable, for example:<\/p>\n

$a = 1<\/p>\n

And why do we have the New-Variable<\/b> cmdlet when I can create a new variable by adding it to the variable drive like this:<\/p>\n

PS C:\\> New-Item -Name b -Value 2 -Path variable:<\/p>\n

Name                           Value<\/p>\n

—-                           —–<\/p>\n

b                              2<\/p>\n

PS C:\\> $b<\/p>\n

2<\/p>\n

Both of these techniques work fine if I am not concerned about adding things like a description, or scope, or whether it is Read-only. I can assign the additional properties to a variable by using the Set-Variable<\/b> cmdlet. As shown here, if I do not set these additional properties, the only the name and value are assigned:<\/p>\n

PS C:\\> $a = 1<\/p>\n

PS C:\\> Get-Variable a<\/p>\n

Name                           Value<\/p>\n

—-                           —–<\/p>\n

a                              1<\/p>\n

PS C:\\> Get-Variable a | fl *<\/p>\n

Name        : a<\/p>\n

Description :<\/p>\n

Value       : 1<\/p>\n

Visibility  : Public<\/p>\n

Module      :<\/p>\n

ModuleName  :<\/p>\n

Options     : None<\/p>\n

Attributes  : {}<\/p>\n

When I use Set-Variable<\/b> to add a description, I can pick it up with the Get-Variable<\/b> cmdlet:<\/p>\n

PS C:\\> Set-Variable a -Description "my variable"<\/p>\n

PS C:\\> Get-Variable a | select name, description<\/p>\n

Name                                                        Description<\/p>\n

—-                                                        ———–<\/p>\n

a                                                           my variable<\/p>\n

Note <\/b> When using Get-Variable<\/b> or Set-Variable<\/b>, I do not use the dollar sign ( $<\/b> ) in my variable name.<\/p>\n

Include the description and options<\/h2>\n

As a best practice, I should include the description and options for my variables when I create them in my profile. In this way, I can easily find them. In fact, if I use the same description or the same words in my description, I will be able to find my specific profile-created variables. Here are the changes I make to my two variables in my profile:<\/p>\n

#Variables<\/p>\n

New-Variable -Name doc -Value "$home\\documents" `<\/p>\n

   -Description "My documents library. Profile created" `<\/p>\n

   -Option ReadOnly -Scope "Global"<\/p>\n

if(!(Test-Path variable:backupHome))<\/p>\n

{<\/p>\n

 new-variable -name backupHome -value "$doc\\WindowsPowerShell\\profileBackup" `<\/p>\n

    -Description "Folder for profile backups. Profile created" `<\/p>\n

    -Option ReadOnly -Scope "Global"<\/p>\n

}<\/p>\n

When I close my Windows PowerShell console, and open it up again, the changes take effect. I can now find my profile-created variables easily. This is shown here:<\/p>\n

PS C:\\> (Get-Variable).where({$_.description -match 'profile created'})<\/p>\n

Name                           Value<\/p>\n

—-                           —–<\/p>\n

backupHome                     C:\\Users\\ed\\documents\\WindowsPowerShell\\profileBackup<\/p>\n

doc                            C:\\Users\\ed\\documents<\/p>\n

I can now pipe the output to the Format-List<\/b> cmdlet and see the additional information. This is shown in the following image:<\/p>\n

\"Image<\/a><\/p>\n

That is all there is to using a variable description. Join me tomorrow when I will talk more about Windows PowerShell profiles.<\/p>\n

I invite you to follow me on Twitter<\/a> and Facebook<\/a>. If you have any questions, send email to me at scripter@microsoft.com<\/a>, or post your questions on the Official Scripting Guys Forum<\/a>. See you tomorrow. Until then, peace.<\/p>\n

Ed Wilson, Microsoft Scripting Guy<\/b> <\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Summary: Ed Wilson, Microsoft Scripting Guy, talks about adding a description to variables. Microsoft Scripting Guy, Ed Wilson, is here. There is a “water feature” outside that keeps running and running and running. It is a bit strange, and to be honest, it makes me think that it is raining all the time. In central […]<\/p>\n","protected":false},"author":596,"featured_media":87096,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[51,144,3,4,605,45],"class_list":["post-71902","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scripting","tag-getting-started","tag-profiles","tag-scripting-guy","tag-scripting-techniques","tag-variables","tag-windows-powershell"],"acf":[],"blog_post_summary":"

Summary: Ed Wilson, Microsoft Scripting Guy, talks about adding a description to variables. Microsoft Scripting Guy, Ed Wilson, is here. There is a “water feature” outside that keeps running and running and running. It is a bit strange, and to be honest, it makes me think that it is raining all the time. In central […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/71902","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/users\/596"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/comments?post=71902"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/71902\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media\/87096"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media?parent=71902"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/categories?post=71902"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/tags?post=71902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}