Dateutils is a collection of tools for the quick manipulation of dates. The tool I use most frequently is
datediff. This program answers questions like: “How many days has it been since a date?” or “How many days are left in summer?”
$ datediff 2019-03-21 now 131 $ datediff now 2019-09-23 55
My second most frequently used program is
dateadd, which is used to add a duration to a date. It can answer questions like: “What will the date be in 3 weeks?”
$ dateadd now +3w 2019-08-20T02:02:23
The tools are much more powerful than these examples, but hardly a week goes by when I don’t use
dateadd for simple tasks like this.