I have a powershell script which looks to make sure someone is running the script as an admin.
The variable $currentPrincipal returns true or false.
Here is the code:
$currentPrincipal = New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())
$currentPrincipal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
If ($currentPrincipal -eq $true) {
Write-host "yay"
}
Else {
Write-Host "boo"
}
But when running as an admin AND currentPrincipal is true, it still falls through to the else... here is the CLI which shows that:
PS C:\WINDOWS\system32> C:\Users\dogzilla\Desktop\SetSQLServerToManual.ps1
True
boo
My question is, what is the proper way to evaluate a boolean in powershell?
Your currently just calling WindowsPrincipal.IsInRole, which will output the Boolean result. Additionally, $currentPrincipal is of type System.Security.Principal.WindowsPrincipal, which is not a Boolean. I would ammend your code to store the result of IsInRole() as a variable and checking that instead.
$currentPrincipal = New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())
$checkRole = $currentPrincipal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
If ($checkRole -eq $true) {
Write-host "yay"
}
Else {
Write-Host "boo"
}
This is the way to test it:
if ( ($currentPrincipal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)) -eq $true )
I'm trying to make a loop for joining a Windows domain in PowerShell with usage of $?, which should return false/true if last command returned error or not.
This is what I got:
Add-Computer -DomainName "domainname.local" -Credential "admin"
$MaxAttempts = 0
do {
if ($? -like "false" -and $MaxAttempts -lt 5) {
$MaxAttempts += 1
Write-Host "Attempt" $MaxAttempts "out of 5"
Add-Computer -DomainName "domainname.local" -Credential "admin"
} else {
Write-Host "test"
}
Problem is when I have first command outside of that do/until loop it's returning true even when I get an error.
But when I add this command to do/until loop it returns false as expected but that way im running that command twice and that's not I want.
Can someone explain me this sorcery?
The automatic variable $? contains true or false depending on whether or not the previous PowerShell statement completed successfully. The last PowerShell statement before you check the value of $? inside the loop is $MaxAttempts = 0, which changes the value of $? to true (because the assignment operation succeeded), even if the Add-Computer statement before that failed.
I'd recommend adjusting your loop to something like this:
$MaxAttempts = 0
do {
Add-Computer -DomainName "domainname.local" -Credential "admin"
$success = $?
if (-not $success) {
$MaxAttempts++
}
} until ($success -or $MaxAttempts -ge 5) {
Background:
This is a parameter validation, its being run on powershell 2.0
there is no option to upgrade the WMF. My problem is...
if both parameters are empty, then display the Specify a parameter, if only P1 is empty display another if P2 is is empty then display another and if both are occupied, display another. I can't find a way to make it work right...
please help
Function checkParam
{
write-verbose "Parameter Validation"
If ("Lzu","Mlv","Irv" -Contains $MoveDBsTo)
{$param1=1}
else{$param1=0}
If (1,2,3 -Contains $SelectedPref)
{$param2=1}
else{$param2=0}
If ($param1 -and $param2 -eq 0)
{
$ErrorParams4 = #{
Message="SYNTAX ERROR: `n Specify a parameter"
Category="InvalidData"
}
Write-error #ErrorParams4
$paramsEmpty=1
Exit
}
If ($param1 -eq 0 -and $param2 -ne 1)
{
$ErrorParams1 = #{
Message="SYNTAX ERROR: `n Check syntax: -MoveDBsto [Lzu, Mlv, Irv]"
Category="InvalidData"
}
$param1=2
Write-error #ErrorParams1
Exit
}
If ($param2 -eq 0 -and $param1 -ne 1)
{
$ErrorParams2 = #{
Message="SYNTAX ERROR: `n Check syntax: -SelectedPref [1,2,3]"
Category="InvalidData"
}
$param2=2
Write-error #ErrorParams2
Exit
}
If ($param1 + $param2 -eq 2)
{
$ErrorParams3 = #{
Message="SYNTAX ERROR: `n Specify only one parameter"
Category="InvalidData"
}
Write-error #ErrorParams3
Exit
}
}
checkParam
I'm comparing 2 strings stored in a variable and validating them against a couple of conditions. See Code Below:
do
{
Write-Host -ForegroundColor 'Yellow' "Enter Users Password `nMust be 8 or more characters long and contain a UPPER case character and a Digit."
