5.4.5 Example Row Filters

    [double && mag <= 5.0]        -  Extract all double stars brighter
                                     than  fifth magnitude 

    [#row >= 125 && #row <= 175]   - Extract row numbers 125 through 175

    [abs(sin(theta * #deg)) < 0.5] - Extract all rows having the
                                     absolute value of the sine of theta
                                     less  than a half where the angles
                                     are tabulated in degrees

    [@rowFilter.txt]               - Extract rows using the expression
                                     contained within the text file
                                     rowFilter.txt

    [gtifilter()]                  - Search the current file for a GTI
				     extension,  filter  the TIME
				     column in the current table, using
				     START/STOP times taken from
				     columns in the GTI  extension

    [regfilter("pow.reg")]         - Extract rows which have a coordinate
                                     (as given in the X and Y columns)
                                     within the spatial region specified
                                     in the pow.reg region file.