#23456789_123456789_123456789_123456789_123456
perl -e'print map qw(G T A C)[rand(4)],1..pop' 1000

##</code><code>##

#23456789_123456789_123456789_123456789_12345
perl -e'print qw(G T A C)[rand(4)]for 1..pop' 1000

##</code><code>##

$c = (qw(A B C))[2];