How to Set Date Time from Mac Command Line

By  on  

Working on a web extension that ships to an app store and isn't immediately modifiable, like a website, can be difficult. Since you cannot immediately deploy updates, you sometimes need to bake in hardcoded date-based logic. Testing future dates can be difficult if you don't know how to quickly change the date on your local machine.

To change the current date on your Mac, execute the following from command line:

# Date Format:  MMDDYYYY
sudo date -I 06142024

This command does not modify time, only the current date. Using the same command to reset to current date is easy as well!

Recent Features

  • By
    Being a Dev Dad

    I get asked loads of questions every day but I'm always surprised that they're rarely questions about code or even tech -- many of the questions I get are more about non-dev stuff like what my office is like, what software I use, and oftentimes...

  • By
    Welcome to My New Office

    My first professional web development was at a small print shop where I sat in a windowless cubical all day. I suffered that boxed in environment for almost five years before I was able to find a remote job where I worked from home. The first...

Incredible Demos

  • By
    Create a 3D Panorama Image with A-Frame

    In the five years I've been at Mozilla I've seen some awesome projects.  Some of them very popular, some of them very niche, but none of them has inspired me the way the MozVR team's work with WebVR and A-Frame project have. A-Frame is a community project...

  • By
    Fancy FAQs with jQuery Sliders

    Frequently asked questions can be super boring, right? They don't have to be! I've already shown you how to create fancy FAQs with MooTools -- here's how to create the same effect using jQuery. The HTML Simply a series of H3s and DIVs wrapper...

Discussion

  1. Richard

    I didn’t understand your exact use case, but a helpful way to do date-related testing without modifying your actual computer date/time, is to shim the system calls with library pre-loading. On a Mac, dyld can do this with DYLD_LIBRARY_PATH. On Linux, GNU ld can do it with LD_LIBRARY_PATH.

    This makes it easy to write tests for specific situations, such as monthly changeovers, leap-occurrences, timezones, etc.

    “libfaketime” is a handy library written for this, https://github.com/wolfcw/libfaketime. It’s even packaged in homebrew, just do brew install libfaketime. :)

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!