Here is a photo. This type of bug is eating all cabbages that I have planted some weeks ago. Apart from killing one by one, there is any solution? Probably they are living in the organic substrate.
Earwigs do most of their damage at night. What's at question is whether the soil you've used contained earwig eggs which have now hatched, since you didn't use sterilized potting medium, so you may find more arriving.
Earwigs eat mostly insects, though they do also like to nibble on flower petals quite frequently, and occasionally on plants, and I'm not seeing damage from earwigs on your seedlings, or any other damage actually, so I'm not sure why you think they are eating your seedlings.
If you have cabbages that have been outdoors for some months, I can't comment on what's damaged them because there are no images of the damage, and there are many insects which attack cabbages.
More extensive information on earwigs here http://entnemdept.ufl.edu/creatures/veg/european_earwig.htm, scroll down for its eating habits.
There aren't any insecticides that deal with earwigs, so the usual course of action is to use short, hollow canes laid in between plants, or flowerpots upside down on sticks filled with paper or straw - the earwigs will hide in those for shelter, so every morning, empty them out into a bucket of water and dispose of them.