I am trying to make my setups scripts modular. I am calling setup exe\'s from within main setup script based to the requirements. I want to pass command line arguments to th
Try to get options from Command line by their name: http://nsis.sourceforge.net/Get_command_line_parameter_by_name
you can use GetOptions function (FileFunc.nsh must be included above). Following example shows p parameter reading; its value is saved into the variable. $CMDLINE is your command line (absolute or relative, as you called) containing also your parameters.
!include FileFunc.nsh
Var variable    
${GetOptions} $CMDLINE "/p" $variable