Uuencode

1 definition found

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  uuencode
       
          Unix program for encoding binary data as ASCII.  Uuencode was
          originally used with uucp to transfer binary files over serial
          lines which did not preserve the top bit of characters but is
          now used for sending binary files by e-mail and posting to


          {Usenet} newsgroups etc.  The program uudecode reverses the
          effect of uuencode, recreating the original binary file
          exactly.
       
          Uuencoded data starts with a line of the form
       
          	begin  
       
          where  is the files read/write/execute permissions as
          three {octal} digits and  is the name to be used when
          recreating the binary data.
       
          Uuencode repeatedly takes in a group of three bytes, adding
          trailing zeros if there are less than three bytes left.
          These 24 bits are split into four groups of six which are
          treated as numbers between 0 and 63.  Decimal 32 is added to
          each number and they are ouput as ASCII characters which will
          lie in the range 32 (space) to 32+63 = 95 (underscore).  Each
          group of sixty ouptut characters (corresponding to 45 input
          bytes) is output as a separate line preceded by an 'M' (ASCII
          code 77 = 32+45).  At the end of the input, if there are N
          output characters left after the last group of sixty and N>0
          then they will be preceded by the character whose code is
          32+N.  Finally, a line containing just a single space is
          output, followed by one containing just "end".
       
          Sometimes each data line has an extra dummy character added to
          avoid problems which mailers that strip trailing spaces.
          These characters are ignored by uudecode.
       
          Despite using this limited range of characters, there are
          still some problems encountered when uuencoded data passes
          through certain old computers.  The worst offenders are
          computers using non-ASCII character sets such as EBCDIC.