With msiexec, what's the difference between these different ways to direct to the installer?

Question

I\'ve got a simple problem. I\'ve only found two ways that will actually run my msi file, and neither of them will work.

Pay close attention to my usage of \'

Answer 1

Powershell treats everything between single quotes as a literal string. Your variables won't get expanded if you use single quotes. So you need to use double quotes if you want to use variable expansion.
The problem with your example with the double quotes is that powershell interprets all the characters until a whitespace as a single variable. And since "$Basics\Installer_.64 bit_.msi" is not the variable that you want, this doesn't work either. You can put your variable name between curly brackets ({}) to delimit it from the rest of the string. So an example that would work is this:

Start-Process msiexec.exe -Wait -ArgumentList "/i ${Basics}\Installer_.64 bit_.msi"

Another option would be to use the format string operator:

'/i {0}\Installer_.64 bit_.msi' -f $Basics

This operator gives you a lot more freedom and you can do some very advanced string formatting with it. Another added benefit is that this way you can use single quotes. This makes sure that no expansion will take place. For example, in case your msi files have dollar signs in the name, the first example will not work, since powershell will try to expand the variables.