/sys$common/syshlp/helplib.hlb EDIT, /TECO, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 file-name
    Specifies the file to be created or edited using the TECO editor.
    If the file does not exist, it is created by TECO, unless you
    specify the /NOCREATE qualifier. No wildcard characters are
    allowed in the file specification.

    If you specify the /MEMORY qualifier (default) without a file
    specification, TECO edits the file identified by the logical name
    TEC$MEMORY. If TEC$MEMORY has no equivalence string, or if the
    /NOMEMORY qualifier is specified, TECO starts in command mode and
    does not edit an existing file.

    If you specify the /MEMORY qualifier and a file specification, the
    file specification is equated to the logical name TEC$MEMORY.