Convert unix text files to DOS text files (i.e., convert \n to \n\r)

[Dan Browning]

What utils are available (preferable ones that use STDIN, STDOUT, and
STDERR) to convert unix text files to DOS (win,etc.) text files and back?
Written in C, and can process gigabytes of small text files fast?

Dan Browning
Network Administrator
Cyclone Computer Systems