Convert FASTA file RNA to DNA using sed on the linux command line

sed '/^[^>]/ y/uU/tT/' uracil.fasta > thymine.fasta 

Piece of cake.

lftp mirror: best way to download an entire directory from a FTP server

As much as I hate FTP, there situations where one must use it.  I finally have settled on the best way to get an entire directory, with recursive file retrieval:

lftp -e "mirror dir1/subdir2/subdir3" -u username,password ftphost.domain.com

Of course, FTP must die, but until then, I am glad there is lftp.