I want to take a picture with the webcam every N time units and store it to /tmp/somefolder/ for further use with other tools and only keep the last M images. How to do this using webcam(UNIX COMMAND)? Any help appreciated.
Well ,why don't you try
fswebcam both are an excellent choices.
For using uvccapture, install using
sudo apt-get install uvccapture and to use
uvvcaputure -m -q100 -x640 -y480 -opic.jpg where pic.jpg is the filename.
Similarly install fswebcam and to use
webcam. Here you find more info regarding webcam https://help.ubuntu.com/community/Webcam