def uid
      return nil unless user
      user.kind_of?(Integer) ? user : Etc.getpwnam(user.to_s).uid
    end
def uid
      return nil unless user
      user.kind_of?(Integer) ? user : Etc.getpwnam(user.to_s).uid
    end
The uid that the subprocess will switch to. If the user attribute was
 given as a username, it is converted to a uid by Etc.getpwnam
 TODO migrate to shellout/unix.rb