Tag: parameters

Parameter Hunting: Part II

In my last post on the subject, I discussed the concept of using Process Explorer to discover switches you can use for unattended installs/uninstalls used in enterprise software deployment.

Like before, I have a pesky setup.exe package that wants to guide me through an installation GUI, and would not respond to the usual setup.exe /s /q etc. and so forth…

This particular installer was for a very obscure serial hub manufacturer so there was Googling my way out of this; instead I needed to figure out what was used to build the installer, then work backward from there.

Once against, I launched my trusty Process Explorer (as Administrator) and inspected the setup.exe’s process…to my delight, scrolling down the “Strings” tab I came across this:

Note the string, “This installation was built with Inno Setup.” With that in mind, I was able to look up the documentation associated with the package builder to discover the built-in parameters I needed for silent installation.

While this specific technique might not work for every situation, it never hurts to have another tool in your toolbox!

Parameter Hunting

Preface: Often in our line of work, the answer requires a little digging. The purpose of this post is to walk you through my thought process in an effort to illustrate how I go about linking disparate pieces of information together to arrive at a solution.

Last week, I was tasked with creating a script to silently uninstall an application across a managed environment with nearly 800 endpoints spanning multiple physical locations and at least 3 separate domains – that was the easy part.

The hard part was that this application was installed as .EXE file rather than an MSI package (i.e. I couldn’t just script out msiexec /x…). While it did have an uninstall.exe file, this called the GUI uninstaller, and I wasn’t about to have someone go through and click ‘next’ ‘next’ ‘next’ for each one!

Many .EXE’s have CLI parameters you can invoke, so I started with the usual suspects:

  • uninstall.exe /?
  • uninstall.exe –?
  • uninstall.exe /help
  • uninstall.exe -help
  • uninstall.exe –help

None of these worked (it wouldn’t be post-worthy if it was that easy)!

Next, I went looking for any documentation that was available for the application – I had:

  • Googled the manufacturer for any documentation/examples – nada
  • Read all of the .txt files in the installation folder – zilch
  • Reviewed the .ini and .config files for clues, saw something vaguely useful – a reference to “NSIS” – tabled it and kept looking

Finally, I decided to use SysInternals Process Explorer to inspect the application:

  1. Run the application you want to inspect
  2. Open Process Explorer (as administrator)
  3. Find the application on the list
  4. Right click on the application and select “Properties…”
  5. Under the “Image” tab, you will see a field for “Command line:”

The Command line will tell you what commands/switches it runs. In this case, the uninstall.exe was running with the switch, “_?=C:\Program Files\[Application Name]”.

I decided to Google the switch itself, which lead me to the Nullsoft Scriptable Install System documentation. I was able to work out that the application used NSIS to create the installer/uninstaller package, and through that, found some examples, one of which (/S) runs the installer/uninstaller silently!

This was exactly what I was looking for! All I had to do was append the command with “/S”, and sure enough, it removed the application without any prompts or launching the GUI!

It just goes to show that persistence pays off, and a little time and effort can save your organization/client hundreds of hours of manual work.