The Free On-line Dictionary of Computing (30 December 2018):

EXEC 2

   1.  A scripting language produced by IBM in the
   late 1970s.

   Superseded by REXX.

   [SC24-5219, "Virtual Machine/System Product EXEC 2
   Reference"].

   [Successor to EXEC 1?  With or without a space?]

   2.  An archaic operating system from
   UNIVAC.  By about 1980 it had been replaced by EXEC 8.

   [Dates?  Did EXEC 3 to EXEC 7 exist?]

   (2000-08-06)