Caution: This version of this document is no longer maintained. For the latest documentation, see


Encode a binary file or standard input into ASCII (POSIX)


uuencode [-m] [file] name

Runs on:



Use the MIME Base64 encoding; otherwise use the uuencode historical algorithm.
The file that you want to encode. If you don't specify a file, uuencode reads from standard input.
The name to embed in the encoded file for use by uudecode.


The uuencode utility encodes a binary file as ASCII (e.g. for mailing). The encoding takes 3 bytes (24 bits) from the input file and renders them as 4 bytes in the output file.

By default, uuencode writes the encoded file to standard output. If you don't specify an input file, uuencode reads from standard input (unlike uue).

To decode the file, use uudecode.

See also:

uud, uudecode, uue