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BASE64(1) General Commands Manual 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 decod- ing filter, and is most commonly used in this manner as part of an au- tomated 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 be- long 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 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 en- coding 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 ALSO uudecode(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)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | FILES | BUGS | SEE ALSO | AUTHOR
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