how to create checksums while images are captured with gphoto2

Question

I want to create an MD5 hash for each shot captured with gphoto2.

I tried to run this command

sudo gphoto2 -capture-image-and-download -force-overwrite \
 -filename capture.jpg -I 10 && md5sum capture.jpg > md5.txt

but the checksum writes only when gphoto2 was stopped. I need to write it for each shot as it is captured?

Answer 1

gphoto2 versions newer than 2.3.0 have the option --hook-script FILENAME ; you could write a short script file, eg named hook.sh :

case $ACTION in download) md5sum "$ARGUMENT" >md5.txt
esac

(don't forget to make it executable) and then

sudo gphoto2 -capture-image-and-download -force-overwrite \
 -filename capture.jpg -I 10 --hook-script hook.sh