exifcom - display or set the UserComment tag contained in a JPEG Exif
exifcom [ -bfinv ] [ -w comment ] [ -s
delim ] file ...
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.
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.
The exifcom utility was developed using the January 2002 Exif standard,
version 2.2 (http://tsc.jeita.or.jp/).
If the tag doesn't exist or is too short, too bad.
The exifcom utility and this man page were written by Eric M. Johnston
- 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.
- Overwrite or blank existing or unsupported comments without prompting for
- 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
- 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
- Separate field name and value in the verbose and multiple file cases with
the string delim. The default is ': '.
- 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.
- Set UserComment to the ASCII string comment. If comment is
longer than what the tag supports, it will be truncated to fit.