The Execute Command routine stops program execution and directs
    the command language interpreter (CLI) to execute a command
    that you supply as the argument. If successful, LIB$DO_COMMAND
    does not return control to the calling program. Instead, LIB$DO_
    COMMAND begins execution of the specified command.

    If you want control to return to the caller, use LIB$SPAWN
    instead.

    Format

      LIB$DO_COMMAND  command-string