Library /sys$common/syshlp/lse$clihelp.hlb DEFINE, COMMAND, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 command-name
    Specifies the name to be defined as a command. A command name may
    contain up to 255 characters, but must begin with a letter, an
    underscore, or a dollar sign. After the first character, you may
    use any combination of alphanumeric characters, underscores, or
    dollar signs.

 value-string
    Specifies a quoted string containing an LSE command or the leading
    portion of an LSE command.