For example, if you want to enable or disable JetBackup 5, in the feature named default
To enable, run:
sed -i 's/jb5=0/jb5=1/' /var/cpanel/features/default
To disable, run:
sed -i 's/jb5=1/jb5=0/' /var/cpanel/features/default
If you want to enable for all feature sets, the target should be /var/cpanel/features/*