I am totally new to writing shell scripts.

What I want to do is that i want to do a conditional load of data from a flat file onto a table.

The data looks something like this

MBOC YR_1991 REGROLL BSPSIEB 1.000000 1.000000
ALLEP YR_1991 REGROLL COFYE 24.000000 24.000000
ALLEP YR_1991 REGROLL1 COLOP 48.000000 48.000000
ALLEP YR_1991 REGROLL2 COEPAM 8.000000 8.000000

It is in a fixed length format. I want to load only those records in which the 3rd field starting fom 21st column and ending at 30th is "REGROLL" or "REGROLL2" .

Please Help me out.