What timezone formats exists on UNIX systems? Can someone gather them in a short answer? How can I recognize them?
Time zone data in modern UNIX systems comes from the public-domain IANA Time Zone Database. This database is what provides the timezone names, and the complex and ever-changing rules for timezones themselves. Wikipedia has a good overview of the database and the various formats in which it can be found, and includes a list of timezones from that database.