{"id":249,"date":"2008-01-28T19:45:58","date_gmt":"2008-01-29T03:45:58","guid":{"rendered":"http:\/\/testblog.sapien.com\/index.php\/2008\/01\/28\/got-powershell-revisited\/"},"modified":"2008-07-08T02:15:57","modified_gmt":"2008-07-08T10:15:57","slug":"got-powershell-revisited","status":"publish","type":"post","link":"https:\/\/dev.sapien.com\/blog\/2008\/01\/28\/got-powershell-revisited\/","title":{"rendered":"Got-PowerShell Revisited"},"content":{"rendered":"

Last week<\/a> I showed a PowerShell function that used WMI to remotely query a machine to determine if PowerShell was installed. Well, like most things Microsoft there’s often more than one way to accomplish a task. Here is a different version of essentially the same function. This version, however, uses the .NET framework and the Microsoft.Win32.Registry class:<\/p>\n

Function Get-PowerShellInstall {
\nParam ([string]$computer="localhost") <\/font><\/p>\n

$ErrorActionPreference="SilentlyContinue"
\n$DebugPreference="SilentlyContinue" <\/font><\/p>\n

#provide some traps to handle connection errors
\nTrap [system.IO.IOException] {
\nWrite-Warning "Failed to connect to $computer"
\nWrite-Debug "IOException with $computer"
\n$script:failed=$True
\ncontinue
\n} <\/font><\/p>\n

Trap [system.UnauthorizedAccessException] {
\nWrite-Warning "Access violation on $computer"
\nWrite-Debug "UnauthorizedAccessException on $computer"
\n$script:denied=$True
\ncontinue
\n} <\/font><\/p>\n

#The registry class doesn’t accept localhost as
\n#a computer name so if passed, get the actual
\n#computer name <\/font><\/p>\n

if ($computer -match "localhost") {
\n$computer = $env:computername
\n} <\/font><\/p>\n

$computer=$computer.ToUpper()
\nWrite-Debug "Connecting to $computer" <\/font><\/p>\n

$regbase=[Microsoft.Win32.RegistryKey]::`
\nOpenRemoteBaseKey([Microsoft.Win32.RegistryHive]::`
\nLocalMachine,$computer) <\/font><\/p>\n

Write-Debug "Continuing with function"
\nIf ($script:denied) {
\nWrite-Debug "access denied"
\nRemove-Variable denied -Scope Script
\nReturn
\n} <\/font><\/p>\n

If ($script:failed) {
\nWrite-Debug "failed to connect"
\nRemove-Variable failed -Scope Script
\nReturn
\n} <\/font><\/p>\n

#bail out if the OpenRemoteBaseKey method failed.
\nif (!$regbase) {
\nWrite-Debug "regbase not found"
\nreturn
\n} <\/font><\/p>\n

$basePath="software\\microsoft\\powershell\\1"
\n$ShellPath="shellids\\Microsoft.PowerShell"
\n$EnginePath="PowerShellEngine" <\/font><\/p>\n

Write-Debug "basepath=$basepath"
\nWrite-Debug "shellpath=$shellpath"
\nWrite-Debug "enginepath=$enginepath" <\/font><\/p>\n

Write-Debug "Opening (Join-Path $basePath $ShellPath)"
\n$regkey=$regbase.opensubkey((Join-Path $basePath $ShellPath)) <\/font><\/p>\n

if ($regkey) {
\nWrite-Debug "`$regkey is found on $computer"
\n$InstallPath=$regkey.GetValue("path")
\nWrite-Debug "Install path is $InstallPath"
\n#only get other values if able to get a value for $InstallPath
\nif ($InstallPath) {
\n$Installed=$True
\n$ExecutionPolicy=$regkey.GetValue("ExecutionPolicy")
\nWrite-Debug "found execution policy of $ExecutionPolicy"
\n#if ExecutionPolicy key is missing then assume Restricted
\nif (-not $ExecutionPolicy) {
\nWrite-Debug "Execution policy is missing"
\n$ExecutionPolicy="Restricted"
\n}
\n$regkey=$regbase.opensubkey((Join-Path $basePath $EnginePath))
\n$PowerShellVersion=$Regkey.GetValue("PowerShellVersion")
\nWrite-Debug "Found version of $PowerShellVersion"
\n$RunTimeVersion=$RegKey.GetValue("RunTimeVersion")
\nWrite-Debug "Found RunTimeVersion of $RunTimeVersion"
\n} #end If ($InstallPath)
\n}
\nelse {
\nWrite-Debug "`$regkey is NOT found on $computer "
\n$InstallPath=$Null
\n$Installed=$False
\n$ExecutionPolicy=$Null
\n$PowerShellVersion=$Null
\n$RunTimeVersion=$Null
\n} #end if ($regkey) <\/font><\/p>\n

