I bought a USB webcam recently and found a way to configure the device in the shell by using the v4l2-ctl command.
On my Ubuntu system I had to install the application first:
sudo apt install v4l-utils
The webcam is a video device so it's one of the devices listed in:
ls /dev/video*
To determine the right device you can show information about it with:
v4l2-ctl -d /dev/videoX --all
To show all controls with their supported values, defaults and current values use:
v4l2-ctl -d /dev/videoX -l
With -L instead of -l you get more information for menus. (Just give it a try.)
To set a certain control use:
v4l2-ctl -d /dev/videoX -c NAME_OF_CONTROL=VALUE
For example set brightness to 24:
v4l2-ctl -d /dev/video1 -c brightness=24