What is Unix date format?

Unix time is a date-time format used to express the number of milliseconds that have elapsed since January 1, 1970 00:00:00 (UTC). Unix time does not handle the extra seconds that occur on the extra day of leap years.

How do I save a text file in Unix format?

To write your file in this way, while you have the file open, go to the Edit menu, select the “EOL Conversion” submenu, and from the options that come up select “UNIX/OSX Format”. The next time you save the file, its line endings will, all going well, be saved with UNIX-style line endings.