$Password = Read-Host "First time" -AsSecureString
$Passcheck = Read-Host "And again" -AsSecureString
$PassConvertFirst = [System.Runtime.InteropServices.Marshal]::SecureStringtoBSTR($Password) ; $PlainPass1 = [system.Runtime.InteropServices.Marshal]::PtrToStringAuto($passconvertfirst)
$PassConvertSecond = [System.Runtime.InteropServices.Marshal]::SecureStringtoBSTR($Passcheck) ; $PlainPass2 = [system.Runtime.InteropServices.Marshal]::PtrToStringAuto($Passconvertsecond)
if ($PlainPass1 -Contains $PlainPass2 -and $PlainPass1.Length -ge 8 -or $PlainPass2.Length -ge 8)
{
$PassCheckBreak = $false
$PlainPassword = $PlainPass2
}
else
{
Write-Warning "Passwords don't match, Try again.."
$PassCheckBreak = $true
}
}
while ($PassCheckBreak)
While this works 99.99% of the time i'm coming across a weird error when I try and compare this:
P4ssw0rd with P4ssword
Using the code above this gets validated as true! which makes no sense as if I try validating
W0rd with word
It fails validation.
I've tried changing to a comparative operator and I'm still getting the same issue.
Any thoughts or ideas?
Many Thanks,
Nigel Tatschner
The problem is within the if statement.
Let's have a closer look:
$PlainPass1 -Contains $PlainPass2 -and $PlainPass1.Length -ge 8 -or $PlainPass2.Length -ge 8
Evaluate each comparision:
$PlainPass1 -Contains $PlainPass2 # False
$PlainPass1.Length -ge 8 # True
$PlainPass2.Length -ge 8 #true
Thus the outcome is:
$false -and $true -or $true
Anything -or $true is true. Lesson: mind the binding order. When in doubt, use parenthesis.
I would like to find all directories at the top level from the location of the script that are stored in subversion.
In C# it would be something like this
Directory.GetDirectories(".")
.Where(d=>Directories.GetDirectories(d)
.Any(x => x == "_svn" || ".svn"));
I'm having a bit of difficulty finding the equivalent of "Any()" in PowerShell, and I don't want to go through the awkwardness of calling the extension method.
So far I've got this:
Get-ChildItem | ? {$_.PsIsContainer} | Get-ChildItem -force | ? {$_.PsIsContainer -and $_.Name -eq "_svn" -or $_.Name -eq ".svn"
This finds me the svn directories themselves, but not their parent directories - which is what I want. Bonus points if you can tell me why adding
| Select-Object {$_.Directory}
to the end of that command list simply displays a sequence of blank lines.
To answer the immediate question with a PowerShell v3+ solution:
(Get-ChildItem -Force -Directory -Recurse -Depth 2 -Include '_svn', '.svn').Parent.FullName
-Directory limits the matches to directories, -Recurse -Depth 2 recurses up to three levels (children, grandchildren, and great-grandchildren), Include allows specifying multiple (filename-component) filters, and .Parent.FullName returns the full path of the parent dirs. of the matching dirs., using member-access enumeration (implicitly accessing a collection's elements' properties).
As for the bonus question: select-object {$_.Directory} does not work,
because the \[System.IO.DirectoryInfo\] instances returned by Get-ChildItem have no .Directory property, only a .Parent property; Select-Object -ExpandProperty Parent should have been used.
