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 standard 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>.