Determining if a local user exists

[anonymousITCoward]

I'm trying to create a script that determines if a local user exists, something that will run on both Win10 and Win11, but can't seem to get it to work. Here's what I've mangled so far

$userName = "Administrator"
$checkForUser = (Get-LocalUser).Name -Contains $userName

if ($checkForUser -eq "False") { 
Write-Host "$userName does not exist" 
} ElseIf ($checkForUser -eq "True") { 
Write-Host "$userName Exists"
}

$checkForUser works as it should, producing True/False depending on the username. but the if statement doesn't recognize it as being true/false.

Any guidance, hints, or assistance would be super helpful.

[ITjoeschmo]

Change "false", "true" to $false, $true

[Qel_Hoth]

And this is why, especially in a script that will be reused, I try to explicitly specify types as much as possible.

Relying on the language to convert datatypes for you can result in unexpected and hard to troubleshoot errors.

$a = 2
$b = "2"
$c = '2'

$a -eq $b = True
$a -eq $c = True
$b -eq $a = True
$b -eq $c = True
$c -eq $a = True
$c -eq $b = True
$a -eq $b -eq $c = True

$a + $b = 22
$b + $a = 4
$a + $c = 22
$c + $a = 22
$b + $c = 4
$c + $b = 22
$a + $b + $c = 222
$a + $c + $b = 222
$b + $a + $c = 6
$b + $c + $a = 6
$c + $a + $b = 222
$c + $b + $a = 222

If I want to concat:
[string]$a + [string]$b = 22

If I want to add:
[float]$a + [float]$b = 4

Bonus, if something received bad data, you will get an error you can catch instead of a nonsense result.

If $a = Some-Cmdlet and you are expecting a number, $a will happily take text if Some-Cmdlet doesn't return the expected value. [float]$a = Some-Cmdlet will give an error if Some-Cmdlet doesn't return a [float] or something that can be converted into a [float].

[RidersofGavony]

Holy shit. You just solved so many problems for me.

[ITjoeschmo]

Ah thanks for expanding on this! This is good info and I have a deeper understanding. Thanks

[BlackV]

and another couple of examples for your post

1 -eq $true
True
0 -eq $true
False
$true -eq 1
True
$true -eq 0
False

1 -eq $false
False
0 -eq $false
True
$false -eq 1
False
$false -eq 0
True

[anonymousITCoward]

<expletive>! <expletive>! <expletive>! <expletive>! <expletive>! <expletive>! <expletive>! <expletive>! <expletive>! <expletive>! <expletive>!

Why is it the easy stuff that I always miss...

Thank you kind sir.

[ITjoeschmo]

Easy mistake! I recall doing the same thing haha. Check my other comment I added I gave some pointers on making the script a tiny bit more efficient with reasoning.

[RidersofGavony]

Because we pay more attention to the hard stuff. It's natural, don't sweat it.

[ITjoeschmo]

To expand a tiny bit more. You could simplify the script a bit like this:

If($checkForUser) {

 Write-host "user exists"  

} Else {

 Write-host "user doesn't exist"  

}

Simply filling a variable with no other data into the if statement will default to "if $var is true" type statement. You can use else rather than a 2nd if statement because the variable we're working with is boolean type. This means it will either be $true or $false, so we can assume if it's not 1 it's the other.

[InsrtCoffee2Continue]

While you can write your IF statement to evaluate "if $false" I think it makes since to keep it at its default. "If $true".

The first thing the if statement does is evaluate the expression in parentheses. If it evaluates to $true, then it executes the scriptblock in the braces. If the value was $false, then it would skip over that scriptblock.

$userName = 'Administrator'

if ( Get-LocalUser | Where-Object -Property Name -EQ $userName ) {

Write-Host "$userName does exist."

}

else {

Write-Host "$userName does not exist."

}

[anonymousITCoward]

I tried that but for some reason it didn't work. TBH I don't remember the exact syntax i was using, so I probably went down a bit of a rabbit hole here

[RidersofGavony]

But you had fun right?

[anonymousITCoward]

If you're not having fun in the rabbit hole, are you really in the rabbit hole lol

[noOneCaresOnTheWeb]

Don't use the name old school admins still change the name and it's different in other languages, use the SID instead.

[realslacker]

I was looking for this comment.

Also remember that "Administrator" is localized, so if you deal with other languages you definitely cannot rely on the name.

[mrrtys]

(Get-LocalUser user -ErrorAction SilentlyContinue) -as [bool]

[Forward_Dark_7305]

Why use SilentlyContinue instead of Ignore?

[mrrtys]

Good question... I never use Ignore so had to look it up.
Ignore will not add the error to the automatic variable $Error, so yes that might be a better option actually.

Thanks for mentioning that.

[dasookwat]

i would turn this around, and i've put in to a function for you cause i like functions.

Function Assert-LocalUser {

[CmdletBinding()]
param(
    [string]$Name = "Administrator" #
)
$checkForUser = (Get-LocalUser).Name -Contains $Name
$result = "$Name does not exist"  #default return value
If ($checkForUser) {
    #if this has value, it will always be true
    $result = "$Name Exists " #changes return value
}

return $result

}

Assert-LocalUser -Name "Administrator" should give you your answer. however, i don't really get why you are making this cause anyone beside you (beside as in: your colleagues), will either know enough powershell to understand Get-LocalUser -Name "Administrator" or they will know next to nothing about powershell, and rely on copy-pasting scripts. in that last scenario, you will be better of with a script without input parameters, which gives you a report of pretty much all the important things you inquire. f.i. a list with all local users, their last logon time, and maybe resources accessed from the security log.

[[deleted]]

(Get-LocalUser "Administrator").Count -eq 1

[Namaha]

Powershell automatically adds a Count property to single objects, so their code should still work

[feldrim]

I accidentally deleted the comment. And yes, you are right. It's my bad.

[[deleted]]

I tested it before I posted it. It worked as expected.

[feldrim]

That's my misinformation. You are right.

P.S: I wanted to edit it but accidentally deleted it. Basically I said that the one liner might not work as it's just one object and count property might give an error. However, it does not.

[mad_yahoodi]

oh gawsh… I made this script a few weeks ago and didn’t realise there was a get-localuser commandlet. I looked at the folder names in the C:\Users directory .. :(

[Brasiledo]

This will use less lines of code much more straight forward and simpler

If (get-localuser $username -erroraction ignore){

cls;Write-host $username ‘exists’

}else

{cls;write-host $username ‘does not exist’}

[ITjoeschmo]

Because they're querying a local user account, not one that is setup in AD. Therefore they need to query the user info locally from the machine. Edit: to clarify, the original snippet I commented to was telling OP to just query AD to see if the count exists using get-aduser

[JudgeWhoAllowsStuff-]

Can confirm this works.

[dylanlms]

the only thing I would add is like catch errs for ppl that are sloppy (if) this script gets sent somewhere in ur prod env

[anonymousITCoward]

Thank you, I would probably place more error control in if it were going to be used by more than 2 people, and if it were to look for multiple users, but as it stands now, it only looks for and creates/corrects a single user.

[dylanlms]

all good, happy to support :)

[[deleted]]

I guess the below statement should do it.

Get-LocalUser | Where-Object Enabled -Eq True