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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1 .TH RDJPGCOM 1 "13 September 2013"
2 .SH NAME
3 rdjpgcom \- display text comments from a JPEG file
4 .SH SYNOPSIS
5 .B rdjpgcom
6 [
7 .B \-raw
8 ]
9 [
10 .B \-verbose
11 ]
12 [
13 .I filename
14 ]
15 .LP
16 .SH DESCRIPTION
17 .LP
18 .B rdjpgcom
19 reads the named JPEG/JFIF file, or the standard input if no file is named,
20 and prints any text comments found in the file on the standard output.
21 .PP
22 The JPEG standard allows "comment" (COM) blocks to occur within a JPEG file.
23 Although the standard doesn't actually define what COM blocks are for, they
24 are widely used to hold user-supplied text strings. This lets you add
25 annotations, titles, index terms, etc to your JPEG files, and later retrieve
26 them as text. COM blocks do not interfere with the image stored in the JPEG
27 file. The maximum size of a COM block is 64K, but you can have as many of
28 them as you like in one JPEG file.
29 .SH OPTIONS
30 .TP
31 .B \-raw
32 Normally
33 .B rdjpgcom
34 escapes non-printable characters in comments, for security reasons.
35 This option avoids that.
36 .PP
37 .B \-verbose
38 Causes
39 .B rdjpgcom
40 to also display the JPEG image dimensions.
41 .PP
42 Switch names may be abbreviated, and are not case sensitive.
43 .SH HINTS
44 .B rdjpgcom
45 does not depend on the IJG JPEG library. Its source code is intended as an
46 illustration of the minimum amount of code required to parse a JPEG file
47 header correctly.
48 .PP
49 In
50 .B \-verbose
51 mode,
52 .B rdjpgcom
53 will also attempt to print the contents of any "APP12" markers as text.
54 Some digital cameras produce APP12 markers containing useful textual
55 information. If you like, you can modify the source code to print
56 other APPn marker types as well.
57 .SH SEE ALSO
58 .BR cjpeg (1),
59 .BR djpeg (1),
60 .BR jpegtran (1),
61 .BR wrjpgcom (1)
62 .SH AUTHOR
63 Independent JPEG Group