UUENCODE(5)                            File Formats Manual                            UUENCODE(5)



NAME
       uuencode - format of an encoded uuencode file

DESCRIPTION
       Files  output by uuencode(1) consist of a header line, followed by a number of body lines,
       and a trailer line.  The uudecode(1) command will ignore any lines preceding the header or
       following the trailer.  Lines preceding a header must not, of course, look like a header.

       The  header  line is distinguished by having the first 5 characters be begin followed by a
       space, or else a hyphen and either base64 or  encoded  or  both  (also  separated  with  a
       hyphen).   The  base64  option  says  the file has been encoded using base64.  The encoded
       option says the output file name has been base64 encoded.  It is never encoded with tradi‐
       tional uuencoding.  This is a GNU extension.  These are followed by a mode (in octal), and
       a string which names the remote file.  The mode is separated from the begin clause and the
       file name by a single space character.

   Traditional uuencoding
       The traditional uuencoded file body consists of a number of lines, each at most 62 charac‐
       ters long (including the trailing newline). These consist of  a  character  count  letter,
       followed  by the encoded characters, followed by a newline.  The character count is a sin‐
       gle printing character, and represents an integer, the number of bytes  the  rest  of  the
       line represents.  Such integers are always in the range from 0 to 63 and can be determined
       by subtracting the character space (octal 40) from the character.

       Groups of 3 bytes are stored in 4 characters, 6 bits per character.  All are offset  by  a
       space  to  make  the characters printing.  The last line may be shorter than the normal 45
       bytes.  If the size is not a multiple of 3, this fact can be determined by  the  value  of
       the  count on the last line.  Extra garbage will be included to make the character count a
       multiple of 4.  The body is terminated by a line with a count of zero.  This line consists
       of one ASCII space.

       The trailer line consists of end on a line by itself.

   base64 encoding
       base64  encoded  files follow the specified format for the body, but also include a begin-
       base64 header and a trailer line of four = characters.

EXAMPLES
            begin-base64-encoded 644 VE9ETw==
       This introduces a base64 encoded file named, TODO with  that  name  encoded  using  base64
       encoding.

            begin-encoded 644 5$]$3P``
       This  introduces an encoded file named, TODO with that name encoded using uuencoding.  The
       encoding is a lot less friendly.  Please prefer base64 encoding.

CONFORMING TO
       IEEE Std 1003.1, plus extensions

       The -encoded suffix to the begin header line is a GNU extension.  Recipients must have the
       GNU uudecode program to decode them.

SEE ALSO
       uuencode(1), uudecode(1), base64(1GNU)

HISTORY
       The uuencode file format appeared in BSD 4.0 .



                                                                                      UUENCODE(5)