BASE64(1)BASE64(1)NAMEbase64 - encode / decode binary file as RFC 1341 MIME base64SYNOPSISbase64 -d|-e [ -n ] [ -u ] [ infile [ outfile ] ]
DESCRIPTION
The MIME (Multipurpose Internet Mail Extensions) specification (RFC
1341 and successors) defines a mechanism for encoding arbitrary binary
information for transmission by electronic mail. Triplets of 8-bit
octets are encoded as groups of four characters, each representing 6
bits of the source 24 bits. Only characters present in all variants of
ASCII and EBCDIC are used, avoiding incompatibilities in other forms of
encoding such as uuencode/uudecode.
base64 is a command line utility which encodes and decodes files in
this format. It can be used within a pipeline as an encoding or decod‐
ing filter, and is most commonly used in this manner as part of an
automated mail processing system.
OPTIONS--copyright Print program copyright information.
-d, --decode
Decodes the input, previously created by base64, to recover
the original input file.
-e, --encode
Encodes the input into an output text file containing its
base64 encoding.
-n, --noerrcheck
Suppress error checking when decoding. By default, upon
encountering a non white space character which does not
belong to the base64 set, or discovering the input file is
incorrectly padded to a multiple of four characters, base64
issues an error message and terminates processing with exit
status 1. The -n option suppresses even this rudimentary
error checking; invalid characters are silently ignored and
the output truncated to the last three valid octets if the
input is incorrectly padded.
-u, --help Print how-to-call information.
--version Print program version information.
EXIT STATUSbase64 returns status 0 if processing was completed without errors, 1
if an I/O error occurred or errors were detected in decoding a file
which indicate it is incorrect or incomplete, and 2 if processing could
not be performed at all due, for example, to a nonexistent input file.
FILES
If no infile is specified or infile is a single ``-'', base64 reads
from standard input; if no outfile is given, or outfile is a single
``-'', output is sent to standard output. The input and output are
processed strictly serially; consequently base64 may be used in pipe‐
lines.
BUGS
Little or no error checking is done when decoding, other than validat‐
ing that the input consists of a multiple of four characters in the
encoding set. This is inherent in the design of base64, which assumes
transmission integrity is the responsibility of a higher-level proto‐
col.
Please report bugs and documentation errors to bugs@fourmilab.ch.
SEE ALSOuudecode(1), uuencode(1), RFC1341
AUTHOR
John Walker
http://www.fourmilab.ch/
This software is in the public domain. Permission to use, copy, mod‐
ify, and distribute this software and its documentation for any purpose
and without fee is hereby granted, without any conditions or restric‐
tions. This software is provided ``as is'' without express or implied
warranty.
This is version 1.4 of base64. The current version of this program may
be downloaded from http://www.fourmilab.ch/webtools/base64.
4th Berkeley Distribution 20 FEB 2001 BASE64(1)
