UnixTimeStamp 2.0 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free software for Mac OS X was originally designed by Akeb.ru. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The software lies within Productivity Tools, more precisely Timekeeping.
From the developer:
UnixTimeStamp is a time conversion tool for your Mac. The unix time stamp is a way to track time as a running total of seconds. This count starts at the Unix Epoch on January 1st, 1970 at UTC. Therefore, the unix time stamp is merely the number of seconds between a particular date and the Unix Epoch. It should also be pointed out that this point in time technically does not change no matter where you are located on the globe.
You may want to check out more software for Mac, such as Tea Timer, Missing Sync for Sony PSP or BigBen, which might be similar to UnixTimeStamp.