wp option
Examples
# Get site URL.
$ wp option get siteurl
http://example.com
# Add option.
$ wp option add my_option foobar
Success: Added 'my_option' option.
# Update option.
$ wp option update my_option '{"foo": "bar"}' --format=json
Success: Updated 'my_option' option.
# Delete option.
$ wp option delete my_option
Success: Deleted 'my_option' option.