In addition to only returning the property value of interest, -ExpandProperty also enforces the existence of the property. By contrast, Select-Object {$_.Directory} returns a custom object with a property literally named $_.Directory, whose value is $null, given that the input objects have no .Directory property; these $null values print as empty lines in the console.
As for the more general question about a PowerShell equivalent to LINQ's .Any() method, which indicates [with a Boolean result] whether a given enumerable (collection) has any elements at all / any elements satisfying a given condition:
Natively, PowerShell offers no such equivalent, but the behavior can be emulated:
Using the PowerShell v4+ intrinsic.Where() method:
Caveat: This requires collecting the entire input collection in memory first, which can be problematic with large collections and/or long-running input commands.
(...).Where({ $_ ... }, 'First').Count -gt 0
... represents the command of interest, and $_ ... the condition of interest, applied to each input object, where PowerShell's automatic $_ variable refers to the input object at hand; argument 'First' ensures that the method returns once the first match has been found.
For example:
# See if there's at least one value > 1
PS> (1, 2, 3).Where({ $_ -gt 1 }, 'First').Count -gt 0
True
Using the pipeline: Testing whether a command produced at least one output object [matching a condition]:
The advantage of a pipeline-based solution is that it can act on a command's output one by one, as it is being produced, without needing to collect the entire output in memory first.
If you don't mind that all objects are enumerated - even if you only care if there is at least one - use Paolo Tedesco's helpful extension to JaredPar's helpful answer.
The down-side of this approach is that you always have to wait for a (potentially long-running) command to finish producing all output objects, even though - logically - the determination whether there are any output objects can be made as soon as the first object is received.
If you want to exit the pipeline as soon as one [matching] object has been encountered, you have two options:
[Ad-hoc: Easy to understand, but cumbersome to implement]
Enclose the pipeline in a dummy loop and use break to break out of the pipeline and that loop (... represents the command whose output to test, and $_ ... match the condition):
# Exit on first input object.
[bool] $haveAny = do { ... | % { $true; break } } while ($false)
# Exit on first input object that matches a condition.
[bool] $haveAny = do { ... | % { if ($_ ...) { $true ; break } } } while ($false)
[Use a PowerShell v3+ self-contained utility function that is nontrivial to implement]
See the implementation of function Test-Any below.
It can be added to scripts or, for use in interactive sessions, to your $PROFILE file.
PowerShell v3+: Optimized utility function Test-Any
The function is nontrivial, because as of PowerShell (Core) v7.2.x, there is no direct way to exit a pipeline prematurely, so a workaround based on .NET reflection and a private type is currently necessary.
If you agree that there should be such a feature, take part in the conversation in GitHub issue #3821.
#requires -version 3
Function Test-Any {
[CmdletBinding()]
param(
[ScriptBlock] $Filter,
[Parameter(ValueFromPipeline = $true)] $InputObject
)
process {
if (-not $Filter -or (Foreach-Object $Filter -InputObject $InputObject)) {
$true # Signal that at least 1 [matching] object was found
# Now that we have our result, stop the upstream commands in the
# pipeline so that they don't create more, no-longer-needed input.
(Add-Type -Passthru -TypeDefinition '
using System.Management.Automation;
namespace net.same2u.PowerShell {
public static class CustomPipelineStopper {
public static void Stop(Cmdlet cmdlet) {
throw (System.Exception) System.Activator.CreateInstance(typeof(Cmdlet).Assembly.GetType("System.Management.Automation.StopUpstreamCommandsException"), cmdlet);
}
}
}')::Stop($PSCmdlet)
}
}
end { $false }
}
if (-not $Filter -or (Foreach-Object $Filter -InputObject $InputObject)) defaults to true if $Filter wasn't specified, and otherwise evaluates the filter (script block) with the object at hand.
The use of ForEach-Object to evaluate the filter script block ensures that $_ binds to the current pipeline object in all scenarios, as demonstrated in PetSerAl's helpful answer here.
