A parameter is an element of a command line, which determines how the command is carried out. External parameters follow a command on the command line before enter is pressed, or are passed to a command from a batfile or another program. Internal parameters are those contained within a batfile. Argument is another name for parameter. Switch refers to a specific non-variable parameter.
Replaceable parameters are a batfile's external parameters.
So far, we have worked with both simple and fixed batfiles, neither of which accepts parameters. Now we are going to work with batfiles which accept parameters entered at the prompt. DOS allows direct access to up to nine parameters entered on the command line after a batfile. There must be a space between the batfile name and the first parameter, and between each succeeding parameter. Whatever parameters a batfile uses are programed in by its creator.