To enable this, you need to create an empty file BOOT:quietcmd on your microSD to suppress sending 'OK' back to the user after every successful command received at the command line. Recommended for advanced users only.
In the console of JeVois inventor, you can type:
shell touch /boot/quietcmd
to achieve this. The JeVois command 'shell' sends everything that follows to a linux shell running on the camera. The linux command 'touch' updates the time stamp of a file, and creates an empty file if one did not already exist.
Note that the inventor requires OK to work. So, quit the inventor, unplug and re-plug JeVois, and you should be in quiet mode now. To delete the file, you will have to insert your microSD into a computer and delete the file from the BOOT partition.