What is the ruling on cutting some of a newborn's hair instead of shaving it on the seventh day of birth?

It is Sunnah (definition) to shave a boy's head on the seventh day of his birth and to give the weight of his hair in silver as charity, based on the Prophet's (peace and blessings be upon him) saying: "Every boy is mortgaged by his aqiqah (definition); it is slaughtered for him on his seventh day, he is named therein, and his head is shaved."

If shaving with a razor is difficult due to the unavailability of a skilled barber, there is no harm in omitting it and suffice with giving the estimated weight of his hair in silver as charity.