uuencode - format of an encoded uuencode file
Files output by uuencode consist of a header line followed by a number
of body lines, and a trailer line. The uudecode command ignores any
lines preceding the header or following the trailer (see uuencode(1)).
Lines preceding a header must not look like a header.
The header line consists of the word begin followed by a space, a mode
(in octal), another space, and a string which specifies the name of
the remote file.
The body consists of a number of lines, each containing 62 or fewer
characters (including trailing new-line). These lines consist of a
character count, followed by encoded characters, followed by a
The character count is a single printing character, which represents
an integer. This integer is the number of bytes in the rest of the
line, and always ranges from 0 to 63. The byte count can be
determined by subtracting the equivalent octal value of an ASCII space
character (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 printable. 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 meaningless data will be included, if
necessary, 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
The trailer line consists of the word end on a line by itself.
mail(1), uuencode(1), uucp(1).
Hewlett-Packard Company - 1 - HP-UX Release 11i: November 2000