EDIT
EDIT [filename
[.extension
]
Invokes the system editor as specified by the value of the user variable _EDITOR. If the editor is invoked without a filename, the current contents of the buffer are passed to the editor and returned to the buffer when editing is complete.
The filename of a file to be opened by the editor. If filename does not exist, it will be created.
The extension portion of filename for those systems that support extensions.