I'm writing a PowerShell script finding directories with Get-ChildItem and passing them to sdelete. I would like to trial run it. I don't think sdelete has a -WhatIf flag. Is there any way I can achieve something similar?
You can implement the -WhatIf and -Confirm functionality by adding SupportShouldProcess to the CmdletBinding statement at the top of your function and a if ($pscmdlet.ShouldProcess(something) { } block to your code.
For example:
Function Remove-WithSDelete {
[CmdletBinding(SupportsShouldProcess,ConfirmImpact="High")]
Param ($File)
Process {
if ($pscmdlet.ShouldProcess($File)) {
& sdelete.exe $File
}
}
}
Usage:
PS C:\> Remove-WithSDelete c:\temp -WhatIf
What if: Performing the operation "Remove-WithSDelete" on target "c:\temp".
The ConfirmImpact part is optional and is used to define the level at which -Confirm is invoked automatically. If the impact level of the function is equal to or greater than your $ConfirmPreference level, -Confirm will be the default behaviour (without explicitly invoking it. You can force it off by doing -Confirm:$false). If you omit it your function Confirm Level is "Medium" by default. The default level of the $ConfirmPreference variable is "High".
Related
Hi guys its maybe a easy question for you but im newbie from powershell so can you pls help me?
In school I got an assignment where I needed to make a menu, a script that could search from service to status, and a script that could search from status to service, and it looks like this:
elseif ($menu -eq "2") {
$statusbank = (Get-Service).Status
$sstatuss = Read-Host "Bitte geben Sie ein Status ein z.B Running/Stopped"
if ($statusbank.Contains([string]$sstatuss)) {
$Information = (Get-Service | Where-Object {$_status -eq $sstatuss}).Name | format-list -property Name
Write-Host $Information
}
}
i really dont understand where my problem is.
It dosn't work: It doesn't do anything and then just ends the script
If i debug, i only see it will skip this, even they are a lot of true value in $statusbank :
if ($statusbank.Contains([string]$sstatuss)) {
Try using this instead:
elseif ($menu -eq "2")
{
$statusbank = Get-Service
$sstatuss = Read-Host "Bitte geben Sie ein Status ein z.B Running/Stopped"
if($sstatuss -match '^(Running|Stopped)$' -and $sstatuss -in $statusbank.Status)
{
$statusbank | Where-Object Status -EQ $sstatuss |
Format-Table -Property Name,Status
}
}
To complement Santiago Squarzon's helpful answer with an optimization:
# Prompt until a valid service status identifier is entered.
do {
try {
[System.ServiceProcess.ServiceControllerStatus] $sStatus =
Read-Host "Please specify the desired service status (e.g., Running or Stopped)"
break # A valid value was entered, exit the loop
} catch { }
Write-Warning "Unknown status; please specify one of: $([Enum]::GetNames([System.ServiceProcess.ServiceControllerStatus]))"
} while ($true)
# Now output the names of all services that are in the specified state, if any:
(Get-Service | Where-Object Status -eq $sStatus).Name
Casting the user input (which is always a string) to type [System.ServiceProcess.ServiceControllerStatus] (the type of the .Status property of the objects returned by Get-Service) is used to ensure that a valid service-status identifier was entered.
As for what you tried:
Leaving the inefficiency of calling Get-Service twice aside, your primary problem was the use of the .Contains() .NET array method (implemented via the IList interface):
.Contains() performs no on-demand type conversions, so looking for a string ($sstatuss) in your array of [System.ServiceProcess.ServiceControllerStatus] values ($statusbank) never succeeds.
By contrast, PowerShell's -contains operator does perform on-demand type conversions (as PowerShell generally does) and is notably also case-insensitive (as PowerShell generally is). The same applies to functionally equivalent, but operands-reversed -in operator.
