Identifying if a specific metadata type is used

[neebah]

Without searching for a specific tag is it possible to identify whether a tag of a specific group is present at all.  For example is it possible to identify if there is any XMP data or any IPTC data or any IFD1 data, etc present in a group of files?

[Phil Harvey]

This command will execute if there is any XMP in the file:

exiftool -if "$xmp:all" FILE

- Phil