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authorJörg Frings-Fürst <debian@jff-webhosting.net>2015-05-01 16:24:15 +0200
committerJörg Frings-Fürst <debian@jff-webhosting.net>2015-05-01 16:24:15 +0200
commita30ba67504ffd12c4db499adbb5ce47a7d1f6036 (patch)
tree9ae1a7e3849dda6bbb5c578232f6f2fa5b2e7e7e /jpeg/rdjpgcom.1
parent89e99e8a827859729729dfc92d74be4a8f96f1a4 (diff)
parent094535c010320967639e8e86f974d878e80baa72 (diff)
New release 1.7.0
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+.TH RDJPGCOM 1 "02 April 2009"
+.SH NAME
+rdjpgcom \- display text comments from a JPEG file
+.SH SYNOPSIS
+.B rdjpgcom
+[
+.B \-raw
+]
+[
+.B \-verbose
+]
+[
+.I filename
+]
+.LP
+.SH DESCRIPTION
+.LP
+.B 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.
+.PP
+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.
+.SH OPTIONS
+.TP
+.B \-raw
+Normally
+.B rdjpgcom
+escapes non-printable characters in comments, for security reasons.
+This option avoids that.
+.PP
+.B \-verbose
+Causes
+.B rdjpgcom
+to also display the JPEG image dimensions.
+.PP
+Switch names may be abbreviated, and are not case sensitive.
+.SH HINTS
+.B 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.
+.PP
+In
+.B \-verbose
+mode,
+.B rdjpgcom
+will also attempt to print the contents of any "APP12" markers as text.
+Some digital cameras produce APP12 markers containing useful textual
+information. If you like, you can modify the source code to print
+other APPn marker types as well.
+.SH SEE ALSO
+.BR cjpeg (1),
+.BR djpeg (1),
+.BR jpegtran (1),
+.BR wrjpgcom (1)
+.SH AUTHOR
+Independent JPEG Group