uuencode(5)
Name
uuencode − format of an encoded uuencode file
Description
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. Lines preceding a header must not, of course, look like a header.
The header line is distinguished by having the first six characters by the word “begin”, followed by a space. The next item on the line is 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 new line. These consist of a character count, followed by encoded characters, followed by a new line. 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 three bytes are stored in four characters, with six bits per character. All are offset by a space to make the characters print. The last line may be shorter than the normal 45 bytes. If the size is not a multiple of three, this fact can be determined by the value of the count on the last line. Extra dummy characters are included to make the character count a multiple of four. 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.