Shell Programming and Scripting

I have a CSV file that is missing quotes around a column that contains text with commas. Example:

Code:

Column1, Column2, Column3, Column4, Column5, Column6
Data1, Data2, Data3, Data, 4, Data5, Data6
Data1, Data3, Data3, Data, text, 4, Data5, Data6

I think the easiest way for me to fix this is to replace the 3rd instance of a comma with a comma quote using the following sed command:

Code:

sed 's/,/,"/3' myfile.csv

The problem is that the 4th column has an unknown number of commas, so to provide the matching quote mark, I have to replace the 2nd to last instance of a comma with a quote comma. Unfortunately, I cannot figure out how to do this.

Suggestions?

Thanks.

Code:

sed 's/,/,"/3;s/\(,[^,]*,[^,]*\)$/"\1/' file

Thanks! That worked great! And I think I even understand how the pattern worked so I can reuse the search and replace if I get another CSV file with different columns from this transcription company that I need to fix up.