PowerShell - Running Executables - TechNet Articles - United States (English)

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There are several different methods for running executables. How do you know which one to use for the job? Here is an outline of the methods with examples and general use.

Currently we've found there to be 9 distinctly different methods for running an executable.

1. Direct - Using the environment path or local folder (dot sourcing)
2. Invoke-Expression (IEX)
3. Invoke-Command (ICM)
4. Invoke-Item (II)
5. The Call Operator &
6. cmd /c - Using the old cmd shell
7. Start-Process (start/saps)
8. [Diagnostics.Process] Start()
9. WMI Win32_Process Create() Method
Further Reading

1. Direct - Using the environment path or local folder (dot sourcing)

Why: Easy to use but is limited and not as stable.

Details: If a cmd is used without the prefixed .\ it will only be run if its in the environment path and will not look to the current directory without it. Not advised for using in scripts unless its for a system tool. Accepts args as if it were at a cmd prompt.

Example:

#Runs a ping, no .\ need since its in the sys 32 folder which is part of the environment path.

ping 127.0.0.1

#A test app that is run from the local folder but must be prefixed with the .\ because the current folder is no in the environment path.

.\testapp.exe

2. Invoke-Expression (IEX)

Technet
Why: Easy to execute a string. This can be VERY dangerous if used with user input.

Details: Accepts a string to be executed as code.

Example:

#Runs Get-Process

$str = "get-process"

Invoke-Expression $str

3. Invoke-Command (ICM)

Technet
Why: Great for executing code on multiple machines over WSMAN.

Details: Uses WimRM to run commands on the local or remote systems. It is not async and will run in the order provided to -computername. The results are returned in the order in which finishes first. If -AsJob is used, the job object is returned, otherwise it returns the results of script/code.

Example:

#runs ping on multiple machines

$scriptblock = {ping server3}

Invoke-Command -scriptblock $scriptblock -computername "server1","server2"

4. Invoke-Item (II)

Technet
Why: Forces the default action to be run on the item.

Details: Good when trying to open a file with an associated program. If for example you invoke-item with a PDF file, it will open it in whatever program is associated with PDF files. Can Also be used to open multiple files at once. Not good for executing a program.

Example:

#opens all PDFs in the current directory

Invoke-Item *.pdf

5. The Call Operator &

Technet
Why: Used to treat a string as a SINGLE command. Useful for dealing with spaces.

Details: Runs a command, script, or script block. The call operator, also known as the "invocation operator," lets you run commands that are stored in variables and represented by strings. Because the call operator does not parse the command, it cannot interpret command parameters

Example:

& 'C:\Program Files\Windows Media Player\wmplayer.exe' "c:\videos\my home video.avi" /fullscreen

6. cmd /c - Using the old cmd shell

Why: Bypasses PowerShell and runs the command from a cmd shell. Often times used with a DIR which runs faster in the cmd shell than in PowerShell.

Details: Opens a CMD prompt from within powershell and then executes the command and returns the text of that command. The /c tells CMD that it should terminate after the command has completed.

Example:

#runs DIR from a cmd shell, DIR in PowerShell is an alias to GCI. This will return the directory listing as a string but returns much faster than a GCI

cmd /c dir c:\windows

7. Start-Process (start/saps)

Technet
Why: Starts a process and returns the process object if -PassThru is provided. It also allows you to control the environment in which the process is started (user profile, output redirection etc). It also allows you to use the Verb (right click on a file, that list of actions) so that you can, for example, play a wav file.

Details: Executes a program returning the process object of the application. Allows you to control the action on a file (verb mentioned above) and control the environment in which the app is run. You also have the ability to wait on the process to end. You can also subscribe to the processes Exited event.

Example:

#starts a process, waits for it to finish and then checks the exit code.

$p = Start-Process ping -ArgumentList "invalidhost" -wait -NoNewWindow -PassThru

$p.HasExited

$p.ExitCode

8. [Diagnostics.Process] Start()

MSDN
Why: Allows a little more control. over the process object.
Details: There is a static Start method and a start method for the process object. No advantage that i know of to use this over Start-Process

Example:

#runs Notepad.exe using the Static Start method and opens a file test.txt

[Diagnostics.Process]::Start("notepad.exe","test.txt")

$ps = new-object System.Diagnostics.Process

$ps.StartInfo.Filename = "ipconfig.exe"

$ps.StartInfo.Arguments = " /all"

$ps.StartInfo.RedirectStandardOutput = $True

$ps.StartInfo.UseShellExecute = $ false

$ps.start()

$ps.WaitForExit()

[string] $Out = $ps.StandardOutput.ReadToEnd();

9. WMI Win32_Process Create() Method

MSDN
Why: The Create() method for the Win32_Process class can be run locally or remotely over RPC rather than WSMAN, to spawn a process and returns a System.Management.ManagementBaseObject#\__PARAMETERS object that lists the process id and return code of the process start up.

Details: This is a method in the Win32_Process class that allows creation of a process on a local or remote computer. There are multiple ways to use the Create() method. You can also provide Process Startup configuration data using the Win32_ProcessStartup class

Examples:

#Opens a notepad process using Invoke-WMIMethod

Invoke-WMIMethod -Class Win32_Process -Name Create -ArgumentList Notepad.exe

#Opens a batch file process on Remote Computer using Invoke-WMIMethod

Invoke-WMIMethod -Class Win32_Process -Name Create -Computername RemoteServer -ArgumentList "cmd /c C:\test.bat"

#Opens a notepad process using [wmiclass] accelerator

([wmiclass]"win32_Process").create('notepad.exe')

#Opens a notepad process with process startup configuration to hide the window using [wmiclass] accelerator

$startup=[wmiclass]"Win32_ProcessStartup"

$startup.Properties['ShowWindow'].value=$False

([wmiclass]"win32_Process").create('notepad.exe','C:\',$Startup)

#Opens a batch file process using [wmiclass] accelerator on remote system

([wmiclass]"\\remoteserver\root\cimv2:win32_Process").create('cmd /c C:\test.bat')