SSH and git public/private keys in Ubuntu

Today, git is used. Everything works normally on windows, but after installing git on Ubuntu, the following problems occur:

The sudo ssh-T git@github.com prompts permission denied (publickey ).Sudo git clone git@github.com: xiaomu/xmsc. Git prompt: Permission denied (publickey ).
Fatal: the remote end hung up unexpectedly but the ssh-T git@github.com is successfully executed while "Git clone git@github.com: xiaomu/xmsc. Git" not in ~ /Directory, The sudo write permission is required According to the analysis, the public and private keys generated by using the ssh-keygen command are stored in the current user ~ /. In the ssh/directory, but when using the sudo command, it is to go to/root /. SSH/to find the corresponding file, so the verification fails. Solution: 1) copy to the corresponding file; 2) use sudo ssh-keygen to generate;