The (Add-Type ... statement uses an ad-hoc type created with C# code that uses reflection to throw the same exception that Select-Object -First (PowerShell v3+) uses internally to stop the pipeline, namely [System.Management.Automation.StopUpstreamCommandsException], which as of PowerShell v5 is still a private type.
Background here:
http://powershell.com/cs/blogs/tobias/archive/2010/01/01/cancelling-a-pipeline.aspx
A big thank-you to PetSerAl for contributing this code in the comments.
Examples:
PS> #() | Test-Any false
PS> Get-EventLog Application | Test-Any # should return *right away* true
PS> 1, 2, 3 | Test-Any { $_ -gt 1 } # see if any object is > 1 true
Background information
JaredPar's helpful answer and Paolo Tedesco's helpful extension fall short in one respect: they don't exit the pipeline once a match has been found, which can be an important optimization.
Sadly, even as of PowerShell v5, there is no direct way to exit a pipeline prematurely.
If you agree that there should be such a feature, take part in the conversation in GitHub issue #3821.
A naïve optimization of JaredPar's answer actually shortens the code:
# IMPORTANT: ONLY EVER USE THIS INSIDE A PURPOSE-BUILT DUMMY LOOP (see below)
function Test-Any() { process { $true; break } end { $false } }
The process block is only entered if there's at least one element in the pipeline.
Small caveat: By design, if there's no pipeline at all, the process block is still entered, with $_ set to $null, so calling Test-Any outside of a pipeline unhelpfully returns $true. To distinguish between between $null | Test-Any and Test-Any, check $MyInvocation.ExpectingInput, which is $true only in a pipeline: Thanks, PetSerAl
function Test-Any() { process { $MyInvocation.ExpectingInput; break } end { $false } }
$true, written to the output stream, signals that at least one object was found.
break then terminates the pipeline and thus prevents superfluous processing of additional objects. HOWEVER, IT ALSO EXITS ANY ENCLOSING LOOP - break is NOT designed to exit a PIPELINEThanks, PetSerAl
.
If there were a command to exit the pipeline, this is where it would go.
Note that return would simply move on to the next input object.
Since the process block unconditionally executes break, the end block is only reached if the process block was never entered, which implies an empty pipeline, so $false is written to the output stream to signal that.
Unfortunately there is no equivalent in PowerShell. I wrote a blog post about this with a suggestion for a general purpose Test-Any function / filter.
function Test-Any() {
begin {
$any = $false
}
process {
$any = $true
}
end {
$any
}
}
Blog post: Is there anything in that pipeline?
A variation on #JaredPar's answer, to incorporate the test in the Test-Any filter:
function Test-Any {
[CmdletBinding()]
param($EvaluateCondition,
[Parameter(ValueFromPipeline = $true)] $ObjectToTest)
begin {
$any = $false
}
process {
if (-not $any -and (& $EvaluateCondition $ObjectToTest)) {
$any = $true
}
}
end {
$any
}
}
Now I can write "any" tests like
> 1..4 | Test-Any { $_ -gt 3 }
True
> 1..4 | Test-Any { $_ -gt 5 }
False
You can use the original LINQ Any:
[Linq.Enumerable]::Any($list)
It's actually quite simple - just select first $true (formatted for clarity):
[bool] ($source `
| foreach { [bool] (<predicate>) } `
| where { $_ } `
| select -first 1)
Alternative way:
($source `
| where { <predicate> } `
| foreach { $true } `
| select -first 1)
My approach now was:
gci -r -force `
| ? { $_.PSIsContainer -and $_.Name -match "^[._]svn$" } `
| select Parent -Unique
The reason why
select-object {$_.Directory}
doesn't return anything useful is that there is no such property on a DirectoryInfo object. At least not in my PowerShell.
