{"id":4046,"date":"2013-03-09T00:01:00","date_gmt":"2013-03-09T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2013\/03\/09\/weekend-scripter-use-powershell-to-find-dynamic-parameters\/"},"modified":"2013-03-09T00:01:00","modified_gmt":"2013-03-09T00:01:00","slug":"weekend-scripter-use-powershell-to-find-dynamic-parameters","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/weekend-scripter-use-powershell-to-find-dynamic-parameters\/","title":{"rendered":"Weekend Scripter: Use PowerShell to Find Dynamic Parameters"},"content":{"rendered":"

Summary<\/strong>: Microsoft Scripting Guy, Ed Wilson, talks about using Windows PowerShell to discover dynamic parameters for his favorite cmdlets.<\/p>\n

Microsoft Scripting Guy, Ed Wilson, is here. I submitted my session for SQL Saturday in Atlanta, Georgia. To be honest, I was not going to do so because it is only two weeks prior to TechEd in New Orleans—but hey, there are a lot of cool people that attend SQL Saturday. I think we will probably have an all-day Windows PowerShell track at SQL Saturday in Atlanta. We did last year, and it was an absolute blast.  The question came up when I was on the PowerScripting podcast, and I have been mulling it over for a while. Finally, we decided to go. So the Scripting Wife and I will be at SQL Saturday in Atlanta (assuming they approve my session submission).<\/p>\n

Playing around with Get-Command<\/h2>\n

Anyway, I was playing around with Windows PowerShell this morning, and I decided to go back and read the Help file content for Get-Command.<\/strong> I ran across the –ArgumentList<\/strong> <\/em>parameter. I can use it to change the context for the Get-Command<\/strong> cmdlet. Cool.   <\/em><\/p>\n

Note<\/strong>   I am constantly reading over the Help content for Windows PowerShell because I simply cannot remember everything about everything. There is a difference between reading content when looking for an answer to a particular problem and simply grazing. <\/em>When I am looking for a specific answer, I find the answer and I leave to go solve my problem. When I am grazing, <\/em>I take my time and sample a bit of everything. I believe both types of reading are necessary.<\/p>\n

OK, so I use the Get-Command<\/strong> cmdlet and the –ArgumentList<\/strong> <\/em>parameter to display the definition of the command. Unfortunately, the first attempt does not work too well as shown here.<\/p>\n

PS C:\\> Get-Command Get-ChildItem -ArgumentList cert: | select definition<\/p>\n

 <\/p>\n

Definition<\/p>\n

———-<\/p>\n

…<\/p>\n

No problem; I know how to deal with this issue. I need to expand the object that is contained in the property. To do this, I use the Select-Object<\/strong> cmdlet and choose the –ExpandProperty<\/strong> <\/em>parameter. This results in a nice display of the parameter sets that are available when using the Get-Command<\/strong> cmdlet. These results are shown here.<\/p>\n

PS C:\\> Get-Command Get-ChildItem -ArgumentList cert: | select -expand definition<\/p>\n

 <\/p>\n

Get-ChildItem [[-Path] <string[]>] [[-Filter] <string>] [-Include <string[]>] [-Excl<\/p>\n

ude <string[]>] [-Recurse] [-Force] [-Name] [-UseTransaction] [-CodeSigningCert] [-S<\/p>\n

SLServerAuthentication] [-DnsName <DnsNameRepresentation>] [-Eku <string[]>] [-Expir<\/p>\n

ingInDays <int>] [<CommonParameters>]<\/p>\n

 <\/p>\n

Get-ChildItem [[-Filter] <string>] -LiteralPath <string[]> [-Include <string[]>] [-E<\/p>\n

xclude <string[]>] [-Recurse] [-Force] [-Name] [-UseTransaction] [-CodeSigningCert]<\/p>\n

[-SSLServerAuthentication] [-DnsName <DnsNameRepresentation>] [-Eku <string[]>] [-Ex<\/p>\n

piringInDays <int>] [<CommonParameters>]<\/p>\n

Well that is a command to keep in the back of my mind. I can get a nice display of a cmdlet parameter set on a per-provider basis by using the Get-Command<\/strong> cmdlet. Sweet!<\/p>\n

