Validating tab delimited file

Hi,

I have to make a report that have to upload tab delimited file from presentation server and perform operation then.

Now, can anyone tell me:

1. how to validate if file is tab delimited at all or not?

2.how to check if file has correct data i.e. say in the incoming file there should be 18 column, all of them can be filled or not at a time. how to check if file has data for required column only?

Regards

Ajit C