To elaborate on your own answer: PowerShell can treat most non-empty collections as $true, so you can simply do:
$svnDirs = gci `
| ? {$_.PsIsContainer} `
| ? {
gci $_.Name -Force `
| ? {$_.PSIsContainer -and ($_.Name -eq "_svn" -or $_.Name -eq ".svn") }
}
I ended up doing it with a count:
$directoryContainsSvn = {
(Get-ChildItem $_.Name -force | ? {$_.PsIsContainer -and $_.Name -eq "_svn" -or $_.Name -eq ".svn"} | Measure-Object).Count -eq 1
}
$svnDirs = Get-ChildItem | ? {$_.PsIsContainer} | ? $directoryContainsSvn
You can tighten this up a bit:
gci -fo | ?{$_.PSIsContainer -and `
(gci $_ -r -fo | ?{$_.PSIsContainer -and $_ -match '[_.]svn$'})}
Note - passing $__.Name to the nested gci is unnecessary. Passing it $_ is sufficent.
I recommend the following solution:
<#
.SYNOPSIS
Tests if any object in an array matches the expression
.EXAMPLE
#( "red", "blue" ) | Where-Any { $_ -eq "blue" } | Write-Host
#>
function Where-Any
{
[CmdletBinding()]
param(
[Parameter(Mandatory = $True)]
$Condition,
[Parameter(Mandatory = $True, ValueFromPipeline = $True)]
$Item
)
begin {
[bool]$isMatch = $False
}
process {
if (& $Condition $Item) {
[bool]$isMatch = $true
}
}
end {
Write-Output $isMatch
}
}
# optional alias
New-Alias any Where-Any
This is the best method that I found so far (does not iterate over all elements if already found a true, and does not break the pipeline):
From LINQ Any() equivalent in PowerShell
It’s possible to use a built-in $input variable that contains the whole pipeline in a scope of function.
So, the desired code could look like the following:
function Test-Any([scriptBlock] $scriptBlock = {$true}, [scriptBlock] $debugOut = $null)
{
if ($debugOut)
{
Write-Host(“{0} | % {{{1}}}” -f $input, $scriptBlock)
}
$_ret = $false;
$_input = ($input -as [Collections.IEnumerator])
if ($_input)
{
while ($_input.MoveNext())
{
$_ = $_input.Current;
Write-Host $_
if ($debugOut)
{
Write-Host(“Tested: [{0}]” -f (&$debugOut))
}
if (&$scriptBlock)
{
if ($debugOut)
{
Write-Host(“Matched: [{0}]” -f (&$debugOut))
}
$_ret = $true
break
}
}
}
$_ret
}
I think that the best answer here is the function proposed by #JaredPar, but if you like one-liners as I do I'd like to propose following Any one-liner:
# Any item is greater than 5
$result = $arr | %{ $match = $false }{ $match = $match -or $_ -gt 5 }{ $match }
%{ $match = $false }{ $match = $match -or YOUR_CONDITION }{ $match } checks that at least one item match condition.
One note - usually the Any operation evaluates the array until it finds the first item matching the condition. But this code evaluates all items.
Just to mention, you can easily adjust it to become All one-liner:
# All items are greater than zero
$result = $arr | %{ $match = $false }{ $match = $match -and $_ -gt 0 }{ $match }
%{ $match = $false }{ $match = $match -and YOUR_CONDITION }{ $match } checks that all items match condition.
Notice, that to check Any you need -or and to check All you need -and.
I took a more linq-style approach.
I know this question is probably super old. I used this to accomplish my needs:
PS> $searchData = "unn"
PS> $StringData = #("unn", "dew", "tri", "peswar", "pymp")
PS> $delegate = [Func[string,bool]]{ param($d); return $d -eq $searchData }
PS> [Linq.Enumerable]::Any([string[]]$StringData, $delegate)
Taken from here:
https://www.red-gate.com/simple-talk/dotnet/net-framework/high-performance-powershell-linq/#post-71022-_Toc482783751