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RDJPGCOM(1)		    General Commands Manual		   RDJPGCOM(1)

NAME
       rdjpgcom	- display text comments	from a JPEG file

SYNOPSIS
       rdjpgcom	[ -raw ] [ -verbose ] [	filename ]

DESCRIPTION
       rdjpgcom	 reads	the  named JPEG/JFIF file, or the standard input if no
       file is named, and prints any text comments found in the	 file  on  the
       standard	output.

       The  JPEG standard allows "comment" (COM) blocks	to occur within	a JPEG
       file.  Although the standard doesn't actually define  what  COM	blocks
       are for,	they are widely	used to	hold user-supplied text	strings.  This
       lets you	add annotations, titles, index terms, etc to your JPEG	files,
       and  later retrieve them	as text.  COM blocks do	not interfere with the
       image stored in the JPEG	file.  The maximum size	of a COM block is 64K,
       but you can have	as many	of them	as you like in one JPEG	file.

OPTIONS
       -raw   Normally	rdjpgcom escapes non-printable characters in comments,
	      for security reasons.  This option avoids	that.

       -verbose	Causes rdjpgcom	to also	display	the JPEG image dimensions.

       Switch names may	be abbreviated,	and are	not case sensitive.

HINTS
       rdjpgcom	does not depend	on the IJG JPEG	library.  Its source  code  is
       intended	 as  an	illustration of	the minimum amount of code required to
       parse a JPEG file header	correctly.

       In -verbose mode, rdjpgcom will also attempt to print the  contents  of
       any  "APP12" markers as text.  Some digital cameras produce APP12 mark-
       ers containing useful textual information.  If you like,	you can	modify
       the source code to print	other APPn marker types	as well.

SEE ALSO
       cjpeg(1), djpeg(1), jpegtran(1),	wrjpgcom(1)

AUTHOR
       Independent JPEG	Group

				 02 April 2009			   RDJPGCOM(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | HINTS | SEE ALSO | AUTHOR

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