Update the index just where it already has an entry matching . This removes as well as modifies index entries to match the working tree, but adds no new files.
If no <pathspec> is given when -u option is used, all tracked files in the entire working tree are updated (old versions of Git used to limit the update to the current directory and its subdirectories).__
$ git push -u origin HEAD
ssh: connect to host github.com port 22: Operation timed out
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.