$ TZ=PST8 erl
Erlang (BEAM) emulator version 5.5.4 [source] [async-threads:0] [kernel-poll:false]

Eshell V5.5.4  (abort with ^G)
1> Now = calendar:local_time().
{{2007,5,15},{16,4,31}}
2> erlang:localtime_to_universaltime(Now, true).
{{1969,12,31},{23,59,59}}
3> erlang:localtime_to_universaltime(Now, false).
{{2007,5,16},{0,4,31}}
4> wtf!