Library /sys$common/syshlp/dbg$help.hlb DEBUG, IF, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The IF command evaluates a Boolean expression. If the value is
    true (as defined in the current language), the command list in
    the THEN clause is executed. If the expression is false, the
    command list in the ELSE clause (if any) is executed.

    Related commands:

       EXITLOOP
       FOR
       REPEAT
       WHILE