Execute remote PS command properly - powershell

Question

I'm trying to change passwords on more than 1000 hosts running windows server 2008/2012. They assigned to different domains, so I connect to them via their IP, all of them have PowerShell remoting open.
Stuck at my script implementation. For now I just want to connect to single host and change the password of the user or admin whatever.
Here is the code I use
$username = "UserWhose Password I want to change"
$password = ConvertTo-SecureString "users old password" -AsPlainText -Force
$cred = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $username, $password
$serverNameOrIp = "host ip address here"
$s = New-PSSession -ComputerName $serverNameOrIp -Authentication default -Credential $cred
#invoke the scriptblock remotely
$sb = {
"[ADSI]`$Admin=`"WinNT://$env:COMPUTERNAME/$env:USERNAME`""
"`$Admin.SetPassword(`"Users new password`")"
}
Invoke-Command -Session $s -ScriptBlock $sb
Remove-PSSession $s
Now, the console output I get:
PS C:\> ./script
[ADSI]$Admin="WinNT://WIN-TA49U0TR9GT/Administrator"
$Admin.SetPassword("Users new password")
PS C:\>
"WinNT://WIN-TA49U0TR9GT/Administrator" belongs to remote host, my local computername and a username are different.
I'm not getting any error or proper output here. The password isn't changing. If I try to run these commands manually on any host - it works.
Any suggestions? Maybe a working solutions?

Answer 1

You define the commands you want to run on the remote host as strings inside a scriptblock. When you invoke the scriptblock on the remote host it does what PowerShell does with all bare strings: echo them.
Remove the outer quoting and escaping and the code should work as you expect:
$sb = {
[ADSI]$Admin = "WinNT://$env:COMPUTERNAME/$env:USERNAME"
$Admin.SetPassword("Users new password")
}
The scriptblock already prevents variables from being expanded in the current context.

Answer 2

Posting complete working script, that accept console arguments, connect to specified host and change the user password.
ARGS = IP USERNAME OLDPASS NEWPASS
Hope this will help somebody
$serverNameOrIp = $args[0]
$username = $args[1]
$password = ConvertTo-SecureString -String $args[2] -AsPlainText -Force
$newPassword = $args[3]
$cred = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $username, $password
$s = New-PSSession -ComputerName $serverNameOrIp -Authentication default -Credential $cred
$sb = {
param($newPassword)
[ADSI]$Admin = "WinNT://$env:COMPUTERNAME/$env:USERNAME"
$Admin.SetPassword($newPassword)
}
Invoke-Command -Session $s -ScriptBlock $sb -args $newPassword
Remove-PSSession $s