man 5 shadow gives the following description of the third field in each line: The date of the last password change, expressed as the number of days since Jan 1, 1970. The value 0 has a ...
Here is a ruby script I wrote to change the timezone configuration on Ubuntu. I run it with jruby (a Ruby interpreter running in a JVM). require 'java' if ARGV.length == 0 puts "Usage: jruby ...