To illustrate the difference:
# Sample array with [System.ServiceProcess.ServiceControllerStatus] elements.
$array = [System.ServiceProcess.ServiceControllerStatus]::Running,
[System.ServiceProcess.ServiceControllerStatus]::Stopped
# WRONG.
$array.Contains('running') # !! always $false with a [string] as input
# OK.
$array -contains 'running' # -> $true - on-demand type conversion
# from string to [System.ServiceProcess.ServiceControllerStatus]
In a nutshell: -contains is in effect using the -eq operator against each element behind the scenes, so the latter's automatic type conversions and case-insensitivity apply. See the bottom section of this answer for more information about -contains and -in.
Pitfall: Due to having the same name, there's potential for confusion with the .Contains() string method, which functions differently, however: it performs literal substring matching, and there is no direct operator equivalent in PowerShell for that - see this answer.
Also:
Format-* cmdlets output objects whose sole purpose is to provide formatting instructions to PowerShell's output-formatting system - see this answer. In short: only ever use Format-* cmdlets to format data for display, never for subsequent programmatic processing.
Write-Host is typically the wrong tool to use, unless the intent is to write to the display only, bypassing the success output stream and with it the ability to send output to other commands, capture it in a variable, or redirect it to a file. To output a value, use it by itself; e.g., $value instead of Write-Host $value (or use Write-Output $value, though that is rarely needed); see this answer
I have a script with many other scripts sourced. Each script sourced have a function.
One of my function need to stop according to a if statement. I tried continue, break, throw, evrything I saw on internet but either my main script completely end or my function continue.
Function code:
function AutoIndus-DeployUser($path){
$yaml=Get-Content $path | ?{!$_.StartsWith("#")}
$UsersPwd=$false
$user="";$password="";$groups="";$description=""; $options=""
$yaml | %{
if (($_-match "}") -and ($UsersPwd -eq $true)){Write-Host "function should stop"; return}
*actions*
}
}
Main script:
#functions list and link to extern scripts
Get-ChildItem -Path $PSScriptRoot\functions\ | %{$script=$_.Name; . $PSScriptRoot\functions\$script}
myfunction-doesnotwork
*some code*
Edit: I saw that return should stop the function without stoping the rest of the script, unfortunatly it does not stop anything at all:
Output:
Config file found
---
Changing user _usr-dba password
Changing user _usr-dba2 password
function should stop
Changing user _usr-dba3 password
function should stop
function should stop
function should stop
function should stop
function should stop
Disabling user DisableAccounts:{
Disable-LocalUser : User DisableAccounts:{ was not found.
At C:\Scripts\AWL-MS-AUTOMATION_AND_TOOLS\functions\AutoIndus-DisableAccount.ps1:25 char:13
+ Disable-LocalUser -Name $disable
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (DisableAccounts:{:String) [Disable-LocalUser], UserNotFoundException
+ FullyQualifiedErrorId : UserNotFound,Microsoft.PowerShell.Commands.DisableLocalUserCommand
Disabling user _usr-dba
To help you understanding, my script read a file and do actions according to each line it is reading. It start acting when it encounter something like User{ and should stop when it encounter }, _usr-dba3 being out of the curvy brackets it should not be treated. This way all my other function use the same one file. (changing user password and diasabling user are two different functions/sourced scripts)
Like you can see return does not do its job, maybe I'm missing one point in the use of return but I don't get it right now.
To prematurely exit out of a function before you reach the end of it, use
return
it works like break to where it will stop execution but instead of stopping the whole thread it will return back to the line below where you called the function.
Also keep in mind if your function has an output set return will return it back, for example with the function below:
function Get-ReturnValue()
{
$returnValue = "this is my output"
return $returnValue
}
if you called it like this:
$receivedReturnValue = Get-ReturnValue
then the variable receivedReturnValue would be loaded with the output of the function.
I needed a fast solution so I changed my functions, now there is no return/continue/... but a value that turn true. It is initialized to false and the action on each yaml lines are done when the value is equal to false.
Edit: So finally the issue was I didn't used function correctly. Return only works if you return into another function. So I putted almost the entire sctipt into a function that calls the function AutoIndus-DeployUser. Now it works perfectly !
