att.in

   1 v1      Version 1 AT&T UNIX
   2 v2      Version 2 AT&T UNIX
   3 v3      Version 3 AT&T UNIX
   4 v4      Version 4 AT&T UNIX
   5 v5      Version 5 AT&T UNIX
   6 v6      Version 6 AT&T UNIX
   7 v7      Version 7 AT&T UNIX
   8 32v     Version 32V AT&T UNIX
   9 V       AT&T System V UNIX
  10 V.1     AT&T System V.1 UNIX
  11 V.2     AT&T System V.2 UNIX
  12 V.3     AT&T System V.3 UNIX
  13 V.4     AT&T System V.4 UNIX