JPEGEXIFORIENT(1) User Commands JPEGEXIFORIENT(1)NAME
jpegexiforient - reads or writes the Exif Orientation Tag
SYNOPSIS
jpegexiforient [switches] jpegfile
DESCRIPTION
This is a utility program to get and set the Exif Orientation Tag. It can be used together with jpegtran in scripts for automatic orienta-
tion correction of digital camera pictures.
The Exif orientation value gives the orientation of the camera relative to the scene when the image was captured. The relation of the '0th
row' and '0th column' to visual position is shown as below.
Value | 0th Row | 0th Column
------+-------------+-----------
1 | top | left side
2 | top | right side
3 | bottom | right side
4 | bottom | left side
5 | left side | top
6 | right side | top
7 | right side | bottom
8 | left side | bottom
For convenience, here is what the letter F would look like if it were tagged correctly and displayed by a program that ignores the orienta-
tion tag:
1 2 3 4
888888 888888 88 88
88 88 88 88
8888 8888 8888 8888
88 88 88 88
88 88 888888 888888
5 6 7 8
8888888888 88 88 8888888888
88 88 88 88 88 88 88 88
88 8888888888 8888888888 88
jpegexiforient output the Exif Orientation Tag in a JPEG Exif file. With the options -1 .. -8, it can also be used to set the tag.
OPTIONS
--help display this help and exit
--version
output version information and exit
-n Do not output the trailing newline
-1 .. -8
Set orientation value 1 .. 8
AUTHOR
Guido Vollbeding <guido@jpegclub.org>
SEE ALSO jpegtran(1), exifautotran(1)jpegexiforient February 2005 JPEGEXIFORIENT(1)
Check Out this Related Man Page
EXIFCOM(1) General Commands Manual EXIFCOM(1)NAME
exifcom - display or set the UserComment tag contained in a JPEG Exif section
SYNOPSIS
exifcom [ -bfinv ] [ -w comment ] [ -s delim ] file ...
DESCRIPTION
When invoked without arguments, the exifcom utility displays the contents of the Exif UserComment tag contained in file to the standard
output. Otherwise, depending on the options specified, exifcom will blank the tag or set it to comment.
Some digital cameras include a standard UserComment tag in the Exif data added to the image files they produce. This comment tag is fixed-
length and supports multi-byte character sets (though exifcom does not). Note that not all cameras will include the tag.
The utility is conservative in its approach to writing the UserComment tag. It does not modify, extend, or otherwise adulterate an image's
Exif metadata structure. When writing the tag it merely changes pre-allocated bytes. Therefore, exifcom is at the mercy of the Exif data
creator for both the presence of the tag and its length. It cannot create a UserComment tag when the camera does not include one, nor can
it write a comment longer than the space pre-allocated by the camera. exifcom only displays and writes ASCII character set comments.
OPTIONS -b Blank the UserComment tag, overwriting both the character code and comment fields with NUL. The character code specifies how the
comment is represented; it is "undefined" when blank. This is the state to which many cameras initialize the tag. When used in
conjunction with the -w option, exifcom will blank the comment prior to setting it to comment.
-f Overwrite or blank existing or unsupported comments without prompting for confirmation.
-i Write a prompt to standard error before overwriting or blanking an existing or unsupported comment. If the response from the stan-
dard input begins with 'y' or 'Y', the comment is overwritten. This option is default behavior.
-n Do not overwrite or blank existing or unsupported comments and do not prompt for confirmation (i.e., automatically answer 'no' to a
confirmation prompt). This option takes precedence over both the -f and -i options.
-s Separate field name and value in the verbose and multiple file cases with the string delim. The default is ': '.
-v Be verbose when printing the contents of the UserComment tag. Besides the comment itself (if present and supported), exifcom will
display the maximum comment length supported, the character code of the comment, and the length of the comment.
-w Set UserComment to the ASCII string comment. If comment is longer than what the tag supports, it will be truncated to fit.
DIAGNOSTICS
The exifcom utility exits 0 on success. When displaying a comment from a single file, if the UserComment tag is missing, it exits 1; if
blank, it exits 2; if in an unsupported character code, it exits 3. Otherwise, it exits 1 if an error occurs.
SEE ALSO exiftags(1), exiftime(1)STANDARDS
The exifcom utility was developed using the January 2002 Exif standard, version 2.2 (http://tsc.jeita.or.jp/).
BUGS
If the tag doesn't exist or is too short, too bad.
AUTHOR
The exifcom utility and this man page were written by Eric M. Johnston <emj@postal.net>.
EXIFCOM(1)