Powershell Function Start-Proc

Andy Schneider — Fri, 22 Feb 2008 15:59:11 +0000

The gentlemen over at the Power Scripting Podcast recently posted a tip on how to start processes in Powershell.

I had run into the same problem they had. How do you pass in both an executable and its arguments to the Start method of a System.Diagnostics.Process object.

Something like this works fine in Powershell:

[System.Diagnostics.Process]::Start(“calc”)

But as soon as you try to pass in something like “ipconfig /all” the thing blows up.

Turns out you can pass in arguments a couple of ways. The Powerscripting guys noted that if you pass in the argument of the executable as a second argument to Start, it will work great.

[System.Diagnostics.Process]::Start(“ipconfig”,”all”)

However, there is another way if you want to get a little bit more fancy and do things like hide windows or redirect output from StdOut or StdErr.

You can use a System.Diagnostic.ProcessStartInfo object. Using get-member we can take a look at all the options we have for such a thing.

PS 124 >  $si = New-Object System.Diagnostics.ProcessStartInfo
PS 125 >  $si | gm  -type property | select Name
  
Name
----
Arguments
CreateNoWindow
Domain
EnvironmentVariables
ErrorDialog
ErrorDialogParentHandle
FileName
LoadUserProfile
Password
RedirectStandardError
RedirectStandardInput
RedirectStandardOutput
StandardErrorEncoding
StandardOutputEncoding
UserName
UseShellExecute
Verb
Verbs
WindowStyle
WorkingDirectory

Lots of goodness here that we can play with. Once you build up the ProcessStartInfo object, you pass that whole object in as the arg to the Start method of system.diagnostics.process.

I put together a quick function to show how this could be used more generically.

function Start-Proc  {
    param (
            [string]$exe = $(Throw "An executable must be specified"),
            [string]$arguments,
            [switch]$hidden,
            [switch]$waitforexit
            )    
    
    # Build Startinfo and set options according to parameters
    $startinfo = new-object System.Diagnostics.ProcessStartInfo 
    $startinfo.FileName = $exe
    $startinfo.Arguments = $arguments
    if ($hidden){
                $startinfo.WindowStyle = "Hidden"
                $startinfo.CreateNoWindow = $TRUE
                }
    $process = [System.Diagnostics.Process]::Start($startinfo)
    if ($waitforexit) {$process.WaitForExit()}
    
}
  
 Start-Proc calc
 Start-Proc calc -waitforexit
 Start-Proc -exe ipconfig -arguments /all
 Start-Proc ipconfig /all
 Start-Proc ipconfig /all -hidden

I used the alias Start-Proc so that it would not collide with the PSCX Cmdlet Start-Process.

They have done the same writing their CmdLet in C#, but with all kinds of options.

PS 130 >  gcm Start-Process | fl *
  
  
DLL              : C:\Program Files (x86)\PowerShell Community Extensions\Pscx.dll
Verb             : Start
Noun             : Process
HelpFile         : Pscx.dll-Help.xml
PSSnapIn         : Pscx
ImplementingType : Pscx.Commands.StartProcessCommand
ParameterSets    : {[[-Path] ] [[-Arguments] ] [-Verb ] [-WorkingDirectory ] [-Credential ] [-NoShellExecute] [-NoWindow]
                   [-WindowStyle ] [-LoadUserProfile] [-WaitTimeout ] [-Boost] [-Priority ] [-Verbose] [-Debug] [-Error
                   Action ] [-ErrorVariable ] [-OutVariable ] [-OutBuffer ] [-WhatIf] [-Confirm], [[-ScriptBlock] 
                   ] [-NoProfile] [-WorkingDirectory ] [-Credential ] [-NoShellExecute] [-NoWindow] [-WindowStyle ] [-LoadUser
                   Profile] [-WaitTimeout ] [-Boost] [-Priority ] [-Verbose] [-Debug] [-ErrorAction ] [-ErrorVariable 
                   ring>] [-OutVariable ] [-OutBuffer ] [-WhatIf] [-Confirm]}
Definition       : Start-Process [[-Path] ] [[-Arguments] ] [-Verb ] [-WorkingDirectory ] [-Credential ] [-NoShellExecute]
                    [-NoWindow] [-WindowStyle ] [-LoadUserProfile] [-WaitTimeout ] [-Boost] [-Priority ] [-Verbose] [-D
                   ebug] [-ErrorAction ] [-ErrorVariable ] [-OutVariable ] [-OutBuffer ] [-WhatIf] [-Confirm]
                   Start-Process [[-ScriptBlock] ] [-NoProfile] [-WorkingDirectory ] [-Credential ] [-NoShellExecute] [-NoWindow] [-W
                   indowStyle ] [-LoadUserProfile] [-WaitTimeout ] [-Boost] [-Priority ] [-Verbose] [-Debug] [-ErrorAct
                   ion ] [-ErrorVariable ] [-OutVariable ] [-OutBuffer ] [-WhatIf] [-Confirm]
  
Name             : Start-Process
CommandType      : Cmdlet
Visibility       : Public

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Powershell Function Start-Proc