Write-Debug "Creating custom object" <\/font><\/p>\n

$obj=New-Object PSObject
\n$obj | Add-Member -MemberType NoteProperty -Name "Computer" -Value $computer.ToUpper()
\n$obj | Add-Member -MemberType NoteProperty -Name "Installed" -Value $Installed
\n$obj | Add-Member -MemberType NoteProperty -Name "InstallPath" -Value $InstallPath
\n$obj | Add-Member -MemberType NoteProperty -Name "ExecutionPolicy" -Value $ExecutionPolicy
\n$obj | Add-Member -MemberType NoteProperty -Name "Version" -Value $PowerShellVersion
\n$obj | Add-Member -MemberType NoteProperty -Name "RunTimeVersion" -Value $RunTimeVersion <\/font><\/p>\n

write $obj
\nWrite-Debug "end of function"
\n}<\/font><\/p>\n

Again, don’t try to copy and paste. Grab the attached file instead. There are some noticeable differences between this version and the one using WMI. This version has a few traps to handle different types of connection errors. If you attempt to connect to a machine that isn’t available, the function uses the Warning pipeline to display a message. You’ll get a slightly different error message if there is a permissions problem. By using Write-Warning, assuming your shell’s $WarningPreference is still set the to default of Continue, you can run an expression like this:<\/p>\n

get-content c:\\servers.txt | foreach-object {get-powerShellinstall $_} | Select computer,Installed,Version | convertto-html | out-file c:\\test\\psh.html<\/font><\/p>\n

You can still see the warnings, but it they won’t be a part of the end result. I’ve added a few other sample usages in the attached file.<\/p>\n

I’ve also added some debug lines for tracing code execution. If you need to troubleshoot, change $debugpreference in the function to Continue and you’ll the debug lines written to the debug pipeline.<\/p>\n

One last major advantage to this version is that even though it doesn’t explicitly allow for alternate credentials, as long as a I have a secure channel to the remote computer, this script will work. What this means is I can map a drive to a server like this:<\/p>\n

net use * <\/font>\\server01\\c$<\/font><\/a> \/user:mydom\\auser <\/font>P@ssw0rd<\/font><\/a><\/p>\n

Once the drive is mapped, I can use the PowerShell function:<\/p>\n

Get-powershellinstall server01<\/font><\/p>\n

And it will work.<\/p>\n

If you come up with any interesting ways to use this function, please let me know.<\/p>\n

 <\/p>\n

Technorati Tags: <\/span>PowerShell<\/span><\/a>, <\/span>Registry<\/span><\/a>, <\/span>Win32<\/span><\/a>, <\/span>.NET<\/span><\/a><\/div>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Last week I showed a PowerShell function that used WMI to remotely query a machine to determine if PowerShell was installed. Well, like most things Microsoft there’s often more than one way to accomplish a task. Here is a different version of essentially the same function. This version, however, uses the .NET framework and the Microsoft.Win32.Registry class.<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[25],"tags":[28,31,36,54,35],"class_list":["post-249","post","type-post","status-publish","format-standard","hentry","category-windows-powershell","tag-powershell","tag-registry","tag-remote","tag-win32","tag-wmi"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/posts\/249","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/comments?post=249"}],"version-history":[{"count":0,"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/posts\/249\/revisions"}],"wp:attachment":[{"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/media?parent=249"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/categories?post=249"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dev.sapien.com\/blog\/wp-json\/wp\/v2\/tags?post=249"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}