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

 dcl-command
    Specifies the DCL command to be executed. If you do not specify
    a command, LSE prompts for one. Pressing CTRL/Z at the prompt
    cancels the operation.

    LSE splits the window to show the DCL buffer. You can edit the
    DCL buffer to move the output from the DCL command into another
    buffer. You can use the ONE WINDOW command to remove the DCL
    window.