19 et al:

ensisun:~>uname -a
SunOS ensisun 5.10 Generic_118833-36 sun4u sparc SUNW,Sun-Fire-V890
ensisun:~>zdump
ensisun:~>zdump --help
zdump: option non admise -- help
zdump: [ --version ] [ -v ] [ -c [loyear,]hiyear ] zonename ...
ensisun:~>zdump --version
@(#)zdump.c     7.74
ensisun:~>zdump -v
ensisun:~>zdump -c
zdump: l'option c exige un argument
zdump: [ --version ] [ -v ] [ -c [loyear,]hiyear ] zonename ...
ensisun:~>zdump cet
cet  Tue Oct 16 20:04:57 2007 GMT
ensisun:~>zdump -v cet
cet  Tue Oct 16 20:05:00 2007 UTC = Tue Oct 16 20:05:00 2007 GMT isdst=0
cet  Fri Dec 13 20:45:52 1901 UTC = Fri Dec 13 20:45:52 1901 GMT isdst=0
cet  Sat Dec 14 20:45:52 1901 UTC = Sat Dec 14 20:45:52 1901 GMT isdst=0
cet  Tue Jan 19 03:14:07 2038 UTC = Tue Jan 19 03:14:07 2038 GMT isdst=0
cet  Mon Jan 18 03:14:07 2038 UTC = Mon Jan 18 03:14:07 2038 GMT isdst=0
ensisun:~>