Now, I want to find only the parameters. To do this, I use the Select-Object<\/strong> cmdlet and choose parameters. The command and its output are shown here.<\/p>\n

PS C:\\> Get-Command Get-ChildItem -ArgumentList cert: | select parameters<\/p>\n

 <\/p>\n

Parameters<\/p>\n

———-<\/p>\n

{[Path, System.Management.Automation.ParameterMetadata], [LiteralPath, System.Man…<\/p>\n

Ah, ha. The Parameters<\/strong> property returns an object—actually, a collection of objects. So once again, I will send the result to the ExpandProperty<\/strong> parameter. This is shown here.<\/p>\n

PS C:\\> Get-Command Get-ChildItem -ArgumentList cert: | select -ExpandProperty parameters<\/p>\n

 <\/p>\n

Key                                        Value<\/p>\n

—                                        —–<\/p>\n

Path                                       System.Management.Automation.Parameter…<\/p>\n

LiteralPath                                System.Management.Automation.Parameter…<\/p>\n

Filter                                     System.Management.Automation.Parameter…<\/p>\n

Include                                    System.Management.Automation.Parameter…<\/p>\n

Exclude                                    System.Management.Automation.Parameter…<\/p>\n

Recurse                                    System.Management.Automation.Parameter…<\/p>\n

Force                                      System.Management.Automation.Parameter…<\/p>\n

Name                                       System.Management.Automation.Parameter…<\/p>\n

Verbose                                    System.Management.Automation.Parameter…<\/p>\n

Debug                                      System.Management.Automation.Parameter…<\/p>\n

ErrorAction                                System.Management.Automation.Parameter…<\/p>\n

WarningAction                              System.Management.Automation.Parameter…<\/p>\n

ErrorVariable                              System.Management.Automation.Parameter…<\/p>\n

WarningVariable                            System.Management.Automation.Parameter…<\/p>\n

OutVariable                                System.Management.Automation.Parameter…<\/p>\n

OutBuffer                                  System.Management.Automation.Parameter…<\/p>\n

UseTransaction                             System.Management.Automation.Parameter…<\/p>\n

CodeSigningCert                            System.Management.Automation.Parameter…<\/p>\n

SSLServerAuthentication                    System.Management.Automation.Parameter…<\/p>\n

DnsName                                    System.Management.Automation.Parameter…<\/p>\n

Eku                                        System.Management.Automation.Parameter…<\/p>\n

ExpiringInDays                             System.Management.Automation.Parameter…<\/p>\n

Now the information is contained in a generic dictionary object. This means there are a number of additional methods and properties to deal with. Actually, I am only interested in the Keys<\/strong> property. So, I use the group and dot technique, and select only the Keys<\/strong>. This is shown here.<\/p>\n

PS C:\\> (Get-Command Get-ChildItem -ArgumentList cert: | select -ExpandProperty parameters).keys<\/p>\n

Path<\/p>\n

LiteralPath<\/p>\n

Filter<\/p>\n

Include<\/p>\n

Exclude<\/p>\n

Recurse<\/p>\n

Force<\/p>\n

Name<\/p>\n

Verbose<\/p>\n

Debug<\/p>\n

ErrorAction<\/p>\n

WarningAction<\/p>\n

ErrorVariable<\/p>\n

WarningVariable<\/p>\n

OutVariable<\/p>\n

OutBuffer<\/p>\n

UseTransaction<\/p>\n

CodeSigningCert<\/p>\n

SSLServerAuthentication<\/p>\n

DnsName<\/p>\n

Eku<\/p>\n

ExpiringInDays<\/p>\n

Groovy. Now all I need to do is sort my list of properties so I can feed the results to Compare-Object<\/strong>. So, I back up a bit and I store the expanded parameters in a variable. I do this for the Certificate provider and for the FileSystem provider. These two commands are shown here.<\/p>\n

PS C:\\> $cert = Get-Command Get-ChildItem -ArgumentList cert: | select -ExpandProperty parameters<\/p>\n

