Hello, Please excuse the intrusion. I found this email address in some documents I downloaded from elsie.nci.nih.gov. I'm looking for some information or perhaps an online reference that can help me relate the output from the zdump utility to the changes for daylight savings for a particulat timezone. I've read the zic, zdump, ctime and localtime man pages. The zic manpage explains the format of the tz data files I found your name in. The output of zdump tells me when there is a change in the rules for a timezone but it doesn't seem to tell me what the rules are. In other words, given a particular zoneinfo file, how can I determine the zone and rules that were used to create it? My reason for asking is, how can I tell if the curent zoneinfo file is accurate given that governments can change the rules at any time. I've tried some experiments creating my own zoneinfo files then using zdump to display information about it but I see no way of determining the rules. Thanks for any help! John Reynolds john.reynolds@sciatl.com