Tar archives can be transferred with remote copy commands rcp, ftp, kermit, and uucp. These utilities know how to deal with binary data. You will generally not use tar when mailing archived files, but you can first encode the files to make it work. The uuencode command turns the contents of files into printable characters using a fixed-width format that allows them to be mailed and subsequently decoded easily. The resultant file will be larger than the file before uuencoding; after all, uuencode must map a larger character set of printable and nonprintable characters to a smaller one of printable characters, so it uses extra bits to do this, and the file will be about a third larger than the original.