. file [ arg ... ]
       Read  commands  from  file  and execute them in the
       current shell environment.

       If file does not contain a slash, or  if  PATH DIRS
       is  set, the shell looks in the components of $path
       to find the directory containing  file.   Files  in
       the  current  directory  are  not  read  unless `.'
       appears  somewhere  in  $path.   If  a  file  named
       `file.zwc' is found, is newer than file, and is the
       compiled form (created with the  zcompile  builtin)
       of  file,  then  commands  are  read from that file
       instead of file.

       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.
