keepcols
Usage:
keepcols <colid-list>
Select the columns from the input table which will be
included in the output table.
The output table will include only those columns listed in
<colid-list>, in that order.
The same column may be listed more than once,
in which case it will appear in the output table more than once.
Syntax for the <colid-list> argument is described in Section 6.3.