使用Linux shell命令从CSV文件中提取列

I need to "extract" certain columns from a CSV file. The list of columns to extract is long and their indices do not follow a regular pattern. So far I've come up with a regular expression for a comma-separated value but I find it frustrating that in the RHS side of sed's substitute command I cannot reference more than 9 saved strings. Any ideas around this?I need to "extract" certain columns from a CSV