How to execute a powershell with '-command' argument in administration mode - powershell

Question

How can I run a powershell with -command parameters?
I tried adding '-Verb runAs', but I get a null valued expression.
powershell -Verb runAs -command "(Get-Date (Get-Process explorer).StartTime).ToString('yyyyMMdd')"
I open a powershell with admin right, the command
(Get-Date (Get-Process explorer).StartTime).ToString('yyyyMMdd')
return a right value. But when I start a powershell without admin right, I get a null value.
So I think the problem is the 'powershell -Verb runAs' does not run the command in admin mode.
Note: I logged in as ad administer when I tried this.

Answer 1

So elevating PowerShell's process can be done from within a script if you don't mind running a script instead of just executing a command. This will check if the process is already elevated, and if not it will re-launch the process with the RunAs verb so that it's running with elevated rights.
# Elevate UAC if not already running As Administrator
# Get the ID and security principal of the current user account
$myWindowsID=[System.Security.Principal.WindowsIdentity]::GetCurrent()
$myWindowsPrincipal=new-object System.Security.Principal.WindowsPrincipal($myWindowsID)
# Get the security principal for the Administrator role
$adminRole=[System.Security.Principal.WindowsBuiltInRole]::Administrator
# Check to see if we are currently running "as Administrator"
if (!$myWindowsPrincipal.IsInRole($adminRole))
{
# We are not running "as Administrator" - so relaunch as administrator
# Create an encoded string to re-launch the script bypassing execution policy
$Code = ". '$($myInvocation.MyCommand.Definition)'"
$Encoded = [Convert]::ToBase64String([Text.Encoding]::Unicode.GetBytes($code))
# Indicate that the process should be elevated
Start-Process PowerShell.exe -Verb RunAs -ArgumentList "-EncodedCommand",$Encoded
# Exit from the current, unelevated, process
exit
}
# End UACElevation
The code is a little convoluted with the encrypting of the command and what not, but I found that I sometimes had issues with execution policy blocking me if I didn't do it this way. This avoids execution policy blocking PowerShell from running scripts, since it technically isn't running a script, just an encoded command. That command just happens to be for it to run a script once the PSSession is started.