Inserting additional comma delimiters in a csv file, after and before certian fields.

Shell Programming and Scripting
1

Hello

I have a csv file which I need to insert addtional commas into. The csv is of the format

field1,field2,field3,field4,...etc...,field13,field14

I need to add extra commas in each record so that the final output looks like

field1,field2,field3,field4,...etc...,field13,,,,field14,,,,,,,,

So specifically 3 addtional fields before the last field and a further 8 after.

There are no headers or footers in this file.

Is there a way of using sed or cut inorder to do this?

K

2 
sed "s/,[a-zA-Z0-9]*$/,,,&,,,,,,,,/"