install.packages('optparse')
?optparse

##</code><code>##

install.packages('getopt')
.
.
.
  if(require("getopt", quietly=TRUE)) {
    opt <- getopt(matrix(c('path', 'p', 1, "character"),
                         ncol=4, byrow=TRUE))
    if(!is.null(opt$path))
      path <- opt$path
  }