Is covering the head a shar’i obligation?
Question

Could you give the scholars or mazhab names that their opinion stated that man also obligatory to cover their head.
Praise be to Allah.We do not know of anyone among the scholars who said that covering the head is obligatory for men, but a number of scholars have said that it is mustahabb, and they describe baring one’s head in front of people as being one of the things that undermine a man's status and character, especially if the man is elderly or is a scholar; if one of these people uncovers his head, that is worse than if anyone else does it. 
The correct view is that it is not one of the things that undermine a man's status and character in all eras and in all environments, rather the ruling on that varies according to people’s customs. 
Al-Shaatibi (may Allah have mercy on him) divided people’s customs into two categories: 
1 – Those concerning which there is shar’i evidence as to whether it is good or bad. In this case reference is to be made to sharee’ah, and what is customary among the people is of no importance. 
For example, uncovering the ‘awrah is reprehensible according to sharee’ah, even though many people are accustomed to doing that. 
Removing impurity is something that is good and is enjoined by sharee’ah, although many people do not pay attention to impurity on their clothes and do not protect themselves from that. 
2 – Things which are customary among people and there is no shar’i evidence to prohibit it or enjoin it. 
Such things are of two types: 
(a) Established customs that do not change, such as the desire for food and drink.
(b)Customs that change, such as whether an action is regarded as good or bad, which varies from one society to another.
Al-Shaatibi described this type by saying, “Such as uncovering the head, which varies from one place to another; in the lands of the east (i.e. Egypt and lands to the east) it is reprehensible for people of prominent status, and in the lands of the west (i.e., North Africa and Islamic Spain) it is not reprehensible. The shar’i ruling varies accordingly; for people in the east it is to be regarded as undermining a man’s status and character, whereas for the people in the west it is not. 
Al-Muwaaqifaat, 2/284 
The point is that covering the head for men is one of the issues concerning which reference should be made to what is customary among the people. A man should do what is customary in the society in which he lives, so long as that does not go against sharee’ah, and so that he will not stand out by being different from them in his clothing etc in the manner that is forbidden in sharee’ah. 
And Allah knows best.