How to get Command Line info for a process in PowerShell or C#

There is a permissions aspect to this too. The Powershell process needs to have permissions at least equivalent to the target process. So a regular Powershell session won't be able to get such information for a process running elevated (e.g. as Administrator). in this case, CommandLine (the response) will just be blank.

@CJBS To be precise you need admin privileges to be able to access that information about processes running in the context of another user. As a normal user it's only visible to you for processes running in your own context.

The value is still truncated to a certain length of characters. You can work around it by piping the result to "out-string -Width 2000" or something similar.

@mbrownnyc Using -Filter does the filtering on the remote host if your run Get-WmiObject against remote computers (using the -ComputerName parameter), reducing the amount of data that is transferred over the network (thus improving performance). Using Where-Object filters locally, after all WMI data was fetched from the remote host(s). It doesn't make a difference when running Get-WmiObject locally, though, like in this case. Also note that the syntax where property <op> value only works in PowerShell v3 or newer. Prior to that you must use where { $_.property <op> value }.

This didn't take much to figure out, but to save someone a few keystrokes, if you already have the process id (like from looking at CPU usage, etc) you can use "processid = 1234" - I use it for seeing which website is going rogue on our server (and there are 200 w3wp.exe processes)