Thanks for the tutorial. Just a couple of small comments:
1) The –list option isn't doing what you think. ExifTool by default will list all tags. Adding –list tells it to list all tags except the tag named "list", which doesn't exist, so this option has no effect.
2) Tag names are not case sensitive, so "-comment" works just as well as "-Comment".
@XiphateXerenC: An even quicker way (sorry, ran out of room on the last comment), is to start typing a command and then hit TAB a few times. If the auto complete shows it, it's installed. If not, it's probable not installed.
@XiphateXerenC: I like "aptitude" as far as package managers are concerned. If you search for a package, their will be an "i" next to the package if it is installed.
sudo aptitude search exif
p exif – command-line utility to show EXIF information in JPEG files
The "p" at the beginning tells me it's not installed.
If it was installed, it would look like this (At lest for most things):
i exif – command-line utility to show EXIF information in JPEG files