This command executes the LAN-specific SDA extension image which is
    a collection of LAN-specific commands which mirror some of the display
    functions of SYS$SYSTEM:LANCP.EXE in SDA.

    By default this image is loaded from SYS$SHARE.  However, it can
    be redirected with the following logical:

 	$ define lan$sda [dir-spec]lan$sda.exe

    Format:

 	SDA> LAN command