UUENCODE(5) File Formats Manual UUENCODE(5)
uuencode - format of an encoded uuencode file
Files output by uuencode(1C) consist of a header line, followed by a
number of body lines, and a trailer line. Uudecode(1C) 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 6 characters
"begin ". The word begin is followed by a mode (in octal), and a
string which names the remote file. A space separates the three items
in the header line.
The body consists of a number of lines, each at most 62 characters long
(including the trailing newline). These consist of a character count,
followed by encoded characters, followed by a newline. The character
count is a single 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.
uuencode(1C), uudecode(1C), uusend(1C), uucp(1C), mail(1)
1 June 1980 UUENCODE(5)