youtube-dl --dateafter now-7days --playlist-end 10 --download-archive '/path/to/folder/downloaded.txt' -o '/path/to/folder/%(title)s.%(ext)s' -- 'https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw'

You can play around with the parameters to get the behavior you want (there are tons more than I don't use), I kept it pretty simple. In my case it checks the channel page for videos that are newer than 7 days (it runs daily but this gives me a buffer). If there are more than 10 videos newer than 7 days it only checks the first 10. It stores previously downloaded video information in downloaded.txt so it doesn't download duplicate videos, and outputs the video in the format videoName.ext.

Then throw that into a shell script along with any other channels you want and set up a cron job to run it as often as you'd like. You'll also probably want to put 'youtube-dl -U' into a cron job to keep it up to date, YouTube frequently changes things that breaks functionality of youtube-dl.