BASE64(1)

NAME
base64 - encode / decode binary file as RFC 1341 MIME base64

SYNOPSIS
base64 -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 decoding 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 STATUS
base64 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 pipelines.

BUGS
Little or no error checking is done when decoding, other than validating 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 protocol.

Please report bugs and documentation errors to bugs@fourmilab.ch.

SEE ALSO
uudecode(1), uuencode(1), RFC1341

AUTHOR
    John Walker
    http://www.fourmilab.ch/

This software is in the public domain. Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, without any conditions or restrictions. 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.