A         B        C       D
1.0E-1  2.0E-2  3.1E-3  3.0E-9
1.0E-1  2.0E-2  3.2E-3  3.0E-9
1.0E-1  2.0E-2  3.3E-3  3.0E-9
1.0E-1  2.0E-2  3.4E-3  1.0E-1
##</code><code>##

open (linedata, "/test.txt");
while  (<linedata>) {    
    ($A, $B, $C, $D) = split(/\t/, $_);
    print "$A, $B, $C, $D, \n"
    }
close (linedata);