在特定文件上使用R的内部tar函数

R has a handy cross platform tar() function that can tar and gzip files. It seems this function was designed to tar up entire directories. I was hoping to use this function to tar and compress a subset of a directory, or a single file. I can't seem to do this, however. I was expecting the following to tar up a single csv file in the current working directory:R has a handy cross platform tar() function tha