Some time ago I built a little BASH library to wrap -stay_open and consecuting commands into a small library so that I can continue using exiftool in large scripts with many files in a simple but faster way.
I gave up. The speed was satisfying but there where some minor errors: I got wrong or repeated results. Probably this was because I overlooked the following sentence in the documentation which concerns my solution that uses files:
QuoteNote: When writing arguments to a disk file there is a delay of up to 0.01 seconds after writing -execute\n before exiftool starts processing the command. This delay may be avoided by sending a CONT signal to the exiftool process immediately after writing -execute\n.
How do I send this signal to the exiftool background process? I cannot find anything about this kind of signal.