By default, uuencode will encode using the traditional conversion. It is slower and less compact than base64. The encoded form of the file is expanded by 37% for UU encoding and by 35% for base64 encoding (3 bytes become 4 plus control information).
Since output file names may contain characters that are not handled well by various transmission modes, you may specify that the output-name be base64 encoded as well. (Traditional uuencoding of the file name is not supported.)
Please send bug reports to: bug-gnu-utils@gnu.org