如何使用R将大型CSV数据文件分解为单个数据文件？

I have a CSV file the first row of which contains the variables names and the rest of the rows contains the data. What's a good way to break it up into files each containing just one variable in R? Is this solution going to be robust? E.g. what if the input file is 100G in size? I have a CSV file the first row of which contai