racket-command-line

#lang racket

(define fileName (make-parameter ""))
(define prefix (make-parameter ""))

(require racket/cmdline)
(define parser
  (command-line #:usage-help
                "input file name"
                "input prefix"
                #:once-each
                [("-f" "--fileName") inputFileName
                "fileName"
                (fileName inputFileName)]
                [("-p" "--prefix") inputPrefix
                "prefix"
                (prefix inputPrefix)]
                #:args () (void)
                )
  )

(displayln (fileName))
(displayln (prefix))