Shell command help

Dear R Community,

I am trying to run a command line in R that will open an external program, have it import a specific input file, run the program, then close the program. The command line that I got from the developer of the model to do this looks like what you see below:

c:\programx.exe -import 'inputx.inp' -run -quit

I have been trying to use shell() or shell.exec() to run this in R.  I can get R to open the program but I have not been able to do the rest of the steps.

I have been able to open the model using :

shell('"C:\\programx.exe"')

or

shell.exec("C:\\programx.exe")

To do the rest I have been trying variations of the following:

shell('"C:\\programx.exe"' -import '"C:\\inputx.inp"' -run ?quit)

but I am not getting anywhere.

Can you provide any insight as to how to do the rest?

Thank you,

Galen