. file [ arg ... ]
       Read  commands  from  file  and execute them in the
       current shell environment.  If file does  not  con-
       tain  a  slash,  or  if PATH DIRS is set, the shell
       looks in the components of $path to find the direc-
       tory  containing file.  Files in the current direc-
       tory are not read unless `.' appears  somewhere  in
       $path.

       If  any  arguments  arg  are given, they become the
       positional parameters; the old  positional  parame-
       ters  are restored when the file is done executing.
       The exit status is the exit status of the last com-
       mand executed.

source file [ arg ... ]
       Same  as  .,  except  that the current directory is
       always  searched  and  is  always  searched  first,
       before directories in $path.
