Uggggh. According to the POD from Date::Manip, PDT and PST are both valid values for TZ! Plus, there's no mention of 'PST8PDT', something I never would've guessed to try. :(

The following timezone names are currently understood (and can be used
in parsing dates).  These are zones defined in RFC 822.

  Universal:  GMT, UT
  US zones :  EST, EDT, CST, CDT, MST, MDT, PST, PDT
  Military :  A to Z (except J)
  Other    :  +HHMM or -HHMM
  ISO 8601 :  +HH:MM, +HH, -HH:MM, -HH
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How did you know that it needs to be PST8PDT for the Pacific time zone? Could you point me to some manpages, books, or hyperlinks?

The only box-specific timezone information I can find on my machine is ZONE="America/Los_Angeles" in /etc/sysconfig/clock, but I don't know if this is Redhat-specific. Could you point me to another file where the default timezone is garnered if TZ isn't set?

I did find a page which gives some specific examples on what to set TZ to. Anyone who finds more info, please share!

Update:
Found this mention of PST8PDT in the docs:

The timezone may be in the STD#DST format (in which case both abbreviations must be in the table above) or any of the formats described above.

However, this also implies that 'PDT' is a valid value for the TZ environment variable, but it doesn't seem to work correctly (see original question).

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