When using Setup.exe and you add arguments on the command line, you can access them through the CMDLINE system variable. You must remember that CMDLINE only stores user-defined command line switches. InstallShield command line switches are not copied to CMDLINE.

Now, in InstallScript MSI projects, you pass the command-line data to Setup.exe by using the /z switch as follows:

          setup.exe /z”arg1=value1 arg2=value2 arg3=value3″

Basic MSI projects are different. With those you pass public properties through Setup.exe to Msiexec.exe by using the /v command-line argument.