PS C:\\> $file = Get-Command Get-ChildItem -ArgumentList c: | select -ExpandProperty parameters<\/p>\n

Now, I want to sort the keys, and store the sorted list of keys in a variable. The following two commands do this for me.<\/p>\n

PS C:\\> $certKeys = $cert.Keys | sort<\/p>\n

PS C:\\> $filekeys = $file.Keys | sort<\/p>\n

Now it is time to use the Compare-Object<\/strong> cmdlet to compare the two lists of provider-specific parameters for the Get-ChildItem<\/strong> cmdlet. This command is shown here.<\/p>\n

Compare-Object -ReferenceObject $filekeys -DifferenceObject $certKeys<\/p>\n

Following are the commands and the output associated with the commands.<\/p>\n

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

If I keep my comparisons consistent—that is, I use the FileSystem provider as my ReferenceObject<\/strong>, and I use the other providers for the DifferenceObject<\/strong>, the output will be consistent. The SideIndicator =><\/strong> will always point to new parameters added by the different PS Provider. Because the returned difference object is a PSCUSTOM object, it means that SideIndicator<\/strong> <\/em>is a NoteProperty<\/strong>, and I can use it in a Where-Object<\/strong> statement. The following command returns only parameters added by DifferenceObject<\/strong> (my collection of Certificate provider-specific parameters).<\/p>\n

PS C:\\> Compare-Object -ReferenceObject $filekeys -DifferenceObject $certKeys | ? sideindicator -eq ‘=>’<\/p>\n

 <\/p>\n

InputObject                                SideIndicator<\/p>\n

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

CodeSigningCert                            =><\/p>\n

DnsName                                    =><\/p>\n

Eku                                        =><\/p>\n

ExpiringInDays                             =><\/p>\n

SSLServerAuthentication                    =><\/p>\n

Comparing Get-ChildItem with the Registry provider<\/h2>\n

Any drive I pass to the –ArgumentList<\/strong> <\/em>parameter causes Get-Command<\/strong> to return provider-specific parameters. Therefore, I can use HKLM: as my drive to return Registry provider parameters. The following code illustrates the technique.<\/p>\n

$reg = Get-Command Get-ChildItem -ArgumentList hklm: | select –ExpandProperty parameters<\/p>\n

$file = Get-Command Get-ChildItem -ArgumentList c: | select -ExpandProperty parameters<\/p>\n

$regKeys = $reg.Keys | sort<\/p>\n

$filekeys = $file.Keys | sort<\/p>\n

 Compare-Object -ReferenceObject $filekeys -DifferenceObject $regKeys<\/p>\n

When I run the command, the following output displays.<\/p>\n

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

I can see from the previous output that there are no added parameters to Get-ChildItem<\/strong> when it is used on the registry drives. Instead, I see that a number of parameters are actually removed. This makes sense when reviewing the missing parameters: Attributes<\/strong>, Directory<\/strong>, File<\/strong>, Hidden<\/strong>, ReadOnly<\/strong>, and System<\/strong>. These are related to files and folders, not to registry keys.<\/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<\/strong> <\/p>\n","protected":false},"excerpt":{"rendered":"

Summary: Microsoft Scripting Guy, Ed Wilson, talks about using Windows PowerShell to discover dynamic parameters for his favorite cmdlets. Microsoft Scripting Guy, Ed Wilson, is here. I submitted my session for SQL Saturday in Atlanta, Georgia. To be honest, I was not going to do so because it is only two weeks prior to TechEd […]<\/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":[414,3,4,61,45],"class_list":["post-4046","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scripting","tag-providers","tag-scripting-guy","tag-scripting-techniques","tag-weekend-scripter","tag-windows-powershell"],"acf":[],"blog_post_summary":"

Summary: Microsoft Scripting Guy, Ed Wilson, talks about using Windows PowerShell to discover dynamic parameters for his favorite cmdlets. Microsoft Scripting Guy, Ed Wilson, is here. I submitted my session for SQL Saturday in Atlanta, Georgia. To be honest, I was not going to do so because it is only two weeks prior to TechEd […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/4046","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=4046"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/4046\/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=4046"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/categories?post=4046"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/tags?post=4046"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}