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	1	\cfg{man-identity}{base64}{1}{2004-11-20}{Simon Tatham}{Simon Tatham}
	2
	3	\define{dash} \u2013{-}
	4
	5	\title Man page for \cw{base64}
	6
	7	\U NAME
	8
	9	\cw{base64} \dash stand-alone encoder and decoder for base64
	10
	11	\U SYNOPSIS
	12
	13	\c base64 [ -d ] [ filename ]
	14	\e bbbbbb bb iiiiiiii
	15	\c base64 -e [ -c width ] [ filename ]
	16	\e bbbbbb bb bb iiiii iiiiiiii
	17
	18	\U DESCRIPTION
	19
	20	\cw{base64} is a command-line utility for encoding and decoding the
	21	\q{base64} encoding.
	22
	23	This encoding, defined in
	24	\W{http://www.ietf.org/rfc/rfc2045.txt}{RFC 2045}, is primarily used
	25	to encode binary attachments in MIME e-mail, but is widely used in
	26	many other applications as well. For example, the \q{Content-MD5}
	27	mail header contains a small piece of base64; SSH private keys are
	28	generally stored as base64-encoded blobs; and so on.
	29
	30	Other utilities, such as \cw{munpack}, exist which will take an
	31	entire MIME-encoded message, identify the base64-encoded subparts,
	32	and decode them. However, these utilities will not help you if you
	33	need to inspect a Content-MD5 header or an SSH private key.
	34
	35	\cw{base64} is a very simple stand-alone encoder and decoder for the
	36	base64 format \e{alone}. It does not try to understand MIME headers
	37	or anything other than raw data.
	38
	39	\U OPTIONS
	40
	41	By default (if neither \cw{-d} or \cw{-e} is supplied), \cw{base64}
	42	operates in decode mode.
	43
	44	\dt \cw{-d}
	45
	46	\dd Places \cw{base64} into decode mode. In this mode, it will read
	47	from standard input or the supplied file name, ignore all characters
	48	that are not part of the base64 alphabet, decode the ones that are,
	49	and output the decoded data on standard output.
	50
	51	\dt \cw{-e}
	52
	53	\dd Places \cw{base64} into encode mode. In this mode, it will read
	54	binary data from standard input or the supplied file name, encode it
	55	as base64, and output the encoded data on standard output.
	56
	57	\dt \cw{-c} \e{width}
	58
	59	\dd If \cw{base64} is operating in encode mode, this controls the
	60	number of base64 characters output per line of the encoded file.
	61	Normally base64-reading applications do not care about this, so the
	62	default of 64 characters per line is perfectly adequate.
	63
	64	\lcont{
	65
	66	The special value 0 will prevent \cw{base64} from ever writing a
	67	line break in the middle of the data at all.
	68
	69	The base64 encoding converts between a group of three plaintext
	70	bytes and a group of four encoded bytes. \cw{base64} does not
	71	support breaking an encoded group across a line (although it can
	72	handle it as input if it receives it). Therefore, the \e{width}
	73	parameter passed to \cw{-c} must be a multiple of 4.
	74
	75	}
	76
	77	\U LICENCE
	78
	79	\cw{base64} is free software, distributed under the MIT licence.
	80	Type \cw{base64 --licence} to see the full licence text.
	81
	82	\versionid $Id$