This is my code:
if (FuncOne($valOne) -and FuncTwo($valTwo)) {
...
}
When both of those functions evaluate to $false, the code within the if statement still executes. Why is that? This also does not work as expected:
if (FuncOne($valOne) -eq $true -and FuncTwo($valTwo) -eq $true) {
...
}
When written this way, it works as expected.
$a = FuncOne($valOne)
$b = FuncTwo($valTwo)
if($a -and $b) {
...
}
What's going on?
This is a syntax issue.
The correct syntax for invoking functions in PowerShell is not:
functionName($arg1[,$arg2,$arg3])
but rather:
functionName [-parameterName1] $arg1 [[-parameterName2] $arg2]
Now, let's apply this to your if() sample expression:
FuncOne $valOne -and FuncTwo $valTwo
You'll notice that explicit parameter names (-ParameterName) and operators (-and) are completely indistinguishable - there's no way for the parser to tell whether -and is supposed to be interpreted as a parameter name or an operator. Additionally, the string literal FuncTwo can just as well be interpreted as a parameter argument, which is exactly what happens.
In order for the parser to know that you intend it to treat the expression as two separate expressions, force evaluation order with ():
if ((FuncOne $valOne) -and (FuncTwo $valTwo)) {
# They both returns a truthy value
}
You actualy need to place the function in parenthese in order to invoke it:
if ((FuncOne($valOne)) -and (FuncTwo($valTwo))) {
...
}
Is there a way to print debug messages to the console from a PowerShell function that returns a value?
Example:
function A
{
$output = 0
# Start of awesome algorithm
WriteDebug # Magic function that prints debug messages to the console
#...
# End of awesome algorithm
return $output
}
# Script body
$result = A
Write-Output "Result=" $result
Is there a PowerShell function that fits this description?
I'm aware of Write-Output and Write-*, but in all my tests using any of those functions inside a function like the one above will not write any debug messages. I'm also aware that just calling the function without using the returned value will indeed cause the function to write debug messages.
Sure, use the Write-Debug cmdlet to do so. Note that by default you will not see debug output. In order to see the debug output, set $DebugPreference to Continue (instead of SilentlyContinue). For simple functions I will usually do something like this:
function A ([switch]$Debug) {
if ($Debug) { $DebugPreference = 'Continue' }
Write-Debug "Debug message about something"
# Generate output
"Output something from function"
}
Note that I would not recommend using the form return $output. Functions output anything that isn't captured by a variable, redirected to a file (or Out-Null) or cast to [void]. If you need to return early from a function then by all means use return.
For advanced functions you can get debug functionality a bit more easily because PowerShell provides the ubiquitous parameters for you, including -Debug:
function A {
[CmdletBinding()]
param()
End {
$pscmdlet.WriteDebug("Debug message")
"Output something from cmdlet"
}
}
FYI, it's the [CmdletBinding()] attribute on the param() statement is what makes this an advanced function.
Also don't forget about Write-Verbose and $pscmdlet.WriteVerbose() if you just want a way to output additional information that isn't debug related.
Is there a shorter way to set multiple properties to the same value in Powershell in one command than this?
Example:
(gi "c:\test.txt").LastWriteTime = (gi "c:\test.txt").LastAccessTime = (gi "c:\test.txt").CreationTime = Get-date
I'm just curious if there is a way to shorten this syntax.
"CreationTime","LastWriteTime","LastAccessTime" |% {(gi test.txt).$_ = (get-date)}
I've used a slightly modified version of Mjolinor's answer to solve a problem I had of incorrect date on files that had just been downloaded from a remote source. I modified the code to make it cleaner to understand in case I have to come back to in the future (changed the short hand to full command names).
# Correct Access/Create/Write times on transferred files
ForEach( $File in $TransferList ) {
#("CreationTime","LastAccessTime","LastWriteTime") | ForEach {
$(Get-Item $File.Name).$_ = $File.Date
}
}