This is the command exifcom that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
exifcom - display or set the UserComment tag contained in a JPEG Exif section
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.
-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
-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.
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.
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